[DOC] Awareness Attribute Decommission

[imRishN]

What do you want to do?

• Request a change to existing documentation
• Add new documentation
• Report a technical problem with the documentation
• Other

Tell us about your request. Provide a summary of the request and all versions that are affected.
We have introduced a feature to decommission an awareness attribute from the cluster in the event of zonal failures. With decommissioning an awareness attribute, nodes having those attributes will be kicked out of the cluster and will stay out until the attribute is recommissioned back. Hence, these decommission/recommission APIs serves as an andon cord to cut-off inter-zone replication traffic.

We need to document a brief summary of the feature and all the new apis.
Details on api can be found in the opensearch-project/OpenSearch#3639.

Which versions are affected?
2.4.0

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.

1. High Level Proposal - Support for decommissioning and recommissioning a zone OpenSearch#3402
2. Design Proposal - [Design Proposal] Decommissioning and recommissioning a zone OpenSearch#3917
3. APIs RFC - [RFC] API for decommissioning/recommissioning zone and weighted zonal search request routing policy OpenSearch#3639
4. Meta Issues - [Meta] [Zone Decommission] Decommissioning and recommissioning a zone  OpenSearch#3957

Major PRs -

1. Add DecommissionService and helper to execute awareness attribute decommissioning OpenSearch#4084
2. Add APIs (GET/PUT) to decommission awareness attribute OpenSearch#4261
3. Controlling discovery for decommissioned nodes OpenSearch#4590
4. Add changes for graceful node decommission OpenSearch#4586
5. Service Layer changes for Recommission API OpenSearch#4320
6. Recommission api level support OpenSearch#4604

[imRishN]

@Naarcha-AWS any updates on this? Let me know if more details are required

[imRishN]

@Naarcha-AWS any updates?

[Naarcha-AWS]

I'll account for these as well with the 2.5 updates for #1811.