Support metadata resolution for multi-cloud envs

[movence]

Description of changes

Adds multi-cloud support for metric decoration and placeholder resolution. Azure (and future cloud providers)
use OTel's resourcedetectionprocessor for metadata, while EC2 continues using ec2tagger. Disk/volume tagging
is extracted into a standalone disktagger processor that supports both AWS and Azure.

Also include test fixes from #2010 and minor update to remove an unnecessary wrapper function (ref).

Cloud metadata (internal/cloudmetadata/)

• Cloud-agnostic Provider interface with AWS and Azure implementations
• Wraps re-exported metadataproviders from otel-contrib (no custom IMDS code)
• Singleton with auto-detection (AWS ? Azure), used by config-downloader and config-translator
• Replaces ec2util.GetEC2UtilSingleton() in all callers

Cloud provider enum (internal/cloudprovider/)

• Shared CloudProvider type (Unknown, AWS, Azure)

Re-export wrappers (otel-contrib)

• resourcedetectionprocessor/metadataproviders/{ec2,azure}/ exposes internal packages for external use

resourcedetection processor translator

• Added for non-EC2 pipelines (Azure, GCP)
• Reads append_dimensions and enables only requested attributes
• Supports OTel-style placeholders (${host.id}, ${azure.vm.size})

ec2tagger changes

• Removed all volume/disk tagging code (moved to disktagger)
• Supports OTel placeholders (${host.id}) alongside legacy (${aws:InstanceId})

disktagger processor (plugins/processors/disktagger/)

• Extracted from ec2tagger as standalone processor
• AWS: reuses existing volume package (DescribeVolumes + NVMe serial)
• Azure: IMDS storageProfile (OS + data disks) + /dev/disk/azure/ symlinks with sysfs SCSI fallback
• Prefix matching for partition names (e.g. sda1 matches sda)

Pipeline translator

• EC2 mode ? ec2tagger (unchanged)
• Non-EC2 ? resourcedetectionprocessor
• disktagger added when disk VolumeId/DiskId dimension is configured

Placeholder resolution

• Runtime placeholders (${aws:VolumeId}, ${disk.id}) stripped during translation
• cloudmetadata.GetProvider() replaces ec2util for metadata

Config examples

EC2 (backward compatible):

{"InstanceId": "${aws:InstanceId}", "VolumeId": "${aws:VolumeId}"}

EC2 (OTel style):

{"InstanceId": "${host.id}", "VolumeId": "${aws:VolumeId}"}

Azure:

{"InstanceId": "${host.id}", "Region": "${cloud.region}", "VolumeId": "${disk.id}"}

Known gap

Attribute renaming for non-EC2 clouds: resourcedetectionprocessor adds OTel semantic convention attributes (
e.g. host.id, cloud.region, azure.vm.size) to the Resource. These are not automatically renamed to CloudWatch
dimension names (e.g. InstanceId, Region, VMSize). The resource_to_telemetry_conversion setting copies them to metrics, but with OTel names for CW exporters.

License

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Tests

Tested on Ubuntu hosts in AWS and Azure by emitting CPU/MEM/DISK metrics

• AWS

• Azure

Requirements

Before commiting your code, please do the following steps.

1. Run make fmt and make fmt-sh
2. Run make lint

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Integration Tests

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