Pin serverless publish commit and add arch-specific image tags

[straistaru]

What does this PR do?

This PR does two things:

• Passes the commit info to the "Publish to serverless" pipeline.
• Tags internal internal release images per arch using a suffix (-amd64 or -arm64)

Why is it important?

The “Publish to serverless” pipeline currently builds off HEAD, which may differ from the commit for which it was triggered. Supplying the commit SHA ensures the promoted build matches what was verified.

Additionally, tagging images per architecture prevents a later single-arch rebuild of the same commit from temporarily overwriting the previously published multi-arch image. Without separate tags, users could pull an architecture that doesn’t match their host while the pipeline is still running.

Checklist

• I have read and understood the pull request guidelines of this project.
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in ./changelog/fragments using the changelog tool
• I have added an integration test or an E2E test

Disruptive User Impact

N/A

How to test this PR locally

Related issues

• Closes: https://github.com/elastic/ingest-dev/issues/6394

Questions to ask yourself

• How are we going to support this in production?
• How are we going to measure its adoption?
• How are we going to debug this?
• What are the metrics I should take care of?
• ...

[mergify]

This pull request does not have a backport label. Could you fix it @straistaru? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-./d./d is the label that automatically backports to the 8./d branch. /d is the digit
• backport-active-all is the label that automatically backports to all active branches.
• backport-active-8 is the label that automatically backports to all active minor branches for the 8 major.
• backport-active-9 is the label that automatically backports to all active minor branches for the 9 major.

[elasticmachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: 31e3601

Failed CI Steps

• arm:sudo: default
• x86_64:sudo: default - platform-ingest-elastic-agent-debian-11-1762801856

History

• 💔 Build #30696 failed 5f9278a

cc @straistaru

[michalpristas]

i think the change looks reasonable. manifest should contain updated sources

[straistaru]

Result of the test:

docker manifest inspect docker.elastic.co/observability-ci/ecp-elastic-agent-service:git-31e360145ec5
{
   "schemaVersion": 2,
   "mediaType": "application/vnd.docker.distribution.manifest.list.v2+json",
   "manifests": [
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 4924,
         "digest": "sha256:f5f8c8643c88088973bc5993ee54c258e942878ec417740d455f57b0e5b5dd90",
         "platform": {
            "architecture": "amd64",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 4924,
         "digest": "sha256:13e62b42c1b74d08528f19571babd345deb47dae8ee9b40014f021bd37afd399",
         "platform": {
            "architecture": "arm64",
            "os": "linux"
         }
      }
   ]
}