Add Host Metrics receiver to OTel mode

[andrzej-stencel]

What does this PR do?

This PR makes the Host Metrics receiver available to users running Elastic Agent in otel mode.

Why is it important?

This allows users to collect infrastructure metrics and is a prerequisite to support the infrastructure integration with OTel Collector.

Checklist

• 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

How to test this PR locally

1. Build the agent locally (see docs)
2. Unpack the .tar.gz archive in build/distributions
3. Run the built binary with `build/distributions/elastic-agent-*/elastic-agent otel --config internal/pkg/otel/testdata/all-components.yml

Related issues

• Closes Make hostmetricsreceiver available in otel mode #4724

[elasticmachine]

Pinging @elastic/elastic-agent-control-plane (Team:Elastic-Agent-Control-Plane)

[mergify]

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

• backport-v./d./d./d is the label to automatically backport to the 8./d branch. /d is the digit

NOTE: backport-skip has been added to this pull request.

[cmacknz]

The Windows startup errors are potentially due to significant delay added by the init() function in https://github.com/leoluk/perflib_exporter/blob/d0f3e166e8e144b7c5b02c55bbff65626c2077a3/perflib/perflib.go#L267.

Thanks to @leehinman for spotting this. I don't think there's anything you can do in Elastic Agent to get around this, this will have to be improved or removed upstream.

[andrzej-stencel]

The Windows startup errors are potentially due to significant delay added by the init() function in https://github.com/leoluk/perflib_exporter/blob/d0f3e166e8e144b7c5b02c55bbff65626c2077a3/perflib/perflib.go#L267.

Thanks to @leehinman for spotting this. I don't think there's anything you can do in Elastic Agent to get around this, this will have to be improved or removed upstream.

The https://github.com/leoluk/perflib_exporter repository is archived and recommends to use https://pkg.go.dev/github.com/prometheus-community/windows_exporter/pkg/perflib. This library apparently does not have the issue anymore. 🎉 prometheus-community/windows_exporter@11218a9#diff-a32807247e4aca11d44d5fefeab725bd8666039036720b9bd13ee154b19a896bL35

Let's add a replacement in go.mod and see if that helps. Simultaneously, I will push this fix in the upstream.

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube

[mergify]

This pull request is now in conflicts. Could you fix it? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b otel-add-host-metrics-receiver upstream/otel-add-host-metrics-receiver
git merge upstream/main
git push upstream otel-add-host-metrics-receiver

[andrzej-stencel]

Superseded by #4908