[receiver/hostmetrics] Add process.start resource attribute

[andrzej-stencel]

Description:

This adds a resource attribute named process.start, in alignment with the Elastic Common Schema, to the metrics scraped by the process scraper of the hostmetrics receiver.

Link to tracking Issue:

• Enhance hostmetrics receiver process scraper to bring it closer to parity with telegraf procstat provided metrics #14084

Context:

Here's a discussion about the semantic convention for the attribute:

• Metrics Start-time resource semantic convention opentelemetry-specification#1273.

I'm not sure if changes to the semantic conventions are currently accepted, as described in these comments, but perhaps emitting an attribute that is already described by the Elastic Common Schema can be accepted?

[Aneurysm9]

I think this would be blocked as the project charter for the instrumentation stability project explicitly calls out the OTEP for including ECS support as blocked. I think this attribute in particular would also fall into the concern regarding adding high-cardinality attributes to metrics.

[andrzej-stencel]

I think this would be blocked as the project charter for the instrumentation stability project explicitly calls out the OTEP for including ECS support as blocked. I think this attribute in particular would also fall into the concern regarding adding high-cardinality attributes to metrics.

Thanks for the comment Anthony. Yeah, I recognize the attribute is a bit controversial both from the schema and cardinality perspective. There's a discussion on these topics in the specification repository too - both in the issue and in the pull request.

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[github-actions]

Closed as inactive. Feel free to reopen if this PR is still being worked on.