support k8s.pod.hostname

[alburthoffman]

Component(s)

processor/k8sattributes

Is your feature request related to a problem? Please describe.

Spans from our client contain a host attribute, which is pod's hostname in the metadata.
And the bad news is pod's name is a little different from hostname.

Describe the solution you'd like

refer to this function: https://github.com/alburthoffman/opentelemetry-collector-contrib/blob/main/processor/k8sattributesprocessor/internal/kube/client.go#L288

We want to associate pod metadata based on the host attribute. But since k8s processor only support pod name, we could not do this.

Describe alternatives you've considered

had tried to constructs the pod name from the host attribute, but it requires using regex to extract substring.
And it also assumes that the name convention as well.

Overall it is not a good idea to do that by binding the name convention in our side.

Additional context

No response

[github-actions]

Pinging code owners:

• processor/k8sattributes: @dmitryax @rmfitzpatrick

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[dmitryax]

@alburthoffman how would you fetch the pod host name from k8s API?

[alburthoffman]

the hostname is a part of pod spec, which is described here: https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/#pod-s-hostname-and-subdomain-fields

[dmitryax]

I see. Ideally the hostname first should be added here https://github.com/open-telemetry/opentelemetry-specification/blob/main/semantic_conventions/resource/k8s.yaml#L48 ? Can you submit a PR for semantic conventions and the k8sattributes processor?

[alburthoffman]

sounds good. working on it. Thx

[codeboten]

Fixed by #18506