[k8sprocessor] Watch pods in a set of namespaces

[gebn]

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

The processor is currently able to watch pods in a single namespace, on a single node, or across the entire cluster. In multi-tenant clusters, watching every pod is at best inefficient and worst forbidden, while looking at a single node is best-suited for DaemonSet deployments. This means the only option left is to have a processor or collector for each namespace of a multi-namespace application.

Describe the solution you'd like

It would be great if instead of a single namespace as is currently the case:

k8s_tagger:
  filter:
    namespace: foo

A list of namespaces could be passed:

k8s_tagger:
  filter:
    namespaces:
    - foo
    - bar
    - baz

Describe alternatives you've considered

• Run an OTel Collector deployment per namespace, either consolidated in a single namespace, or in the respective namespaces.
• Configure an instance of k8s_tagger for each namespace and list them in the pipeline, assuming the correct one will pick up a given pod and all others will ignore it.
• Configure a distinct pipeline for each namespace, each with a k8s_tagger instance filtering by that namespace. Each could use a receiver listening on a dedicated port.

Additional context

Prometheus's K8s service discovery is capable of watching multiple namespaces at once:

kubernetes_sd_configs:
- namespaces:
    names:
    - foo
    - bar
    - baz

[github-actions]

This issue has been inactive for 60 days. It will be closed in 60 days if there is no activity. To ping code owners by adding a component label, see Adding Labels via Comments, or if you are unsure of which component this issue relates to, please ping @open-telemetry/collector-contrib-triagers. If this issue is still relevant, please ping the code owners or leave a comment explaining why it is still relevant. Otherwise, please close it.

Pinging code owners:

• processor/k8sattributes: @owais @dmitryax

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[dmitryax]

This feature request makes sense but we don't have enough capacity to work on it at this point. Any help is appreciated. Should be implemented once we have e2e tests in place tho #15651

[github-actions]

This issue has been inactive for 60 days. It will be closed in 60 days if there is no activity. To ping code owners by adding a component label, see Adding Labels via Comments, or if you are unsure of which component this issue relates to, please ping @open-telemetry/collector-contrib-triagers. If this issue is still relevant, please ping the code owners or leave a comment explaining why it is still relevant. Otherwise, please close it.

Pinging code owners:

• processor/k8sattributes: @owais @dmitryax

See Adding Labels via Comments if you do not have permissions to add labels yourself.

[github-actions]

This issue has been closed as inactive because it has been stale for 120 days with no activity.