Update PodMonitor for kube-proxy

[philipgough]

Description

The default PodMonitor that was shipped for kube-proxy was causing the target to never appear, and in SD, the target labels appeared as Dropped.

Because the PodMonitor has targetPort set, prometheus-operator is adding relabelling with action: keep which causes discovered targets to be kept, only if the regex matches a source label and since the DaemonSet for kube-proxy has no ports defined, we dont have __meta_kubernetes_pod_container_port_name label, and Prometheus doesn't have anything to match, so it discards the target.

/~https://github.com/prometheus-operator/prometheus-operator/blob/main/pkg/prometheus/promcfg.go#L745-L750

This is why the fix suggested in #1603 (comment) actually works.

Screenshot of targets up after this fix is applied:

Thanks @paulfantom for help investigating the solution.

Describe the big picture of your changes here to communicate to the maintainers why we should accept this pull request.
If it fixes a bug or resolves a feature request, be sure to link to that issue.

Fixes #1603

Type of change

What type of changes does your code introduce to the kube-prometheus? Put an x in the box that apply.

• CHANGE (fix or feature that would cause existing functionality to not work as expected)
• FEATURE (non-breaking change which adds functionality)
• BUGFIX (non-breaking change which fixes an issue)
• ENHANCEMENT (non-breaking change which improves existing functionality)
• NONE (if none of the other choices apply. Example, tooling, build system, CI, docs, etc.)

Changelog entry

Please put a one-line changelog entry below. Later this will be copied to the changelog file.

Add __address__ relabelling for kube-proxy PodMonitor to stop target being dropped

[ArthurSens]

Tested the setup on a local KinD cluster and confirmed it works as expected 👍

[yogeek]

Just had this issue with release-0.9 and finally found your fix : thank you ! But this was only merged into main...
Is it possible to backport this fix to 0.9 and 0.10 please ? (as this podmonitor has been added in 0.9 apparently)
@paulfantom

[paulfantom]

@yogeek yes, it is possible, are you willing to give it a try?

[yogeek]

@paulfantom thank your for your quick reply.
Yes I am going to try !

[yogeek]

@paulfantom here are the PRs :

• release-0.9 : Backport PodMonitor for kube-proxy to 0.9 release #1714
• release-0.10 : Backport PodMonitor for kube-proxy to 0.10 release #1715

Hope it is all right !