VPA updater: export admission controller status metric

[dippynark]

What type of PR is this?

/kind feature

What this PR does / why we need it:

If VPA updater is stuck taking action due to the admission controller status check, there is currently no way of detecting and alerting on this.

This PR fixes this by adding a corresponding metric so that we can alert on the following after 10 minutes:

increase(vpa_updater_admission_controller_status_invalid_total[5m]) > 0

Which issue(s) this PR fixes:

None

Special notes for your reviewer:

None

Does this PR introduce a user-facing change?

VPA updater metric added to expose admission controller status: vpa_updater_admission_controller_status_invalid_total

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

Summary by CodeRabbit

• Monitoring
  • Added Prometheus metrics for updater iterations skipped due to invalid Admission Controller status.
  • Metrics distinguish between status-check errors and invalid status results.

[kubernetes-prow]

This issue is currently awaiting triage.

If SIG Autoscaling contributors determines this is a relevant issue, they will accept it by applying the triage/accepted label and provide further guidance.

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between a1400fd and 6402840.

📒 Files selected for processing (2)

• vertical-pod-autoscaler/pkg/updater/logic/updater_test.go
• vertical-pod-autoscaler/pkg/utils/metrics/updater/updater_test.go

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📝 Walkthrough

Walkthrough

The updater now records invalid Admission Controller status events with separate reasons for validation errors and invalid status results. Tests cover metric recording and status-check error handling.

Changes

Admission Controller status metrics

Layer / File(s)	Summary
Record invalid Admission Controller status vertical-pod-autoscaler/pkg/utils/metrics/updater/updater.go, vertical-pod-autoscaler/pkg/updater/logic/updater.go, vertical-pod-autoscaler/pkg/utils/metrics/updater/updater_test.go, vertical-pod-autoscaler/pkg/updater/logic/updater_test.go	The updater registers a reason-labeled counter and records error or invalid when Admission Controller status checks fail. Tests cover both metric labels and status-check errors.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Merge Risk: ⚪ Minimal · up to 64028

This PR adds a localized metric for monitoring VPA updater admission-controller status; no actionable merge-blocking risk remains beyond normal checks and review.

Suggested reviewers: adrianmoisey, maxcao13, omerap12

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 7 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main change: exposing the VPA updater admission controller status metric.

• Fix all pre-merge checks with AI

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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[kubernetes-prow]

Hi @dippynark. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work.

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[kubernetes-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: dippynark
Once this PR has been reviewed and has the lgtm label, please assign adrianmoisey for approval. For more information see the Code Review Process.

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Details

Needs approval from an approver in each of these files:

• vertical-pod-autoscaler/OWNERS

Approvers can indicate their approval by writing /approve in a comment
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[adrianmoisey]

Is it possible to add a test for this?

[dippynark]

@adrianmoisey have added a couple covering the changed paths

[maxcao13]

/ok-to-test

[maxcao13]

Seems reasonable to me.

/lgtm

$ kubectl -n kube-system delete lease vpa-admission-controller
lease.coordination.k8s.io "vpa-admission-controller" deleted from kube-system namespace
$ kubectl -n kube-system port-forward deploy/vpa-updater 8943:8943

...
...
$ curl -s localhost:8943/metrics | grep admission_controller_status
# HELP vpa_updater_admission_controller_status_invalid_total Number of times Updater skipped its main loop because the Admission Controller status Lease was missing, stale or otherwise invalid.
# TYPE vpa_updater_admission_controller_status_invalid_total counter
vpa_updater_admission_controller_status_invalid_total{reason="error"} 1

[adrianmoisey]

/lgtm

Thanks!