feat: promote StatefulSet metrics to STABLE and enhance docs #2783

yasicar · 2025-09-28T16:23:31Z

What this PR does / why we need it:

This PR promotes four StatefulSet metrics from EXPERIMENTAL to STABLE status and enhances StatefulSet monitoring documentation with practical examples.
Metrics Promoted to STABLE:
kube_statefulset_status_replicas_available
kube_statefulset_annotations
kube_statefulset_persistentvolumeclaim_retention_policy
kube_statefulset_deletion_timestamp

Why we need it:

Consistency with Kubernetes API Stability: All promoted metrics are based on stable Kubernetes v1 APIs:

Metrics Promoted to STABLE:

kube_statefulset_status_replicas_available
- K8s API Field: status.availableReplicas
- API Reference: StatefulSetStatus.availableReplicas
kube_statefulset_annotations
- K8s API Field: metadata.annotations
- API Reference: ObjectMeta.annotations
kube_statefulset_persistentvolumeclaim_retention_policy
- K8s API Field: spec.persistentVolumeClaimRetentionPolicy
- API Reference: StatefulSetSpec.persistentVolumeClaimRetentionPolicy
kube_statefulset_deletion_timestamp
- K8s API Field: metadata.deletionTimestamp
- API Reference: ObjectMeta.deletionTimestamp

, but the kube-state-metrics metric remained EXPERIMENTAL, This creates inconsistency where identical stable Kubernetes API fields have different stability levels across workload resources in kube-state-metrics.

Better monitoring: The documentation enhancements provide practical PromQL queries and alerting rules that address real-world StatefulSet monitoring needs, including detection of complete outages, rollout issues, and availability problems.
User experience: Removes confusion around metric stability and provides actionable examples for StatefulSet observability.

The promotion is justified because:

Same API field as STABLE metrics in Deployments (kube_deployment_status_replicas_available)
No changes to the metric since introduction in July 2021
Addresses actual monitoring gaps with practical alerting rules

How does this change affect the cardinality of KSM: (increases, decreases or does not change cardinality)

Which issue(s) this PR fixes:
Fixes #2794

- Updating kube_statefulset_status_replicas_available from ALPHA to STABLE - Add comprehensive PromQL examples and troubleshooting queries - Add major alerting rules for StatefulSet monitoring - Update tests to reflect STABLE status

linux-foundation-easycla · 2025-09-28T16:23:37Z

The committers listed above are authorized under a signed CLA.

✅ login: yasicar / name: yasicar (0db5451, 2b0139d, 61e72fb, 6e306c4, b42f1c0, b763076, bf43a47, d843208, deb8273, f37ce2a, fd61b08)

k8s-ci-robot · 2025-09-28T16:23:40Z

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- Fix malformed description column spacing in availableReplicas row - Align with consistent table formatting used by other metrics - Resolves markdownlint CI failure Signed-off-by: yasicar <[email protected]>

yasicar · 2025-09-30T03:25:31Z

@CatherineF-dev @mrueg Can you please help me with the review

nmn3m · 2025-10-03T16:22:02Z

docs/metrics/workload/statefulset-metrics.md

+## Common PromQL Queries
+
+### StatefulSet Health Monitoring
+


I noticed that you added some PromQL troubleshooting query examples under the metric definition. From my understanding, this file (docs/metrics/workload/statefulset-metrics.md) is meant to document the metrics themselves (type, labels, stability), not usage or example queries.

I think you should remove them.
Thanks.

Hi! Thank you for the feedback.
I added the PromQL examples because I noticed the Pod metrics documentation (docs/metrics/workload/pod-metrics.md) includes similar usage examples and queries, and the main README mentions welcoming "sample usages" contributions.
I was trying to follow that same pattern for consistency. Please add your thoughts.
I'm happy to adjust based on what works best for the project!

@yasicar, You are right, thanks for mentioning that.

@nmn3m Thanks
This is my first contribution to kube-state-metrics, and I'd really appreciate your help completing this review.

- Promote kube_statefulset_annotations to STABLE - Promote kube_statefulset_persistentvolumeclaim_retention_policy to STABLE - Promote kube_statefulset_deletion_timestamp to STABLE All metrics are based on stable Kubernetes v1 APIs: - metadata.annotations (v1 stable) - spec.persistentVolumeClaimRetentionPolicy (v1 stable) - metadata.deletionTimestamp (v1 stable) Addresses consistency gap between kube-state-metrics stability labels and underlying Kubernetes API stability."

nmn3m · 2025-10-05T11:39:45Z

internal/store/statefulset.go

 			"The number of available replicas per StatefulSet.",
 			metric.Gauge,
-			basemetrics.ALPHA,
+			basemetrics.STABLE,


This metric will need to be in BETA for a quite time then we can promote it to STABLE,
you can read this as I have the same situation before, #2749 (comment)

@nmn3m
Sure Thanks
I have addressed your comment and updated the entire PR to promote these metrics to BETA instead of STABLE.
d843208

Hi @nmn3m, any update on the review

Signed-off-by: yasicar <[email protected]>

…ps://github.com/yasicar/kube-state-metrics into promote-statefulset-available-replicas-and-docs

CatherineF-dev · 2025-10-08T17:56:57Z

internal/store/statefulset.go

 			"The number of available replicas per StatefulSet.",
 			metric.Gauge,
-			basemetrics.ALPHA,
+			basemetrics.BETA,


STABLE

We don't have BETA stage in KSM now.

KSM's STABLE is k8s's BETA, which means we can add labels.

Thanks @CatherineF-dev for reviewing
Got it, is it a recent change in KSM?

I have addressed your comments and reverted to STABLE b763076

k8s-ci-robot · 2025-10-10T16:07:54Z

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: nmn3m, yasicar
Once this PR has been reviewed and has the lgtm label, please assign catherinef-dev for approval. For more information see the Code Review Process.

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nmn3m · 2025-10-10T16:08:28Z

/ok-to-test

nmn3m · 2025-10-10T16:13:01Z

@yasicar, can you modify this part in PR body?, mention the issue that you are fixing,

Which issue(s) this PR fixes: (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged)
Fixes #

yasicar · 2025-10-10T16:23:57Z

@nmn3m There isn’t a tracked issue—this was self-identified—so I updated the PR body to note Fixes N/A (self-identified issue)

nmn3m · 2025-10-10T16:26:24Z

@yasicar, can you please create an issue?, describe what you are trying to do in that PR and attach that PR to it.

yasicar · 2025-10-10T16:37:54Z

@nmn3m Addressed your comments and created the issue

nmn3m · 2025-10-10T16:40:28Z

/triage accepted

yasicar added 2 commits September 28, 2025 21:50

promote-statefulset-available-replicas-and-docs

deb8273

- Updating kube_statefulset_status_replicas_available from ALPHA to STABLE - Add comprehensive PromQL examples and troubleshooting queries - Add major alerting rules for StatefulSet monitoring - Update tests to reflect STABLE status

Update statefulset-metrics.md

fd61b08

k8s-ci-robot requested review from CatherineF-dev and mrueg September 28, 2025 16:23

k8s-ci-robot added needs-triage Indicates an issue or PR lacks a `triage/foo` label and requires one. cncf-cla: no Indicates the PR's author has not signed the CNCF CLA. labels Sep 28, 2025

github-project-automation bot added this to SIG Instrumentation Sep 28, 2025

github-project-automation bot moved this to Needs Triage in SIG Instrumentation Sep 28, 2025

k8s-ci-robot added size/L Denotes a PR that changes 100-499 lines, ignoring generated files. cncf-cla: yes Indicates the PR's author has signed the CNCF CLA. and removed cncf-cla: no Indicates the PR's author has not signed the CNCF CLA. labels Sep 28, 2025

yasicar added 2 commits September 28, 2025 22:00

Update statefulset-metrics.md

b42f1c0

Update statefulset-metrics.md

f37ce2a

yasicar changed the title ~~Promote statefulset available replicas and docs~~ feat: promote StatefulSet availableReplicas to STABLE and enhance docs Sep 28, 2025

yasicar added 2 commits September 29, 2025 10:39

fix: correct markdown table formatting in statefulset metrics

2b0139d

- Fix malformed description column spacing in availableReplicas row - Align with consistent table formatting used by other metrics - Resolves markdownlint CI failure Signed-off-by: yasicar <[email protected]>

Update statefulset-metrics.md

bf43a47

k8s-ci-robot requested a review from dgrisonnet September 30, 2025 13:48

nmn3m reviewed Oct 3, 2025

View reviewed changes

yasicar changed the title ~~feat: promote StatefulSet availableReplicas to STABLE and enhance docs~~ feat: promote StatefulSet metrics to STABLE and enhance docs Oct 4, 2025

nmn3m reviewed Oct 5, 2025

View reviewed changes

yasicar added 3 commits October 5, 2025 19:31

feat: promote StatefulSet experimental metrics to BETA

d843208

feat: promote StatefulSet experimental metrics to BETA

61e72fb

Signed-off-by: yasicar <[email protected]>

Merge branch 'promote-statefulset-available-replicas-and-docs' of htt…

0db5451

…ps://github.com/yasicar/kube-state-metrics into promote-statefulset-available-replicas-and-docs

CatherineF-dev reviewed Oct 8, 2025

View reviewed changes

Promote StatefulSet metrics to stable

b763076

yasicar requested a review from CatherineF-dev October 10, 2025 14:03

yasicar requested a review from nmn3m October 10, 2025 14:03

nmn3m approved these changes Oct 10, 2025

View reviewed changes

k8s-ci-robot added the ok-to-test Indicates a non-member PR verified by an org member that is safe to test. label Oct 10, 2025

k8s-ci-robot added triage/accepted Indicates an issue or PR is ready to be actively worked on. and removed needs-triage Indicates an issue or PR lacks a `triage/foo` label and requires one. labels Oct 10, 2025

feat: promote StatefulSet metrics to STABLE and enhance docs #2783

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