KEP-4205: Graduate Expose PSI Metrics to GA by mariafromano-25 · Pull Request #5605 · kubernetes/enhancements

mariafromano-25 · 2025-10-02T22:01:56Z

One-line PR description:
This PR updates KEP-4205 to reflect the graduation of the "Expose PSI Metrics" feature to General Availability (GA), targeting the v1.35 release.
The KEP stage has been updated to stable and the latest-milestone is now v1.35.

Issue link: Support PSI based on cgroupv2 #4205

Other comments:
/kind documentation
/sig node
/assign @roycaihw

k8s-ci-robot · 2025-10-02T22:02:05Z

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k8s-ci-robot · 2025-10-02T22:02:07Z

Hi @mariafromano-25. Thanks for your PR.

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kannon92 · 2025-10-03T18:20:22Z

/ok-to-test

kannon92 · 2025-10-03T18:20:25Z

/ok-to-test

kannon92 · 2025-10-03T18:33:45Z

Two things:

Please add a prod-readiness file to request a PRR review for this KEP.
We normally avoid promoting features to GA if there are test failures

roycaihw · 2025-10-07T19:42:51Z

 NOTE: Also set `disable-supported` to `true` or `false` in `kep.yaml`.
 -->
-Yes
+Yes, but starting in v1.35 where this feature graduates to GA, the KubeletPSI feature gate will be locked to true and will no longer be disable-able.


s/1.35/1.36

roycaihw · 2025-10-07T19:47:26Z

 milestone:
  alpha: "v1.33"
  beta: "v1.34"
+  stable: "v1.36"


I wonder if we should leave the milestone unchanged. We can update it during the 1.36 cycle. When we update we should confirm that all GA criteria are met.

Either way we will need to update the latest-milestone: "v1.35" line when 1.36 comes.

updated to 1.36 for both!
for latest-milestone, the comment above mentioned that

# The most recent milestone for which work toward delivery of this KEP has been # done. This can be the current (upcoming) milestone, if it is being actively # worked on

and since Im actively working on it now, I updated it to 1.36

roycaihw · 2025-10-07T19:54:22Z

 #### GA
- Gather evidence of real world usage.
- No major issue reported.
+- Quantify the cAdvisor and kubelet-level overhead of PSI metric collection, especially where PSI is disabled at the kernel level.


Let's also ensure we cover stress testing scenario. We may need to expand on top of the previous performance benchmarking

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/lifecycle stale

mariafromano-25 · 2026-01-23T21:04:20Z

cc: @ndixita

ndixita · 2026-01-28T23:47:22Z

- No major issue reported.
+- Quantify the cAdvisor and kubelet-level overhead of PSI metric collection, especially where PSI is disabled at the kernel level.
+- Validate with SIG Node that collection overhead is acceptable for general use cases, or include opt-out knobs.
+- Exoanded stress testing with diverse environments and scenarios, while maintining acceptable minimal resource consumption like outlined in Beta perf testing.


Just checking if we have a list of different environments and scenarios that we plan to add tests for, we could document those as well.

ndixita · 2026-01-28T23:51:49Z

 NOTE: Also set `disable-supported` to `true` or `false` in `kep.yaml`.
 -->
-Yes
+Yes, but starting in v1.36 where this feature graduates to GA, the KubeletPSI feature gate will be locked to true and will no longer be disable-able.


nit: Yes, but starting in v1.36 where this feature graduates to GA, the KubeletPSI feature gate will be locked to true and can no longer be disabled.

kannon92 · 2026-01-31T01:17:17Z

#4205 (comment)

Should we investigate this before GA?

Co-authored-by: Dixita <[email protected]>

haircommander · 2026-02-09T20:04:52Z

#4205 (comment)

Should we investigate this before GA?

this was talked through on the bug and I believe not. This can be solved today with prometheus level metric filtering, and in the future CRI stats can choose with more granularity to expose these metrics on pod / infra container level or not. metrics are expensive, and that expense is generally considered worth it.

kannon92 · 2026-02-09T20:12:01Z

this was talked through on the bug and I believe not. This can be solved today with prometheus level metric filtering, and in the future CRI stats can choose with more granularity to expose these metrics on pod / infra container level or not. metrics are expensive, and that expense is generally considered worth it.

My main concern will be on regressions for those that don't implement this. Will we document or support a knob to filter out these pods? Or we just accept the performance hit and wait to solve it for a future KEP?

haircommander

on that line, I am feeling ready to approve this PR. I can imagine cases where a user would want to enable PSI but disable the metrics (because of the cost), but we don't currently allow users to disable any default container metrics in cadvisor. As we move to CRI stats, that opens the avenue for more granularity and ability to customize metrics exposed. Thus, the aforementioned cases can be handled by that, rather than introducing new kubelet config fields to do so. If customers want to enable PSI, they get these metrics. if they don't want the metrics, don't enable PSI. There's room to improve in the future.

I am curious if we feel we have enough real world data yet, but that will be teased out in the process of actually bumping to stable. let's make sure users are using it and are happy.

/approve

from SIG node side.

Thanks for the update @mariafromano-25 !

haircommander · 2026-02-09T20:12:06Z

+- Quantify the cAdvisor and kubelet-level overhead of PSI metric collection, especially where PSI is disabled at the kernel level.
+- Validate with SIG Node that collection overhead is acceptable for general use cases, or include opt-out knobs.
+- Expanded stress testing with diverse environments and scenarios, while maintining acceptable minimal resource consumption like outlined in Beta perf testing.
+- Gather evidence of real-world usage from beta users.


Do we have any data on this yet? Has Google enabled? Openshift allows customers to enable it but has not turned it on by default.

Google enables it by default, and there is no way for the user to turn it off at the moment.

Grepping for CONFIG_PSI in /boot/CONFIG-FILE CONFIG_PSI=y # CONFIG_PSI_DEFAULT_DISABLED is not set

The custom node system configurations documentation does not mention it either. But the beta performance test report indicated negligible overhead on both the node and kubelet level. I am working on more performance tests to also include the kernel.

johnbelamaric · 2026-02-09T21:28:23Z

/approve
/lgtm

k8s-ci-robot · 2026-02-09T21:28:33Z

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: haircommander, johnbelamaric, mariafromano-25

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k8s-ci-robot assigned roycaihw Oct 2, 2025

k8s-ci-robot added kind/documentation Categorizes issue or PR as related to documentation. sig/node Categorizes an issue or PR as relevant to SIG Node. cncf-cla: yes Indicates the PR's author has signed the CNCF CLA. labels Oct 2, 2025

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roycaihw reviewed Oct 7, 2025

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k8s-ci-robot added the lifecycle/stale Denotes an issue or PR has remained open with no activity and has become stale. label Jan 5, 2026

SergeyKanzhelev moved this to Triage in SIG Node 1.36 KEPs planning Jan 13, 2026

SergeyKanzhelev added this to SIG Node 1.36 KEPs planning Jan 13, 2026

SergeyKanzhelev removed this from SIG Node 1.36 KEPs planning Jan 13, 2026

mariafromano-25 added 2 commits January 23, 2026 20:31

updating doc to graduate psi metrics from beta to ga

154c1d4

updated GA requirements after oct 7 signode meeting

15dfa9e

mariafromano-25 force-pushed the update-kep-4205-to-ga branch from 243b641 to 15dfa9e Compare January 23, 2026 20:47

mariafromano-25 added 2 commits January 23, 2026 20:59

upating kep for 1.36 GA release

b7d1c14

addressing v comment

1d5b819

pacoxu mentioned this pull request Jan 27, 2026

Support PSI based on cgroupv2 #4205

Closed

34 tasks

ndixita reviewed Jan 28, 2026

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Comment thread keps/sig-node/4205-psi-metric/README.md Outdated

ndixita reviewed Jan 28, 2026

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mariafromano-25 and others added 2 commits February 6, 2026 15:55

Fix typo in KubeletPSI feature gate description

b5a141c

Update keps/sig-node/4205-psi-metric/README.md

5fd8b54

Co-authored-by: Dixita <[email protected]>

haircommander approved these changes Feb 9, 2026

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k8s-ci-robot assigned johnbelamaric Feb 9, 2026

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k8s-ci-robot added the approved Indicates a PR has been approved by an approver from all required OWNERS files. label Feb 9, 2026

k8s-ci-robot merged commit bf71aa0 into kubernetes:master Feb 9, 2026
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k8s-ci-robot added this to the v1.36 milestone Feb 9, 2026

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