KEP-2053: Graduate DownwardAPIHugePages feature to stable

[saschagrunert]

• One-line PR description: We now graduate the DownwardAPIHugePages feature to stable.
• Issue link: Add downward API support for hugepages #2053
• Other comments: PTAL @kubernetes/sig-node-pr-reviews

[bart0sh]

/lgtm
/assign
/assign @derekwaynecarr

[bart0sh]

/assign @johnbelamaric

[saschagrunert]

@johnbelamaric are you fine with taking this for PRR?

[BenTheElder]

Hi @saschagrunert, PRR Shadows are going to do first pass reviews this cycle (recently announced here), I'll be shadowing this KEP and John will be following later with a follow-up review and PRR approval.

/assign

[BenTheElder]

Are we testing this? The test plan mentions skipping if the cluster doesn't support it, do we have a functioning test env?

Otherwise one nit about implementation history.

[saschagrunert]

Are we testing this? The test plan mentions skipping if the cluster doesn't support it, do we have a functioning test env?

Yes, we have a serial node e2e test suite covering it:
https://github.com/kubernetes/kubernetes/blob/f9a3fd2810ed4cba159b8d106ca7362c0b528c3a/test/e2e/common/node/downwardapi.go#L290-L388

[bart0sh]

/lgtm

[derekwaynecarr]

Just noting the test runs requesting 0 hugepages of the specified size and ensuring that is reflected in downward api. This ensures basic function works in environments where nodes advertise no huge pages.

see:
https://github.com/kubernetes/kubernetes/blob/f9a3fd2810ed4cba159b8d106ca7362c0b528c3a/test/e2e/common/node/downwardapi.go#L316

/approve
/lgtm

[saschagrunert]

@kubernetes/production-readiness PTAL again

[johnbelamaric]

We have one new PRR question this cycle, can you please add it and answer it? Otherwise LGTM. Thanks!

https://github.com/kubernetes/enhancements/tree/master/keps/NNNN-kep-template#can-enabling--using-this-feature-result-in-resource-exhaustion-of-some-node-resources-pids-sockets-inodes-etc

[saschagrunert]

We have one new PRR question this cycle, can you please add it and answer it? Otherwise LGTM. Thanks!

https://github.com/kubernetes/enhancements/tree/master/keps/NNNN-kep-template#can-enabling--using-this-feature-result-in-resource-exhaustion-of-some-node-resources-pids-sockets-inodes-etc

Yes, added the question and the corresponding answer.

[johnbelamaric]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: derekwaynecarr, johnbelamaric, mrunalp, saschagrunert

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Needs approval from an approver in each of these files:

• keps/prod-readiness/OWNERS [johnbelamaric]
• keps/sig-node/OWNERS [derekwaynecarr,johnbelamaric]

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[mrunalp]

/lgtm