Random Pod selection on ReplicaSet downscaling

[alculquicondor]

Enhancement Description

• One-line enhancement description (can be used as a release note): When a ReplicaSet is downscaled, victim Pods are selected randomly
• Kubernetes Enhancement Proposal: https://git.k8s.io/enhancements/keps/sig-apps/2185-random-pod-select-on-replicaset-downscale
• Discussion Link: Pod Topology Spread constraints should be taken into account on scale down kubernetes#96748
• Primary contact (assignee): alculquicondor@, damemi@
• Responsible SIGs: sig-apps, sig-scheduling
• Enhancement target (which target equals to which milestone):
  • Alpha release target (x.y): 1.21
  • Beta release target (x.y): 1.22
  • Stable release target (x.y): 1.31
• Alpha
  • KEP (k/enhancements) update PR(s): Add KEP for random ReplicaSet downscale #2233
  • Code (k/k) update PR(s): Logarithmic timestamp comparison for downscaling kubernetes#99212
  • Docs (k/website) update PR(s): Add documentation for LogarithmicScaleDown featuregate website#27221
• Beta
  • KEP (k/enhancements) update PR(s): Update random pod scaledown KEP for beta #2691
  • Code (k/k) update PR(s): Promote LogarithmicScaleDown to Beta kubernetes#101767
  • Docs (k/website) update(s): Add documentation for LogarithmicScaleDown featuregate website#27221
• Stable
  • KEP (k/enhancements) update PR(s): Update random pod scaledown KEP for stable #4649
  • Code (k/k) update PR(s): Promote LogarithmicScaleDown to GA kubernetes#125459
  • Docs (k/website) update(s): Add documentation for LogarithmicScaleDown featuregate website#46865

[alculquicondor]

/sig apps
/sig scheduling

[alculquicondor]

cc @damemi

[damemi]

/assign

[damemi]

Haven't fogotten about this, just didn't get it in time for the new year... will open a PR soon based on @alculquicondor's draft

[damemi]

Filled out most of the sections and opened a KEP here: #2233

Looking for anything I missed or could improve on. Pretty straightforward mostly since it's not affecting a user-documented behavior

[jrsapi]

Greetings @damemi!
Since your Enhancement is scheduled to be in 1.21, please keep in mind the important upcoming dates:
• Tuesday, March 9th: Week 9 - Code Freeze
• Tuesday, March 16th: Week 10 - Docs Placeholder PR deadline
• If this enhancement requires new docs or modification to existing docs, please follow the steps in the Open a placeholder PR doc to open a PR against k/website repo.
As a reminder, please link all of your k/k PR(s) and k/website PR(s) to this issue so we can track them.
Thanks!

[damemi]

xref - wip PR kubernetes/kubernetes#96898

I'll be picking up this PR and working to get that merged for code freeze. Thanks for the update @jrsapi !

[damemi]

Opened new PR in kubernetes/kubernetes#99212

[jrsapi]

Greetings @damemi,

A friendly reminder that Code freeze is 5 days away, March 9th EOD PST
Any enhancements that are NOT code complete by the freeze will be removed from the milestone will require an exception to be added back.
Please also keep in mind that if this enhancement requires new docs or modification to existing docs, you'll need to follow the steps in the Open a placeholder PR doc to open a PR against k/website repo by March 16th EOD PST.
Thanks!

[alculquicondor]

Should we consider any updates to documentation for this? https://kubernetes.io/docs/concepts/workloads/controllers/replicaset/#scaling-a-replicaset

Current documentation doesn't give any details about internal selection, which might still be desired.

@janetkuo @soltysh

[janetkuo]

Yes, please update docs and the feature gate for this.

[PI-Victor]

Hello @damemi, 1.21 Docs shadow here.
Does this enhancement work planned for 1.21 require any new docs or modification to existing docs?
If so, please follows the steps here to open a PR against dev-1.21 branch in the k/website repo. This PR can be just a placeholder at this time and must be created by March 16 EOD PST
Also take a look at Documenting for a release to get yourself familiarize with the docs requirement for the release.
Thank you!

[damemi]

Yeah, I will open a PR to update the docs Aldo linked above

[damemi]

Docs PR opened at kubernetes/website#26993, which just copies the comments from code into the docs

[sreeram-venkitesh]

Hello @alculquicondor @MinpengJin @xuzhenglun 👋, v1.31 Enhancements team here.

Just checking in as we approach enhancements freeze on 02:00 UTC Friday 14th June 2024 / 19:00 PDT Thursday 13th June 2024.

This enhancement is targeting for stage stable for v1.31 (correct me, if otherwise)

Here's where this enhancement currently stands:

• KEP readme using the latest template has been merged into the k/enhancements repo.
• KEP status is marked as implementable for latest-milestone: v1.31. KEPs targeting stable will need to be marked as implemented after code PRs are merged and the feature gates are removed.
• KEP readme has up-to-date graduation criteria
• KEP has a production readiness review that has been completed and merged into k/enhancements. (For more information on the PRR process, check here).

For this KEP, everything is taken care of in #4649. Please make sure that it is merged in time before the enhancements freeze.

The status of this enhancement is marked as at risk for enhancement freeze. I can mark it as tracked as soon as the above PR is merged however! Please link the relevant PRs for beta in the issue description as well.

If you anticipate missing enhancements freeze, you can file an exception request in advance. Thank you!

[sreeram-venkitesh]

With #4649 merged, we can mark this KEP as tracked for enhancements freeze! 🎉

[a-mccarthy]

Hi @damemi @MinpengJin,

👋 from the v1.31 Communications Team! We'd love for you to opt in to write a feature blog about your enhancement!
Some reasons why you might want to write a blog for this feature include (but are not limited to) if this introduces breaking changes, is important to our users, or has been in progress for a long time and is graduating.

To opt in, let us know and open a Feature Blog placeholder PR against the website repository by 3rd July, 2024. For more information about writing a blog see the blog contribution guidelines.

Note: In your placeholder PR, use XX characters for the blog date in the front matter and file name. We will work with you on updating the PR with the publication date once we have a final number of feature blogs for this release.

[Princesso]

Hello @damemi , @MinpengJin 👋, 1.31 Docs Lead here.
Does this enhancement work planned for 1.31 require any new docs or modification to existing docs?
If so, please follow the steps here to open a PR against dev-1.31 branch in the k/website repo. This PR can be just a placeholder at this time and must be created before Thursday June 27, 2024 18:00 PDT.
Also, take a look at Documenting for a release to get yourself familiarised with the docs requirement for the release.
Thank you!

[a-mccarthy]

Hello @damemi, @MinpengJin, friendly reminder about the upcoming blog opt-in and placeholder deadline on July 3rd. Please open a blog placeholder PR if you are interested in contributing a blog.

[sreeram-venkitesh]

Hey again @alculquicondor @damemi @MinpengJin 👋 v1.31 Enhancements team here,

Just checking in as we approach code freeze at 02:00 UTC Wednesday 24th July 2024 / 19:00 PDT Tuesday 23rd July 2024 .

Here's where this enhancement currently stands:

• All PRs to the Kubernetes repo that are related to your enhancement are linked in the above issue description (for tracking purposes).
• All PR/s are ready to be merged (they have approved and lgtm labels applied) by the code freeze deadline. This includes tests.

List of associated PRs:

• Promote LogarithmicScaleDown to GA kubernetes#125459

If you anticipate missing code freeze, you can file an exception request in advance.

This KEP is marked as Tracked for code freeze. Thanks a lot for keeping the issue description up to date! Also, please let me know if there are other PRs in k/k we should be tracking for this KEP. As always, we are here to help if any questions come up. Thanks!

[alculquicondor]

I just added the documentation update PR that was missing in the description. With that, we are all set.

[k8s-triage-robot]

The Kubernetes project currently lacks enough active contributors to adequately respond to all issues and PRs.

This bot triages issues according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
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You can:

• Reopen this issue with /reopen
• Mark this issue as fresh with /remove-lifecycle rotten
• Offer to help out with Issue Triage

Please send feedback to sig-contributor-experience at kubernetes/community.

/close not-planned

[k8s-ci-robot]

@k8s-triage-robot: Closing this issue, marking it as "Not Planned".

In response to this:

The Kubernetes project currently lacks enough active contributors to adequately respond to all issues and PRs.

This bot triages issues according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 30d of inactivity since lifecycle/rotten was applied, the issue is closed

You can:

• Reopen this issue with /reopen
• Mark this issue as fresh with /remove-lifecycle rotten
• Offer to help out with Issue Triage

Please send feedback to sig-contributor-experience at kubernetes/community.

/close not-planned

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[soltysh]

/remove-lifecycle rotten