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):
• 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):
  • Docs (k/website) update(s):

[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

[k8s-triage-robot]

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

This bot triages issues and PRs 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:

• Mark this issue or PR as fresh with /remove-lifecycle stale
• Mark this issue or PR as rotten with /lifecycle rotten
• Close this issue or PR with /close
• Offer to help out with Issue Triage

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

/lifecycle stale

[alculquicondor]

/remove-lifecycle stale

should be ready for GA in 1.24

[k8s-triage-robot]

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

This bot triages issues and PRs 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:

• Mark this issue or PR as fresh with /remove-lifecycle stale
• Mark this issue or PR as rotten with /lifecycle rotten
• Close this issue or PR with /close
• Offer to help out with Issue Triage

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

/lifecycle stale

[k8s-triage-robot]

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

This bot triages issues and PRs 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:

• Mark this issue or PR as fresh with /remove-lifecycle rotten
• Close this issue or PR with /close
• Offer to help out with Issue Triage

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

/lifecycle rotten

[k8s-triage-robot]

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

This bot triages issues and PRs 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 or PR with /reopen
• Mark this issue or PR as fresh with /remove-lifecycle rotten
• Offer to help out with Issue Triage

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

/close

[k8s-ci-robot]

@k8s-triage-robot: Closing this issue.

In response to this:

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

This bot triages issues and PRs 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 or PR with /reopen
• Mark this issue or PR as fresh with /remove-lifecycle rotten
• Offer to help out with Issue Triage

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

/close

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[damemi]

@alculquicondor did this ever move to GA?

[alculquicondor]

/reopen

No, still beta

[k8s-ci-robot]

@alculquicondor: Reopened this issue.

In response to this:

/reopen

No, still beta

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[janetkuo]

I removed 1.23 from Stable release target (x.y) in the issue description to avoid confusion.

[soltysh]

/milestone clear
since you can always check the latest-milestone in https://github.com/kubernetes/enhancements/blob/master/keps/sig-apps/2185-random-pod-select-on-replicaset-downscale/kep.yaml

[k8s-triage-robot]

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

This bot triages issues and PRs 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 or PR with /reopen
• Mark this issue or PR as fresh with /remove-lifecycle rotten
• Offer to help out with Issue Triage

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

/close

[k8s-ci-robot]

@k8s-triage-robot: Closing this issue.

In response to this:

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

This bot triages issues and PRs 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 or PR with /reopen
• Mark this issue or PR as fresh with /remove-lifecycle rotten
• Offer to help out with Issue Triage

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

/close

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[soltysh]

/reopen

[k8s-ci-robot]

@soltysh: Reopened this issue.

In response to this:

/reopen

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[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
• 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

[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

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.