ApplySet : `kubectl apply --prune` redesign and graduation strategy

[KnVerey]

Enhancement Description

• One-line enhancement description (can be used as a release note): This KEP proposes a safer and more performant implementation for kubectl apply's pruning feature, which enables cleanup of previously applied objects that have been removed from desired state provided to the current apply.
• Kubernetes Enhancement Proposal: https://github.com/kubernetes/enhancements/tree/master/keps/sig-cli/3659-kubectl-apply-prune
• Discussion Link: The SIG CLI maintainer track talk at Kubecon NA 2021 included a segment on the problem. Most recently, this was discussed in a Contributor Summit unconference session at Kubecon NA 2022 as well as async in this background doc, which was also raised in this SIG CLI meeting. In these recent conversations, there has been consensus that we need to finally do something to move this perma-alpha forward for 1.27; hence the creation of this KEP.
• Primary contact (assignee): @KnVerey
• Responsible SIGs: CLI
• Enhancement target (which target equals to which milestone):
  • Alpha release target (x.y): 1.27
  • Beta release target (x.y): TBD
  • Stable release target (x.y): TBD
• Alpha
  • KEP (k/enhancements) update PR(s):
    • KEP-3659: ApplySet: kubectl apply --prune redesign and graduation strategy #3661
  • Code (k/k) update PR(s):
    • Introduce CLI for ApplySet-based pruning kubernetes#115979
    • prunev2: Basic pruning logic kubernetes#116205
    • ApplySet: allow custom resources to be parent objects kubernetes#116353
    • Applyset dry run tests + ID value kubernetes#116265
    • Create and update the ApplySet parent object kubernetes#116243
    • kubectl diff: refactor tracker into a separate type kubernetes#116579
    • kubectl prunev2: simple e2e/integration test kubernetes#116599
    • kubectl prunev2: Refactor the applyset to be more reusable kubernetes#116580
    • kubectl prunev2: issue discovery requests in parallel kubernetes#116584
  • Docs (k/website) update PR(s):
    • Add docs for ApplySet-based pruning in kubectl apply website#39818

Please keep this description up to date. This will help the Enhancement Team to track the evolution of the enhancement efficiently.

/sig cli

[soltysh]

/assign @KnVerey
/stage alpha
/milestone v1.27
/label lead-opted-in

[marosset]

Hello @KnVerey 👋, Enhancements team here.

Just checking in as we approach enhancements freeze on 18:00 PDT Thursday 9th February 2023.

This enhancement is targeting for stage alpha for v1.27 (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: v1.27
• KEP readme has a updated detailed test plan section filled out
• KEP readme has up to date graduation criteria
• KEP has a production readiness review that has been completed and merged into k/enhancements.

For this enhancement, it looks like #3661 will address most of these requirements.
Please be sure to also:

• Update the status to implementable in the kep.yaml
• Record the PRR approval in a new file under https://github.com/kubernetes/enhancements/tree/master/keps/prod-readiness/sig-cli

The status of this enhancement is marked as at risk. Please keep the issue description up-to-date with appropriate stages as well.
Thank you!

[KnVerey]

@marosset I believe all of the requirements have been met with the merging of #3661 today!

[marosset]

This enhancement meets now meets all of the requirements to be tracked in v1.27.
Thanks!