kubeadm: make a control-plane's kubelet talk to the local API Server on kubeadm join.

[chrischdi]

Enhancement Description

• One-line enhancement description (can be used as a release note): Make the control-plane's kubelet talk to the local API Server on kubeadm join.

• Kubernetes Enhancement Proposal: https://github.com/kubernetes/enhancements/blob/master/keps/sig-cluster-lifecycle/kubeadm/4471-cp-join-kubelet-local-apiserver/README.md

• Discussion Link: make components on control-plane nodes point to the local API server endpoint kubeadm#2271

• Primary contact (assignee): @chrischdi

• Responsible SIGs: Cluster Lifecycle

• Enhancement target (which target equals to which milestone):

  • Alpha release target (x.y): 1.31
  • Beta release target (x.y): 1.33
  • Stable release target (x.y): TODO

• Alpha

  • KEP (k/enhancements) update PR(s):
    • KEP-4471: kubeadm: make a control-plane's kubelet talk to the local API Server on kubeadm join. #4496
    • KEP-4471: kubeadm: make a control-plane's kubelet talk to the local API Server on kubeadm join #4759
  • Code (k/k) update PR(s):
    • kubeadm: implement ControlPlaneKubeletLocalMode kubernetes#125582
    • kubeadm: consider feature gate ControlPlaneKubeletLocalMode on init and upgrade kubernetes#125780
  • Docs (k/website) update PR(s): kubeadm: add ControlPlaneKubeletLocalMode FG descriptions website#46945
  • kuebadm (k/kubeadm) and Test-infra (k/test-infra): update PR(s):
    • kinder: add test workflow for testing ControlPlaneKubeletLocalMode feature gate kubeadm#3080
    • kubeadm: add test workflow for testing ControlPlaneKubeletLocalMode feature gate test-infra#32858

• Beta

  • KEP (k/enhancements) update PR(s): KEP-4471: document graduation to beta #5138
  • Code (k/k) update PR(s):
    • kubeadm: Promote ControlPlaneKubeletLocalMode feature gate to beta kubernetes#129716
    • Revert "kubeadm: Promote ControlPlaneKubeletLocalMode feature gate to beta" kubernetes#129878
    • kubeadm: Promote ControlPlaneKubeletLocalMode feature gate to beta - second attempt kubernetes#129956
    • Unit and e2e test changes:
      • Update ControlPlaneKubeletLocalMode test for the feature gate being disabled kubeadm#3150
      • Revert "Update ControlPlaneKubeletLocalMode test for the feature gate being disabled" kubeadm#3156
      • Update ControlPlaneKubeletLocalMode test for the feature gate being disabled and fix setup-external-ca in kinder kubeadm#3157
  • Docs (k/website) update(s):
    • Update feature gate documentation kubeadm: Document ControlPlaneKubeletLocalMode promotion to beta website#49512

• Stable

  • KEP (k/enhancements) update PR(s):
    • sig-cl: promote 4471-cp-join-kubelet-local-apiserver to GA #5542
  • Code (k/k) update PR(s):
    • kubeadm: graduate ControlPlaneKubeletLocalMode to GA kubernetes#134106
  • e2e tests (k/kubeadm) PRs:
    • kinder: remove ControlPlaneKubeletLocalMode workflows after it goes GA kubeadm#3239
    • kubeadm: remove test job for ControlPlaneKubeletLocalMode test-infra#35540
  • Docs (k/website) update(s):
    • Fix pages to import the generated phases information which are not hidden anymore
      • ref docs only partially generated. for ga we should manually fix pages like kubernetes/website@main/content/en/docs/reference/setup-tools/kubeadm/kubeadm-init-phase.md and kubernetes/website@main/content/en/docs/reference/setup-tools/kubeadm/kubeadm-join-phase.md to import the generated files and update the phase order.
        kubernetes/website@main/content/en/docs/reference/setup-tools/kubeadm/generated
      • the generator is located here i think
        kubernetes-sigs/reference-docs@master/gen-compdocs/comps
      • it might work for you out of the box, but note it requires a k/k import from relative dir.
        kubernetes-sigs/reference-docs@master/gen-compdocs/go.mod#L215
      • kubeadm: update FGs and phases for 1.36 website#53644

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

• make components on control-plane nodes point to the local API server endpoint kubeadm#2271 (comment)
• Kubeadm office hours from 31st January 2024

cc @neolit123 : we discussed that this may not get tracked by enhancement tracking.

[neolit123]

we discussed that this may not get tracked by enhancement tracking.

yes, we are not going to opt-in for enhancement tracking for this feature.

[neolit123]

@chrischdi FYI, there is a PR that has been in review for a long time but it may merge in 1.30:
kubernetes/kubernetes#119598

we are thinking of adding a new dedicated join phase behind a feature gate, that waits for all k8s CP components (not etcd) to be ready.
basically ALA wait-control-plane for join.
note that it might conflict / mix things a little with this KEP.

[chrischdi]

@chrischdi FYI, there is a PR that has been in review for a long time but it may merge in 1.30: kubernetes/kubernetes#119598

we are thinking of adding a new dedicated join phase behind a feature gate, that waits for all k8s CP components (not etcd) to be ready. basically ALA wait-control-plane for join. note that it might conflict / mix things a little with this KEP.

Thanks for the heads up: it does not conflict with this proposal :-) it introduces stuff which happens after the parts this touches.

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[neolit123]

/remove-lifecycle stale

[k8s-triage-robot]

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

This bot triages un-triaged 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:

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

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

/lifecycle stale