Tracking issue for In-place Updates implementation

[alexander-demicev]

This is a tracking issue for the implementation of in-place updates. At the moment, it only covers the work required for the initial phase of the project to reach the experimental (alpha) stage.

The design and approach are described in the in-place updates proposal.

• Initial refactorings / prereqs:

  • ✨ Ensure ExtensionConfig controller can be used outside of the core provider #12754
  • 🌱 Remove unused CleanUpManagedFieldsForSSAAdoption code #12788

• Add InPlaceUpdates feature gate: ✨Add inplace updates featuregate #12755

• Introduce Runtime Hook API changes, see examples section of the proposal for details.

  • Introduce CanUpdateMachine/CanUpdateMachineSet hooks and corresponding Request/Response types @alexander-demicev
  • Introduce UpdateMachine hook and corresponding Request/Response types @alexander-demicev
  • Define API contract for CanUpdateMachineRequest and CanUpdateMachineResponse
  • Define API contract for UpdateMachineRequest and UpdateMachineResponse

• Create reference external updater (CAPD Kubeadm Updater)

  • Set up the project structure
  • Implement handlers for both runtime endpoints
  • Implement container commands for upgrading Kubernetes components
  • Provide config samples for the updater

• Modify core controllers

  • KubeadmControlPlane controller updates
    • ✨ KCP: compare ClusterConfiguration via KubeadmConfig instead of annotation on Machine #12758
    • 🌱 Simplify cleanupConfigFields in KCP #12776
    • 🌱 Cleanup KCP code: variable/func renames, func order #12793
    • 🌱 Simplify KCP matchesKubeadmConfig #12813
    • [WIP] 🌱 KCP: Add current/desired objects to NotUpToDateResult #12817
    • See these parts of the proposal for details:
      • High-level flow
      • Deciding the update strategy
      • KCP updates
  • MachineDeployment controller updates
    • [Fabrizio] Add rollout planner part1: 🌱 Add rollout planner #12804
    • [Fabrizio] Fix issue in scale down old MS 🐛 Fix race conditions ScaleDownOldMS #12812
    • [Fabrizio] Add support for in-place in rollout planner part1: 🌱 Refactor MachineTemplateUpToDate #12811
    • Implement CanUpdateMachineSet
    • Change MS controller to handle move
    • See these parts of the proposal for details:
      • High-level flow
      • Deciding the update strategy
      • MachineDeployment updates
  • Machine controller modifications (@alexander-demicev)
    • See these parts of the proposal for details:
      • High-level flow
      • Deciding the update strategy
      • Machine updates
  • MHC: unhealthyMachineConditions (@furkatgofurov7): MHC should provide support for checking Machine conditions #5450

• Follow-ups

  • Consider if to improve the MS definition of Unhealthy when picking machines for deletion, see 🐛 Fix race conditions ScaleDownOldMS #12812 (comment)
  • Consider if to improve SSA helper to add items to the cache immediately after apply (currently they are added only after a no-op patch, so we are performing two apply for each change) (@lentzi90)

• Set up E2E testing

  • Implement E2E suite that uses the CAPD Kubeadm Updater

• Misc

  • Finalize all TODO(in-place)

• Create documentation

  • Feature flag configuration
  • New runtime hook and its API contracts
  • Updater structure and logic
  • Guide to implementing extensions
  • Explanation of the CAPD Kubeadm Updater
  • Tutorials for usage

Follow-up (after everything else is done, possibly in the next relase cyle)

• Improve ExtensionConfig pause behavior: updating the registry is also paused, warmup runnable ignores pause today

Docs

• Implementation design: https://docs.google.com/document/d/1MuhwSL-1ZMsiMoEHE9fVRha9Wkb5ORUFCLSMVNK_mTA/edit?tab=t.0

[k8s-ci-robot]

This issue is currently awaiting triage.

If CAPI contributors determine this is a relevant issue, they will accept it by applying the triage/accepted label and provide further guidance.

The triage/accepted label can be added by org members by writing /triage accepted in a comment.

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-sigs/prow repository.

[k8s-ci-robot]

@alexander-demicev: The label(s) /label kind/design cannot be applied. These labels are supported: api-review, tide/merge-method-merge, tide/merge-method-rebase, tide/merge-method-squash, team/katacoda, refactor, ci-short, ci-extended, ci-full. Is this label configured under labels -> additional_labels or labels -> restricted_labels in plugin.yaml?

In response to this:

/label kind/design

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-sigs/prow repository.

[alexander-demicev]

/kind design