Dynamic Kubelet Configuration

[mtaufen]

Dynamic Kubelet Configuration

• One-line feature description (can be used as a release note):
  New Kubelet configurations can be rolled out in a live cluster
• Primary contact (assignee): @mtaufen
• Responsible SIGs: sig-node
• Design proposal (community repo)
• Documentation:
  • Low-level manual workflow
• Tests:
  • https://k8s-testgrid.appspot.com/sig-node-kubelet#kubelet-serial-gce-e2e&include-filter-by-regex=DynamicKubeletConfig
• Reviewer(s) - (for LGTM) recommend having 2+ reviewers (at least one from code-area OWNERS file) agreed to review. Reviewers from multiple companies preferred: @liggitt @thockin @dchen1107 @dashpole
• Approver (likely from SIG/area to which feature belongs): @dchen1107
• Feature targets (which target equals to which milestone):
  • Alpha release target (1.8):
    • Foundational primitives and Kubelet behavior implemented behind an Alpha feature gate
  • 1.9:
    • Incremental improvements working towards 1.10 goals
  • 1.10:
    • Improved testing, see Improve dynamic kubelet config testing kubernetes#50217
    • Kubelet configuration type reviewed and moved to beta
    • Kubelet loading configuration from a file moved to beta
  • Beta release target (1.11):
    • Node authorizer automatically allows access to the source specified by Node.Spec.ConfigSource node authorizer sets up access rules for dynamic config kubernetes#60100
    • Unpack remote configs to directories on the node: unpack dynamic kubelet config payloads to files kubernetes#59692
    • Make the Kubelet config key explicit:
      • PR: explicit kubelet config key in Node.Spec.ConfigSource.ConfigMap kubernetes#59847
    • Simplify skew scenarios/debugging by respecting ConfigMap mutations
      • Issue: Determine whether we should continue to require UID in node config source reference kubernetes#61643
      • PR: Kubelet responds to ConfigMap mutations for dynamic Kubelet config kubernetes#63221
    • Expose a structured status for dynamic config, rather than a node condition:
      • Issue: Consider a structured KubeletConfigOk field in Node.Status kubernetes#56896
      • PR: Move to a structured status for dynamic kubelet config kubernetes#63314
    • Expose metrics for Kubelet config:
      • PR: add dynamic config metrics kubernetes#57527
    • Kubelet config validation should respect target feature gate combination
      • Issue: Kubelet config: Validate new config against future feature gates kubernetes#63305
      • PR: Kubelet config: Validate new config against future feature gates kubernetes#63409
    • Improve test coverage of the file utils (pkg/kubelet/kubeletconfig/util/files/files.go):
      • PR: Improve test coverage of Kubelet file utils kubernetes#63496
    • Document the structure of the file tree under --dynamic-config-dir, other docs updates for 1.11
      • PR: update dynamic kubelet config docs for v1.11 website#8766
    • Document per-field advise for cluster administrators and k8s-as-a-service providers
      • PR: per-field dynamic config advice kubernetes#64354
    • Dynamic kubelet configuration moved to beta

[mtaufen]

Alpha PR: kubernetes/kubernetes#46254

[dchen1107]

Punt this to v1.8.

[luxas]

@mtaufen Any user/admin-facing docs ready for this feature?

[mtaufen]

No, I really need to write something to teach people how to play with the alpha. What's the preferred place for these docs again?

[luxas]

@mtaufen https://kubernetes.io/docs (https://github.com/kubernetes/kubernetes.github.io)
I'll definitely read what it came to look like finally