Diegolden

Topic 5: API Evolution And Versioning

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Topic 5: API Evolution And Versioning

Official baseline: (The Kubernetes Authors, 2026b, 2026a). My working version: Kubernetes APIs evolve. Good platform work knows which versions it depends on and when migrations are coming.

Mental Model

Kubernetes APIs evolve. Good platform work knows which versions it depends on and when migrations are coming.

Notes

  • API groups and versions are part of the contract.
  • Deprecated APIs are future work with a deadline.
  • CRD versioning needs the same respect as application APIs.

Homelab Angle

Run deprecation checks before upgrades. It is cheaper than discovering broken manifests during maintenance.

Verify It

  • Read the object status before changing the manifest.
  • Check events for the controller or node that is actually complaining.
  • Confirm the official source linked below still matches the cluster version you run.

Common Failure Modes

  • Treating the YAML object as the system, instead of one input to a reconciliation loop.
  • Debugging from outside the cluster when the failure only exists inside cluster networking or node state.
  • Forgetting that Kubernetes version, addon version, and runtime behavior are linked.

Sources

  • The Kubernetes API - source path: content/en/docs/concepts/overview/kubernetes-api.md, commit 8cc9e19b8eec8d5cf49eacd66f86a81648edb1a0.
  • Custom Resources - source path: content/en/docs/concepts/extend-kubernetes/api-extension/custom-resources.md, commit 8cc9e19b8eec8d5cf49eacd66f86a81648edb1a0.
  • Kubernetes documentation is licensed under CC BY 4.0; these notes are original commentary and link back to the official source.
The Kubernetes Authors. (2026a). Custom Resources. https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/custom-resources/
The Kubernetes Authors. (2026b). The Kubernetes API. https://kubernetes.io/docs/concepts/overview/kubernetes-api/

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