Issues with Accessing Kubernetes API v3 after Upgrade – Cannot Fetch OpenAPI

General Discussions
1

Hi everyone,

After upgrading my Kubernetes cluster to version 1.32, I’m running into an issue where I’m unable to fetch the OpenAPI v3 schema. The view.kubernetes.io/docs/concepts/overview/kubernetes-api/ mentions that v3 is enabled by default, but when I try to access the endpoint /openapi/v3, I’m getting a 404 error. Here’s the command I’m running:

curl -X GET https://<cluster-url>/openapi/v3

The error response is:

{
  "message": "Not Found",
  "status": 404
}

I’ve double-checked the cluster settings, and the Kubernetes API server seems to be running fine. I also confirmed that API v2 is accessible at /openapi/v2.

Could this be an issue with the API server configuration or something related to API versioning? Any help in troubleshooting this would be appreciated!

Thanks!

2

In Kubernetes 1.32, the OpenAPI v3 endpoint may require explicit enabling. Try these steps:

  1. Check API Server Flags – Ensure the API server is started with --feature-gates=OpenAPIV3=true.
  2. Verify API Discovery – Run kubectl get --raw / to confirm /openapi/v3 is listed.
  3. Check RBAC Permissions – Ensure your user has get permissions on openapi. Test with:
    kubectl auth can-i get openapi --as=<your-user>
  4. Restart API Server – If the feature was enabled post-upgrade, a restart may be needed.

If the issue persists, check Kubernetes changelog and known issues for 1.32.