I have added “–runtime-config=rbac.authorization.k8s.io/v1alpha1” in “/etc/kubernetes/manifests/kube-apiserver.yaml” but still I do not see “rbac.authorization.k8s.io/v1alpha1” in “kubectl api-versions”? Why?
That’s an extremely old api version, which would explain that. The current version of that API is rbac.authorization.k8s.io/v1; the last lower level version of that API was rbac.authorization.k8s.io/v1beta1, which was pulled in v1.22. The v1alpha1 version of the API is so old that that K8s likely “knows” nothing about it. So you can ask for the version, but the system doesn’t know what to do with a version that old.