* The Kubelet now supports the `--require-kubeconfig` option which reads all client config from the provided `--kubeconfig` file and will cause the Kubelet to exit with error code 1 on error.  It also forces the Kubelet to use the server URL from the kubeconfig file rather than the  `--api-servers` flag.  Without this flag set, a failure to read the kubeconfig file would only result in a warning message. ([#30798](https://github.com/kubernetes/kubernetes/pull/30798), [@smarterclayton](https:...

- JWT authenticator config set via the --authentication-config flag is now dynamically reloaded as the file changes on disk. ([#123525](https://github.com/kubernetes/kubernetes/pull/123525), [@enj](https://github.com/enj)) [SIG API Machinery, Auth and Testing]

* Kubernetes server components using `kubeconfig` files no longer default to `http://localhost:8080`.  Administrators must specify a server value in their kubeconfig files. ([#30808](https://github.com/kubernetes/kubernetes/pull/30808), [@smarterclayton](https://github.com/smarterclayton))