- Kubeadm: during the validation of existing kubeconfig files on disk, handle cases where the "ca.crt" is a bundle and has intermediate certificates. Find a common trust anchor between the "ca.crt" bundle and the CA in the existing kubeconfig on disk instead of treating "ca.crt" as a file containing a single CA. ([#123102](https://github.com/kubernetes/kubernetes/pull/123102), [@astundzia](h...

- Kubeadm: warn but do not error out on missing "ca.key" files for root CA, front-proxy CA and etcd CA, during "kubeadm join --control-plane" if the user has provided all certificates, keys and kubeconfig files which require signing with the given CA keys. ([#94988](https://github.com/kubernetes/kubernetes/pull/94988), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

### Other (Cleanup or Flake)

### Other (Cleanup or Flake)

- `kubeadm alpha certs renew` and `kubeadm upgrade` now supports renewal of certificates embedded in KubeConfig files managed by kubeadm; this does not apply to certificates signed by external CAs.  ([#77180](https://github.com/kubernetes/kubernetes/pull/77180), [@fabriziopandini](https://github.com/fabriziopandini))

   ([#112907](https://github.com/kubernetes/kubernetes/pull/112907), [@logicalhan](https://github.com/logicalhan))

* The following deprecated flags were removed from `kubelet`:

  * `api-servers` - add apiserver addresses to the kubeconfig file instead.

  Don't use these flags. Using deprecated flags causes the kubelet to print a warning. Using a removed flag causes the kubelet to abort the startup.

- Fixed a bug that caused credentials in an exec plugin to override the static certificates set in a kubeconfig. ([#107410](https://github.com/kubernetes/kubernetes/pull/107410), [@margocrawf](https://github.com/margocrawf))

  much later). ([#122204](https://github.com/kubernetes/kubernetes/pull/122204), [@danwinship](https://github.com/danwinship))
- Fixed a regression in "kubeadm init" where a user-specified --kubeconfig file was being ignored. ([#122735](https://github.com/kubernetes/kubernetes/pull/122735), [@avorima](https://github.com/avorima))
- Fixed a regression in kubectl version `1.29.0` where the `--attach` flag was not honored.

- kubeadm: fix a potential panic if kubeadm discovers an invalid, existing kubeconfig file ([#79165](https://github.com/kubernetes/kubernetes/pull/79165), [@neolit123](https://github.com/neolit123))

- Kubeadm: Added support for additional authentication strategies in `kubeadm join` with discovery/kubeconfig file: client-go authentication plugins (`exec`), `tokenFile`, and `authProvider.` ([#110553](https://github.com/kubernetes/kubernetes/pull/110553), [@tallaxes](https://github.com/tallaxes))