- Kubeadm: allow RSA and ECDSA format keys in preflight check ([#112537](https://github.com/kubernetes/kubernetes/pull/112537), [@SataQiu](https://github.com/SataQiu)) [SIG Cluster Lifecycle]

## Dependencies

### Added
_Nothing has changed._

### Changed

- You can now use kubeadm's `InitConfiguration` and `JoinConfiguration` to define which preflight errors will be ignored. ([#75499](https://github.com/kubernetes/kubernetes/pull/75499), [@marccarre](https://github.com/marccarre))

- Kubeadm: do not use a DaemonSet for the pre-pull of control-plane images during "kubeadm upgrade apply". Individual node upgrades now pull the required images using a preflight check. The flag "--image-pull-timeout" for "kubeadm upgrade apply" is now deprecated and will be removed in a future release following a GA deprecation policy. ([#90788](https://github.com/kubernetes/kubernetes/pull/90788), [@xlgao-zju](https://...

- kubeadm no longer performs IPVS checks as part of its preflight checks ([#81791](https://github.com/kubernetes/kubernetes/pull/81791), [@yastij](https://github.com/yastij))

- Kubeadm: Add a preflight check that the control-plane node has at least 1700MB of RAM ([#93275](https://github.com/kubernetes/kubernetes/pull/93275), [@xlgao-zju](https://github.com/xlgao-zju)) [SIG Cluster Lifecycle]

### Other notable changes

* fix pdb validation bug on PodDisruptionBudgetSpec ([#48706](https://github.com/kubernetes/kubernetes/pull/48706), [@dixudx](https://github.com/dixudx))
* kubeadm: Fix join preflight check false negative ([#49825](https://github.com/kubernetes/kubernetes/pull/49825), [@erhudy](https://github.com/erhudy))

- Added support for RSA and ECDSA format keys in preflight check on `kubeadm`. ([#112508](https://github.com/kubernetes/kubernetes/pull/112508), [@SataQiu](https://github.com/SataQiu))

- Kubeadm: fixes a preflight check that can fail hostname construction in IPV6 setups ([#134589](https://github.com/kubernetes/kubernetes/pull/134589), [@liggitt](https://github.com/liggitt)) [SIG API Machinery, Auth, Cloud Provider, Cluster Lifecycle and Testing]

### Other notable changes

* Revert deprecation of vCenter port in vSphere Cloud Provider. ([#49689](https://github.com/kubernetes/kubernetes/pull/49689), [@divyenpatel](https://github.com/divyenpatel))
* kubeadm: Add preflight check for localhost resolution. ([#48875](https://github.com/kubernetes/kubernetes/pull/48875), [@craigtracey](https://github.com/craigtracey))

- Kubeadm: during "init" and "join" perform preflight validation on the host / node name and throw warnings if a name is not compliant ([#99194](https://github.com/kubernetes/kubernetes/pull/99194), [@pacoxu](https://github.com/pacoxu)) [SIG Cluster Lifecycle]