- kube-controller-manager currently needs a writable `--cert-dir` (default is `/var/run/kubernetes`) for generating self-signed certificates, when no `--tls-cert-file` or `--tls-private-key-file` are provided.

- kubeadm: Validate kubeconfig files in case of external CA mode. ([#70537](https://github.com/kubernetes/kubernetes/pull/70537), [@yagonobre](https://github.com/yagonobre))
- kubeadm: The writable config file option for extra volumes is renamed to readOnly with a reversed meaning. With readOnly defaulted to false (as in pod specs). ([#70495](https://github.com/kubernetes/kubernetes/pull/70495), [@rosti](https://github.com/rosti))

* Added the `writable` boolean option to kubeadm config. This option works on a per-volume basis for `ExtraVolumes` config keys. ([#60428](https://github.com/kubernetes/kubernetes/pull/60428), [@rosti](https://github.com/rosti))

All the features related to resource management (resource request/limit, quota, limitrange) are available for local ephemeral storage. This local ephemeral storage represents the storage for root file system, which will be consumed by containers' writable layer and logs. Some volumes such as emptyDir might also consume this storage. ([#60159](https://github.com/kubernetes/kubernetes/pull/60159), [@jingxu97](https://github.com/jingxu97))

* VolumeScheduling and LocalPersistentVolume features...

  volume with different fsgroups. When CSI migration is enabled for azurefile driver, such case is not supported.
  (there is a case we support where volume is mounted with 0777 and then it readable/writable by everyone) ([#96293](https://github.com/kubernetes/kubernetes/pull/96293), [@andyzhangx](https://github.com/andyzhangx))

- Added a alpha feature, behind the `RelaxedEnvironmentVariableValidation` feature gate.
  When that gate is enabled, Kubernetes allows almost all printable ASCII characters to be used in the names
  of environment variables for containers in Pods. ([#123385](https://github.com/kubernetes/kubernetes/pull/123385), [@HirazawaUi](https://github.com/HirazawaUi))

### Windows

- On Windows systems, `%USERPROFILE%` is now preferred over `%HOMEDRIVE%\%HOMEPATH%` as the home folder if `%HOMEDRIVE%\%HOMEPATH%` does not contain a `.kube\config` file, and `%USERPROFILE%` exists and is writable. ([#73923](https://github.com/kubernetes/kubernetes/pull/73923), [@liggitt](https://github.com/liggitt))

 - End-to-end testing has been migrated from Ginkgo v1 to v2.

- The metadata.clusterName field is deprecated. This field has always been unwritable and always blank, but its presence is confusing, so we will remove it next release. Out of an abundance of caution, this release we have merely changed the name in the go struct to ensure any accidental client uses are found before complete removal....