- Fixed node reporting...

 - Log messages in JSON format are written to stderr by default now (same as text format) instead of stdout. Users who expected JSON output on stdout must now capture stderr instead or in addition to stdout. ([#106146](https://github.com/kubernetes/kubernetes/pull/106146), [@pohly](https:...

- The `DeclarativeValidation` feature gate is enabled by default. When enabled, mismatches with existing hand written validation is reported via metrics.

- The PodDisruptionBudget API has been promoted to policy/v1 with no schema changes. The only functional change is that an empty selector (`{}`) written to a policy/v1 PodDisruptionBudget now selects all pods in the namespace. The behavior of the policy/v1beta1 API remains unchanged. The policy/v1beta1 PodDisruptionBudget API is deprecated and will no longer be served in 1.25+. ([#99290](https://...

	Read(p []byte) (n int, err error)
	Close() error
}

type Writer interface {
	Write(p []byte) (n int, err error)
	Close() error
}

// ReadWriter's methods are Read, Write, and Close.
type ReadWriter interface {
	Reader  // includes methods of Reader in ReadWriter's method set
	Writer  // includes methods of Writer in ReadWriter's method set
}
</pre>

<p>

* RBAC objects are now stored in etcd in v1 format. After completing an upgrade to 1.9, RBAC objects (Roles, RoleBindings, ClusterRoles, ClusterRoleBindings) should be migrated to ensure all persisted objects are written in `v1` format, prior to `v1alpha1` support being removed in a future release. ([#52950](https://github.com/kubernetes/kubernetes/pull/52950), [@liggitt](https://github.com/liggitt))

### Other notable changes

* **Multiple schedulers**
  * Modify your PodSpecs that currently use the `scheduler.alpha.kubernetes.io/name` annotation on Pod, to instead use the `schedulerName` field in the PodSpec.
  * Modify any custom scheduler(s) you have written so that they read the `schedulerName` field on Pod instead of the `scheduler.alpha.kubernetes.io/name` annotation.
  * Note that you can only start using the `schedulerName` field **after** you upgrade to 1.6; it is not recognized in 1.5.

- kubeadm: make sure the extra environment variables written to a kubeadm managed PodSpec are sorted alpha-numerically by the environment variable name. ([#126743](https://github.com/kubernetes/kubernetes/pull/126743), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

users must manually remove this flag from their `kubelet` configuration to prevent startup failures before upgrading `kubelet`. For `kubeadm` clusters, if users pass extra arguments to the `kubelet` like `--pod-infra-container-image`, it will be written to the `kubelet` env file during the `init` phase. `kubeadm` does not remove it during the `init` or `join` phase, so users must manually remove it from `extraArgs` in the `kubelet` configuration file. ([#133779](https://github.com/kubernetes/kub...

- Kubectl cluster-info dump changed to only display a message telling you the location where the output was written when the output is not standard output. ([#88765](https://github.com/kubernetes/kubernetes/pull/88765), [@brianpursley](https://github.com/brianpursley)) [SIG CLI]