* The dynamic Kubelet config feature will now update the config in the event of a ConfigMap mutation, which reduces the chance for silent config skew. Only name, namespace, and kubeletConfigKey may now be set in `Node.Spec.ConfigSource.ConfigMap`. The least disruptive pattern for config management is still to create a new ConfigMap and incrementally...

 in your manifest. An object with a spec.selector value that does not match the labels in
 its spec.template is invalid.

 - Selector mutation is disabled for all kinds in the
 app/v1beta2 group version, because the controllers in the workloads API do not handle
 selector mutation in
 a consistent way. This restriction may be lifted in the future, but
 it is likely that that selectors will remain immutable after the move to v1.

### **API Machinery**

#### **Admission Control**

*   Admission webhooks are now in beta, and include the following:
    *   Mutation support for admission webhooks. ([#54892](https://github.com/kubernetes/kubernetes/pull/54892),[ @caesarxuchao](https://github.com/caesarxuchao))

- Enabled a mechanism for concurrent log rotatation via `kubelet` using a configuration entity of `containerLogMaxWorkers` which controls the maximum number of concurrent rotation that can be performed and an interval configuration of `containerLogMonitorInterval` that can aid is configuring the monitoring duration to best suite your cluster's log generation standards. ([#114301](https://github.com/kubernetes/kubernetes/pull/114301), [@harshanarayana](https://github.com/harshanarayana)) [SIG...

#### TLS Bootstrapping
* [alpha] Rotation of the server TLS certificate on the kubelet. See [TLS bootstrapping - approval controller](https://kubernetes.io/docs/admin/kubelet-tls-bootstrapping/#approval-controller).

- Kubeadm: retry `kubeadm-config` ConfigMap creation or mutation if the apiserver is not responding. This will improve resiliency when joining new control plane nodes. ([#85763](https://github.com/kubernetes/kubernetes/pull/85763), [@ereslibre](https://github.com/ereslibre)) [SIG Cluster Lifecycle]

- Setting a mirror pod's phase to Succeeded or Failed can prevent the corresponding static pod from restarting due mutation of a Kubelet cache. ([#116482](https://github.com/kubernetes/kubernetes/pull/116482), [@smarterclayton](https://github.com/smarterclayton)) [SIG Node]

- Adds `\livez` for liveness health checking for kube-apiserver. Using the parameter `--maximum-startup-sequence-duration` will allow the liveness endpoint to defer boot-sequence failures for the specified duration period. ([#81969](https://github.com/kubernetes/kubernetes/pull/81969), [@logicalhan](https://github.com/logicalhan))

		Schema: spec.Schema{
			SchemaProps: spec.SchemaProps{
				Description: "Duration is a wrapper around time.Duration which supports correct marshaling to YAML and JSON. In particular, it marshals into strings, which can be used as map keys in json.",
				Type:        metav1.Duration{}.OpenAPISchemaType(),
				Format:      metav1.Duration{}.OpenAPISchemaFormat(),
			},
		},
	}
}

- The kube-controller-manager's deprecated `--experimental-cluster-signing-duration` flag is now removed. Adapt your machinery to use the `--cluster-signing-duration` flag that is available since v1.19. ([#108476](https://github.com/kubernetes/kubernetes/pull/108476), [@ialidzhikov](https://github.com/ialidzhikov))