* Add `--enable-admission-plugins` `--disable-admission-plugins` flags and deprecate `--admission-control`. When using the separate flag, the order in which they're specified doesn't matter.  ([#58123](https://github.com/kubernetes/kubernetes/pull/58123), [@hzxuzhonghu](https://github.com/hzxuzhonghu))

- Kubeadm: deprecate self-hosting support. The experimental command "kubeadm alpha self-hosting" is now deprecated and will be removed in a future release. ([#95125](https://github.com/kubernetes/kubernetes/pull/95125), [@neolit123](https://github.com/neolit123)) [SIG...

 - Remove alpha `CSIMigrationXXComplete` flag and add alpha `InTreePluginXXUnregister` flag. Deprecate `CSIMigrationvSphereComplete` flag and it will be removed in v1.22. ([#98243](https://github.com/kubernetes/kubernetes/pull/98243), [@Jiawei0227](https://github.com/Jiawei0227))

- Deprecate `--record` flag in `kubectl`. The `--record` flag is being replaced with the [mechanism](https://github.com/kubernetes/enhancements/tree/master/keps/sig-cli/859-kubectl-headers) which annotates HTTP requests with kubectl command details. ([#1028...

* retry oauth token fetch in gce cloudprovider ([#32021](https://github.com/kubernetes/kubernetes/pull/32021), [@mikedanese](https://github.com/mikedanese))
* Deprecate the old cbr0 and flannel networking modes ([#31197](https://github.com/kubernetes/kubernetes/pull/31197), [@freehan](https://github.com/freehan))

This release does *not* deprecate the v1 HorizontalPodAutoscaler API.

### Generic Ephemeral Volume feature graduates to GA

The generic ephemeral volume feature moved to GA in 1.23.

## Kubefed

* Deprecate the `--secret-name` flag from `kubefed join`, instead generating the secret name arbitrarily. ([#42513](https://github.com/kubernetes/kubernetes/pull/42513), [@perotinus](https://github.com/perotinus))


### **Kubernetes API**

- Deprecate apiserver_storage_objects and replace it with apiserver_resource_objects metric using labels consistent with other metrics ([#132965](https://github.com/kubernetes/kubernetes/pull/132965), [@serathius](https://github.com/serathius)) [SIG API Machinery,...

  and removed `--short` flag entirely. ([#116720](https://github.com/kubernetes/kubernetes/pull/116720), [@soltysh](https://github.com/soltysh))

* Add --request-timeout to kube-apiserver to make global request timeout configurable. ([#51415](https://github.com/kubernetes/kubernetes/pull/51415), [@jpbetz](https://github.com/jpbetz))