- To address the possibility of dry-run requests overwhelming admission webhooks that rely on side effects and a reconciliation mechanism, a new field is being added to `admissionregistration.k8s.io/v1beta1.ValidatingWebhookConfiguration` and `admissionregistration.k8s.io/v1beta1.MutatingWebhookConfiguration` so that webhooks can explicitly register as...

- Made `apiextensions-apiserver` binary linking static (also affects the deb and rpm packages). ([#114226](https://github.com/kubernetes/kubernetes/pull/114226), [@saschagrunert](https://github.com/saschagrunert))

evaluated exactly once, in source order, upon entering the "select" statement.
The result is a set of channels to receive from or send to,
and the corresponding values to send.
Any side effects in that evaluation will occur irrespective of which (if any)
communication operation is selected to proceed.
Expressions on the left-hand side of a RecvStmt with a short variable declaration
or assignment are not yet evaluated.

* ReplicationController now shares its underlying controller implementation with ReplicaSet to reduce the maintenance burden going forward. However, they are still separate resources and there should be no externally visible effects from this change. ([#49429](https://github.com/kubernetes/kubernetes/pull/49429), [@enisoc](https://github.com/enisoc))

- Endpoint controller requeues service after an endpoint deletion event occurs to confirm that deleted endpoints are undesired to mitigate the effects of an out of sync endpoint cache. ([#93030](https://github.com/kubernetes/kubernetes/pull/93030), [@swetharepakula](https://github.com/swetharepakula)) [SIG Apps and Network]

  * Note that because any taints you might have created with Kubernetes 1.5 can only affect the scheduling of new pods (the `NoExecute` taint effect is introduced in 1.6), neither the master upgrade nor your running `kubectl taint` to re-create the taints will affect pods that are already running.

will use the local kube-apiserver endpoint for the kubelet when creating a cluster with `kubeadm init` or when joining control plane nodes with `kubeadm join`. Enabling the feature gate also affects the `kubeadm init phase kubeconfig kubelet` phase, where the flag `--control-plane-endpoint` no longer affects the generated kubeconfig `Server` field, but the flag `--apiserver-advertise-address` can now be used for the same purpose. ([#129956](https://github.com/kubernetes/kubernetes/pull/129956), ...

- hyperkube: Use debian-hyperkube-base@v1.1.0 image
  
    A previous release built hyperkube using the debian-hyperkube-base@v1.0.0,
    which was updated to address a CVE in the CNI plugins.
    
    A side-effect of using this new image was that the networking packages
    (namely `iptables`) drifted from the versions used in the kube-proxy images.
  
    The following issues were filed on kube-proxy failures when using hyperkube:

- Controller-manager: the following flags have no effect and would be removed in v1.24:
  - `--port`
  - `--address`
  The insecure port flags `--port` may only be set to 0 now.
- Kube-scheduler: the `--port` and `--address` flags have no effect and would be removed in v1.24.
  The insecure port flags `--port` may only be set to 0 now.

- Official support to build kubernetes with docker-machine / remote docker is removed. This change does not affect building kubernetes with docker locally. ([#97935](https://github.com/kubernetes/kubernetes/pull/97935), [@adeniyistephen](https://github.com/adeniyistephen)) [SIG Release and Testing]