* configuration scripts to allow configuration of signing duration of
    * certificates issued via the Certificate Signing Request API.

* StatefulSets now include an alpha scaling feature accessible by setting the `spec.podManagementPolicy` field to `Parallel`.  The controller will not wait for pods to be ready before adding the other pods, and will replace deleted pods as needed.  Since parallel scaling creates pods out of order, you cannot depend on predictable membership changes within your set. ([#44899](https://github.com/kuberne...

- The kube-controller-manager managed signers can now have distinct signing certificates and keys.  See the help about `--cluster-signing-[signer-name]-{cert,key}-file`.  `--cluster-signing-{cert,key}-file` is still the default. ([#90822](https://github.com/kubernetes/kubernetes/pull/90822), [@deads2k](https://github.com/deads2k)) [SIG API Machinery, Apps and Auth]

*   `etcd2` as a backend is deprecated and support will be removed in Kubernetes 1.13 or 1.14.

### **Auth**

*   Default controller-manager options for `--cluster-signing-cert-file` and `--cluster-signing-key-file` are deprecated and will be removed in a future release. ([#54495](https://github.com/kubernetes/kubernetes/pull/54495),[ @mikedanese](https://github.com/mikedanese))

- Kubeadm: warn but do not error out on missing "ca.key" files for root CA, front-proxy CA and etcd CA, during "kubeadm join --control-plane" if the user has provided all certificates, keys and kubeconfig files which require signing with the given CA keys. ([#94988](https://github.com/kubernetes/kubernetes/pull/94988), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

### Other (Cleanup or Flake)

* CRI: respect container's stopping timeout. ([#44998](https://github.com/kubernetes/kubernetes/pull/44998), [@feiskyer](https://github.com/feiskyer))
* Fix problems with scaling up the cluster when unschedulable pods have some persistent volume claims. ([#44860](https://github.com/kubernetes/kubernetes/pull/44860), [@mwielgus](https://github.com/mwielgus))

- Added CEL expressions to `v1alpha1 AuthenticationConfiguration`. ([#121078](https://github.com/kubernetes/kubernetes/pull/121078), [@aramase](https://github.com/aramase))
- Added Windows support for InPlace Pod Vertical Scaling feature. ([#112599](https://github.com/kubernetes/kubernetes/pull/112599), [@fabi200123](https://github.com/fabi200123)) [SIG Autoscaling, Node, Scalability, Scheduling and Windows]

- Azure virtual machine scale sets (VMSS) allow you to create and manage identical load balanced VMs that automatically increase or decrease based on demand or a set schedule.
- With this new stable feature, Kubernetes supports the scaling of containerized applications with Azure VMSS, including the ability to integrate it with cluster-autoscaler to automatically adjust the size of the Kubernetes clusters based on the same conditions.

### SIG-cli

* Removed alpha functionality that allowed the controller manager to approve kubelet server certificates. This functionality should be replaced by automating validation and approval of node server certificate signing requests. ([#62471](https://github.com/kubernetes/kubernetes/pull/62471), [@mikedanese](https://github.com/mikedanese))

#### Graduated to Stable/GA

- Kubeadm: warn but do not error out on missing "ca.key" files for root CA, front-proxy CA and etcd CA, during "kubeadm join --control-plane" if the user has provided all certificates, keys and kubeconfig files which require signing with the given CA keys. ([#94988](https://github.com/kubernetes/kubernetes/pull/94988), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

### Other (Cleanup or Flake)