- 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)

* PodSecurityPolicy: when multiple policies allow a submitted pod, priority is given to ones which do not require any fields in the pod spec to be defaulted. If the pod must be defaulted, the first policy (ordered by name) that allows the pod is used. ([#52849](https://github.com/kubernetes/kubernetes/pull/52849), [@liggitt](https...

## Changelog since v1.18.18

## Changes by Kind

### API Change

- We have added a new Priority & Fairness rule that exempts all probes (/readyz, /healthz, /livez) to prevent 
  restarting of "healthy" kube-apiserver instance(s) by kubelet. ([#101114](https://github.com/kubernetes/kubernetes/pull/101114), [@tkashem](https://github.com/tkashem)) [SIG API Machinery]

### Bug or Regression

- Fixed a regression in kube-proxy where it might refuse to start if given
  single-stack IPv6 configuration options on a node that has both IPv4 and
  IPv6 IPs. ([#121008](https://github.com/kubernetes/kubernetes/pull/121008), [@danwinship](https://github.com/danwinship)) [SIG Network]

* Update to go1.10.8 ([#73329](https://github.com/kubernetes/kubernetes/pull/73329), [@ixdy](https://github.com/ixdy))
* Allow for watching objects larger than 1MB given etcd accepts objects of size up to 1.5MB ([#72053](https://github.com/kubernetes/kubernetes/pull/72053), [@wojtek-t](https://github.com/wojtek-t))

- We have added a new Priority & Fairness rule that exempts all probes (/readyz, /healthz, /livez) to prevent 
  restarting of "healthy" kube-apiserver instance(s) by kubelet. ([#101111](https://github.com/kubernetes/kubernetes/pull/101111), [@tkashem](https://github.com/tkashem)) [SIG API Machinery]

### Feature

*   If multiple PodSecurityPolicy objects allow a submitted pod, priority is given to policies that do not require default values for any fields in the pod spec. If default values are required, the first policy ordered by name that allows the pod is used. ([#52849](https://github.com/kubernetes/kubernetes/pull/52849),[ @liggitt]...

* RBAC: The system:kubelet-api-admin cluster role can be used to grant full access to the kubelet API  so integrators can grant this role to the --kubelet-client-certificate credential given to the apiserver. ([#57128](https://github.com/kubernetes/kubernetes/pull/57128), [@liggitt](https://github.com/liggitt))

- [alpha: kubectl apply --prune --applyset] Enabled certain custom resources (CRs) to be used as `ApplySet` parent objects. To enable this for a given CR, apply the label `applyset.kubernetes.io/is-parent-type: true` to the CustomResourceDefinition (CRD) that defines it. ([#116353](https://github.com/kubernetes/kubernetes/pull/116353), [@KnVerey](https://github.com/KnVerey))

## Changelog since v1.11.6

### Other notable changes

* Allow for watching objects larger than 1MB given etcd accepts objects of size up to 1.5MB ([#72053](https://github.com/kubernetes/kubernetes/pull/72053), [@wojtek-t](https://github.com/wojtek-t))