Two alpha features were also added in this release.

The RuntimeClass alpha feature enables a node to surface multiple runtime options to support a variety of workload types.  Examples include native linux containers, and “sandboxed” containers that isolate the container from the host kernel.

    * [StorageOS](http://www.storageos.com) can be used as a storage provider for Kubernetes.  With StorageOS, capacity from local or attached storage is pooled across the cluster, providing converged infrastructure for cloud-native applications.
* CRI has been moved to package `pkg/kubelet/apis/cri/v1alpha1/runtime`. ([#47113](https://github.com/kubernetes/kubernetes/pull/47113), [@feiskyer](https://github.com/feiskyer))

- Kubelet podresources API now provides the information about active pods only. ([#79409](https://github.com/kubernetes/kubernetes/pull/79409), [@takmatsu](https://github.com/takmatsu)) [SIG Node]

- in an `--encryption-provider-config` config file, an explicit `cacheSize: 0` parameter previously silently defaulted to caching 1000 keys. In Kubernetes 1.18, this now returns a config validation error. To disable caching, you can specify a negative cacheSize value in Kubernetes 1.18+.

### Bug or Regression

- Fix panic if there are more terminating pods than active pods ([#122267](https://github.com/kubernetes/kubernetes/pull/122267), [@kannon92](https://github.com/kannon92)) [SIG Apps]

    *   Extends the device plugin checkpoint data to record registered resources so that we can finish resource removing devices even upon kubelet restarts.
    *   Passes sourcesReady from kubelet to the device plugin to avoid removing inactive pods during the grace period of kubelet restart.

### Windows

* kubelet and kube-proxy can now be run as native Windows services. ([#60144](https://github.com/kubernetes/kubernetes/pull/60144), [@alinbalutoiu](https://github.com/alinbalutoiu))

* kubectl built for darwin from darwin now enables cgo to use the system-native C libraries for DNS resolution. Cross-compiled kubectl (e.g. from an official kubernetes release) still uses the go-native netgo DNS implementation.  ([#64219](https://github.com/kubernetes/kubernetes/pull/64219), [@ixdy](https://github.com/ixdy))

  The `skippedScorePlugins` number might be greater than `enabledScorePlugins`, 
  so when initializing a slice the cap(len(skippedScorePlugins) - len(enabledScorePlugins)) is negative, 
  which is not allowed. ([#121666](https://github.com/kubernetes/kubernetes/pull/121666), [@kerthcet](https://github.com/kerthcet)) [SIG Scheduling]

- Set kubelet option `--volume-stats-agg-period` to negative value to disable volume calculations. ([#96675](https://github.com/kubernetes/kubernetes/pull/96675), [@pacoxu](https://github.com/pacoxu)) [SIG Node]

### Failing Test