* The Kubelet's deprecated `--allow-privileged` flag now defaults to true. This enables users to stop setting `--allow-privileged` in order to transition to `PodSecurityPolicy`. Previously, users had to continue setting `--allow-privileged`, because the default was false. ([#63442](https://github.com/kubernetes/kubernetes/pull/63442), [@mtaufen](https://github.com/mtaufen))

streaming requests on a different host interface than what the apiserver makes requests on (only the case if not using the built-in dockershim & setting the kubelet flag `--redirect-container-streaming=true`), then these requests will be broken. In that case, the feature can be temporarily disabled until the node configuration is corrected. We suggest setting `--redirect-container-streaming=false` on the kubelet to avoid issues.([#72552](https://github.com/kubernetes/kubernetes/pull/72552), [@tallc...

### kubeadm
* Quite a few flags been renamed or removed.  Those options that are removed as flags can still be accessed via the config file.  Most notably this includes external etcd settings and the option for setting the cloud provider on the API server.  The [kubeadm reference documentation](https://kubernetes.io/docs/admin/kubeadm/) is up to date with the new flags.

### Other Deprecations

* Introduce a new flag `--keepalive` for kubectl proxy to allow setting keep-alive period for long-running request. ([#63793](https://github.com/kubernetes/kubernetes/pull/63793), [@hzxuzhonghu](https://github.com/hzxuzhonghu))

### Non-recursive Volume Ownership (FSGroup) graduates to Beta

By default, the `fsgroup` setting, if specified, recursively updates permissions for every file in a volume on every mount. This can make mount, and pod startup, very slow if the volume has many files. 

  that was previously rejected by the VolemeZone plugin if  addition/update of node, 
  addition/update of PV, addition/update of PVC, or addition of SC matches pod's topology settings. ([#124996](https://github.com/kubernetes/kubernetes/pull/124996), [@Gekko0114](https://github.com/Gekko0114)) [SIG Scheduling and Storage]
- Kube-scheduler implements scheduling hints for the VolumeZone plugin.

- The `--certificate-authority` flag now correctly overrides existing skip-TLS or CA data settings in the kubeconfig file ([#83547](https://github.com/kubernetes/kubernetes/pull/83547), [@liggitt](https://github.com/liggitt))
### Cloud Provider

* When the `PodShareProcessNamespace` alpha feature is enabled, setting `pod.Spec.ShareProcessNamespace` to `true` will cause a single process namespace to be shared between all containers in a pod. ([#58716](https://github.com/kubernetes/kubernetes/pull/58716), [@verb](https://github.com/verb))

  updated. ([#120492](https://github.com/kubernetes/kubernetes/pull/120492), [@cezarygerard](https://github.com/cezarygerard))

deprecated, and will be removed in a future release. The default behavior (proxy streaming requests through the kubelet) will be the only supported option. If you are setting `--redirect-container-streaming=true`, then you must migrate off this configuration. The flag will no longer be able to be enabled starting in v1.20. If you are not setting the flag, no action is necessary. ([#88290](https://github.com/kubernetes/kubernetes/pull/88290), [@tallclair](https://github.com/tallclair)) [SIG API Machinery...