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...

* 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))

   ([#122724](https://github.com/kubernetes/kubernetes/pull/122724), [@nayihz](https://github.com/nayihz))
- In the Pod API, setting the alpha `procMount` field to `Unmasked` in a container now required setting `spec.hostUsers=false` as well.
   ([#123520](https://github.com/kubernetes/kubernetes/pull/123520), [@haircommander](https://github.com/haircommander))

### 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. 

* 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))

* 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))

   consuming metrics via an aggregated version of the resource metrics API.

   - In version 1.8, enable this behavior by setting the
     `--horizontal-pod-autoscaler-use-rest-clients` flag to `true`.

   - In version 1.9, this behavior will be enabled by default, and must be explicitly
     disabled by setting the `--horizontal-pod-autoscaler-use-rest-clients` flag to `false`.

### Cluster Lifecycle

- Avoid caching the Azure VMSS instances whose network profile is nil ([#100948](https://github.com/kubernetes/kubernetes/pull/100948), [@feiskyer](https://github.com/feiskyer)) [SIG Cloud Provider]
- Azure: avoid setting cached Sku when updating VMSS and VMSS instances ([#102005](https://github.com/kubernetes/kubernetes/pull/102005), [@feiskyer](https://github.com/feiskyer)) [SIG Cloud Provider]

  
  kubelet also ignores an error during opening `/dev/kmsg`.
  This feature gate also allows kube-proxy to ignore an error during setting `RLIMIT_NOFILE`.
  

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