* Fix a scalability issue where high rates of event writes degraded etcd performance. ([#64539](https://github.com/kubernetes/kubernetes/pull/64539), [@ccding](https://github.com/ccding))

  - `priority_level_request_count_watermarks` is removed.
  - `read_vs_write_request_count_samples` is replaced with `read_vs_write_current_requests`, which samples every nanosecond rather than every second; the new metric, like the old one, measures utilization when the max-in-flight filter is used and number of requests when the API Priority and Fairness filter is used.

    * Docker version 1.12.6 known issues

        * overlay2 driver not fully supported

        * live-restore not fully supported

        * no shared pid namespace support

    * Docker version 1.11.2 known issues

* Fixed a bug in the CSI metrics that does not return not supported error when a CSI driver does not support metrics. ([#79851](https://github.com/kubernetes/kubernetes/pull/79851), [@jparklab](https://github.com/jparklab))
* Fix a bug in server printer that could cause kube-apiserver to panic. ([#79349](https://github.com/kubernetes/kubernetes/pull/79349), [@roycaihw](https://github.com/roycaihw))

- Unlocked the `CSIMigrationvSphere` feature gate. The change allow users to continue using the in-tree vSphere driver,pending a vSphere CSI driver release that has with GA support for Windows, XFS, and raw block access. ([#116396](https://github.com/kubernetes/kubernetes/pull/116396), [@msau42](https://github.com/msau42)) [SIG Storage]

### Bug or Regression

* kubeadm now detects the Docker cgroup driver and starts the kubelet with the matching driver. This eliminates a common error experienced by new users in when the Docker cgroup driver is not the same as the one set for the kubelet due to different Linux distributions setting different cgroup drivers for Docker, making it hard to start the kubelet properly.

* remove iSCSI volume storage cleartext secrets in logs ([#81215](https://github.com/kubernetes/kubernetes/pull/81215), [@zouyee](https://github.com/zouyee))
* Fix a bug in server printer that could cause kube-apiserver to panic. ([#79349](https://github.com/kubernetes/kubernetes/pull/79349), [@roycaihw](https://github.com/roycaihw))

- Fixed migration of in-tree vSphere volumes to the CSI driver. ([#122341](https://github.com/kubernetes/kubernetes/pull/122341), [@jsafrane](https://github.com/jsafrane)) [SIG Storage]