- Kubeadm: remove the automatic detection and matching of cgroup drivers for Docker. For new clusters if you have not configured the cgroup driver explicitly you might get a failure in the `kubelet` on driver mismatch (kubeadm clusters should be using the `systemd` driver). Also remove the `IsDockerSystemdCheck` preflight check (warning) that checks if the Docker cgroup driver is set to `systemd`. Ideally such detection / coordination should be on the side of CRI...

    * This fixed environments where CPU and Memory Accounting were not enabled on the unit that launched the kubelet or docker from reporting the root cgroup when monitoring usage stats for those components.
* New default horizontalpodautoscaler/v1 generator for kubectl autoscale. ([#26775](https://github.com/kubernetes/kubernetes/pull/26775), [@piosz](https://github.com/piosz))

* 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.

- Fixed occasional pod cgroup freeze when using cgroup v1 and systemd driver.

* Add support for SourceIP preservation in Azure LBs ([#36557](https://github.com/kubernetes/kubernetes/pull/36557), [@brendandburns](https://github.com/brendandburns))
* Fix fetching pids running in a cgroup, which caused problems with OOM score adjustments & setting the /system cgroup ("misc" in the summary API). ([#36551](https://github.com/kubernetes/kubernetes/pull/36551), [@timstclair](https://github.com/timstclair))

- If using cgroups v2, then the cgroup aware OOM killer will be enabled for container cgroups via  `memory.oom.group` .  This causes processes within the cgroup to be treated as a unit and killed simultaneously in the event of an OOM kill on any process in the cgroup. ([#117793](https://github.com/kubernetes/kubernetes/pull/117793), [@tzneal](https://github.com/tzneal)) [SIG Apps, Node and Testing]...

Kubelet flag `--enforce-node-allocatable` with a default value of `pods` is added which will make kubelet create a top level cgroup for all pods to enforce Node Allocatable. Optionally, `system-reserved` & `kube-reserved` values can also be specified separated by comma to enforce node allocatable on cgroups specified via `--system-reserved-cgroup` & `--kube-reserved-cgroup` respectively. Note the default value of the latter flags are "". ([#41234](https://github.com/kubernetes/kubernetes/pull/41234),...

- Fixed a bug where the kubelet ephemerally failed with `failed to initialize top level QOS containers: root container [kubepods] doesn't exist`, due to the cpuset cgroup being deleted on cgroup v2 with systemd cgroup manager.
   ([#125923](https://github.com/kubernetes/kubernetes/pull/125923), [@haircommander](https://github.com/haircommander)) [SIG Node and Testing]

```

* Fix fetching pids running in a cgroup, which caused problems with OOM score adjustments & setting the /system cgroup ("misc" in the summary API). ([#36614](https://github.com/kubernetes/kubernetes/pull/36614), [@timstclair](https://github.com/timstclair))

				"application/vnd.chemdraw+xml",
				"application/vnd.chipnuts.karaoke-mmd",
				"application/vnd.cinderella",
				"application/vnd.cirpack.isdn-ext",
				"application/vnd.claymore",
				"application/vnd.clonk.c4group",
				"application/vnd.commerce-battelle",
				"application/vnd.commonspace",
				"application/vnd.contact.cmsg",
				"application/vnd.cosmocaller",
				"application/vnd.crick.clicker",