## Changes by Kind

### Deprecation

- ACTION REQUIRED: `failCgroupV1` will be set to true from 1.35. 
  This means that nodes will not start on a cgroup v1 by default. This puts cgroup v1 into a deprecated state. ([#134298](https://github.com/kubernetes/kubernetes/pull/134298), [@kannon92](https://github.com/kannon92))

 - 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...

* 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.

- 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]

- When specifying `--(kube|system)-reserved-cgroup`, with `--cgroup-driver=systemd`, it is now possible to use the fully qualified cgroupfs name (i.e. `/test-cgroup.slice`). ([#78793](https://github.com/kubernetes/kubernetes/pull/78793), [@mattjmcnaughton](https://github.com/mattjmcnaughton))

### SIG Node

- Fixed a bug in previous releases where a pod could be placed inside another pod's cgroup when specifying --cgroup-root ([#70678](https://github.com/kubernetes/kubernetes/pull/70678), [@dashpole](https://github.com/dashpole))

- Promoted CRI communication of the cgroup driver mechanism to beta. The `KubeletCgroupDriverFromCRI` feature gate is now in beta and enabled by default. This allows the kubelet to query the container runtime using CRI to determine the mechanism for cgroup management. If the container runtime doesn't support this, the kubelet falls back to using the configuration file (you can also use the deprecated `--cgroup-driver` command line argument). ([#125828](https://github.com...