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

- 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))

        if (opLambda != null) {
            opLambda.callback(builder);
        }
    }

    public void setGroups_Regexp(String groups) {
        setGroups_Regexp(groups, null);
    }

    public void setGroups_Regexp(String groups, ConditionOptionCall<RegexpQueryBuilder> opLambda) {
        RegexpQueryBuilder builder = regRegexpQ("groups", groups);

- 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]

* 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.

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),...

- 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...

### Quality of Service for memory resources

- Fix handling of aws-load-balancer-security-groups annotation. Security-Groups assigned with this annotation are no longer modified by kubernetes which is the expected behaviour of most users. Also no unnecessary Security-Groups are created anymore if this annotation is used. ([#83446](https://github.com/kubernetes/kubernetes/pull/83446), [@Elias481](https://github.com/Elias481)) [SIG...

*   Code generation for CRD and User API server types is improved with the addition of two new scripts to k8s.io/code-generator: `generate-groups.sh` and `generate-internal-groups.sh`. ([#52186](https://github.com/kubernetes/kubernetes/pull/52186),[ @sttts](https://github.com/sttts))