for a certain priority level configuration object via the two newly introduced fields `lendablePercent`, and
  `borrowingLimitPercent` located under the `.spec.limited` field of the designated priority level.
  This change added the following metrics:
    - `apiserver_flowcontrol_nominal_limit_seats`: Nominal number of execution seats configured for each priority level

- In the event that more than one IngressClass is designated "default", the DefaultIngressClass admission controller will choose one rather than fail. ([#110974](https://github.com/kubernetes/kubernetes/pull/110974), [@kidddddddddddddddddddddd](https://github.com/kidddddddddddddddddddddd)) [SIG Network]

As an alpha feature, Kubernetes v1.22 can use the cgroups v2 API to control memory allocation and isolation. This feature is designed to improve workload and node availability when there is contention for memory resources.

### API changes and improvements for ephemeral containers

- Kubeadm: the `--feature-gates` flag is deprecated and no-op for `kubeadm upgrade apply/plan`, and it will be removed in a future release. The upgrade workflow is not designed to reconfigure the cluster. Please edit the 'featureGates' field of ClusterConfiguration which is defined in the kube-system/kubeadm-config ConfigMap instead. ([#125797](https://github.com/kubernetes/kubernetes/pull/125797), [@SataQiu](https://github.com/SataQiu))...