- Shared PID namespace, live-restore, and overlay2 were validated.

    - **Known issues**

        - The default iptables FORWARD policy was changed from ACCEPT to
          DROP, which causes outbound container traffic to stop working by
          default. See
          [#40182](https://github.com/kubernetes/kubernetes/issues/40182) for
          the workaround.

vSphere. ([#59328](https://github.com/kubernetes/kubernetes/pull/59328), [@divyenpatel](https://github.com/divyenpatel))

* Emit number of bound and unbound persistent volumes as Metrics. This PR adds four kinds of Volume Metrics for kube-controller-manager: bound PVC numbers, unbound PVC numbers, bound PV numbers and unbound PV numbers. The PVC metrics use namespace as dimension and the PV metrics use StorageClassName as its dimension. With these metrics we can better monitor the use...

  `storage_count_attachable_volumes_in_use`
  `attachdetach_controller_total_volumes`
  `pv_collector_bound_pv_count`
  `pv_collector_unbound_pv_count`
  `pv_collector_bound_pvc_count`
  `pv_collector_unbound_pvc_count`
  ([#84896](https://github.com/kubernetes/kubernetes/pull/84896), [@RainbowMango](https://github.com/RainbowMango))
- Following metrics have been turned off:

## Changelog since v1.18.8

## Changes by Kind

### Bug or Regression

- "unbound immediate PersistentVolumeClaims" causes UnschedulableAndUnresolvable status rather than an Error in the scheduler. ([#93892](https://github.com/kubernetes/kubernetes/pull/93892), [@ahg-g](https://github.com/ahg-g)) [SIG Apps and Storage]

- Fixed a concurrent map access in `TopologyCache`'s `HasPopulatedHints` method. ([#118189](https://github.com/kubernetes/kubernetes/pull/118189), [@Miciah](https://github.com/Miciah))
- Fixed a regression (`CLIENTSET_PKG: unbound variable`) when invoking deprecated `generate-groups.sh` script. ([#120877](https://github.com/kubernetes/kubernetes/pull/120877), [@soltysh](https://github.com/soltysh))