administrators will be able to place limits by using the new kubelet command line parameter --pod-max-pids. Note that since this is a alpha feature they will need to enable the "SupportPodPidsLimit" feature. By default, we do not set any maximum limit, If an administrator wants to enable this, they should enable SupportPodPidsLimit=true in the --feature-gates= parameter to kubelet and specify the limit using the --pod-max-pids parameter. The limit set is the total count of all processes running in all containers...

- `diskformat` storage class parameter for in-tree vSphere volume plugin is deprecated as of v1.21 release. Please consider updating storageclass and remove `diskformat` parameter. vSphere CSI Driver does not support diskformat storageclass parameter.
  

* Fix mounting of UNIX sockets(and other special files) in subpaths ([#61480](https://github.com/kubernetes/kubernetes/pull/61480), [@gnufied](https://github.com/gnufied))
* Fix GCE etcd scripts to pass in all required parameters for the etcd migration utility to correctly perform HA upgrades and downgrades ([#61957](https://github.com/kubernetes/kubernetes/pull/61957), [@jpbetz](https://github.com/jpbetz))

* Created a new `dryRun` query parameter for mutating endpoints. If the parameter is set, then the query will be rejected, as the feature is not implemented yet. This will allow forward compatibility with future clients; otherwise, future clients talking with older apiservers might end up modifying a resource even if they include the `dryRun` query parameter. ([#63557](https://github.com/kubernetes/kubernetes/pull/63557), [@apelisse](https://...

- The `IngressClassNamespacedParams` feature gate has graduated to beta and is enabled by default. This means IngressClass resource will now have two new fields - `spec.paramters.namespace` and `spec.parameters.scope`. ([#101711](https://github.com/kubernetes/kubernetes/pull/101711), [@hbagdi](https://github.com/hbagdi))

    ```
    Storage class spec:
    kind: StorageClass
    apiVersion: storage.k8s.io/v1
    metadata:
      name: fastpolicy1
    provisioner: kubernetes.io/vsphere-volume
    parameters:
        diskformat: zeroedthick
        storagePolicyName: vSAN Default Storage Policy
    allowedTopologies:
    - matchLabelExpressions:
      - key: failure-domain.beta.kubernetes.io/zone
        values:

- The deprecated flag `--lock-object-namespace` and `--lock-object-name` have been removed from kube-scheduler. Please use `--leader-elect-resource-namespace` and `--leader-elect-resource-name` or ComponentConfig instead to configure those parameters. ([#119130](https://github.com/kubernetes/kubernetes/pull/119130), [@SataQiu](https://github.com/SataQiu)) [SIG Scheduling]

* Fixed pod cleanup when /var/lib/kubelet is a symlink. ([#68741](https://github.com/kubernetes/kubernetes/pull/68741), [@jsafrane](https://github.com/jsafrane))
* Add "only_cpu_and_memory" GET parameter to /stats/summary http handler in kubelet. If parameter is true then only cpu and memory will be present in response. ([#67829](https://github.com/kubernetes/kubernetes/pull/67829), [@krzysztof-jastrzebski](https://github.com/krzysztof-jastrzebski))

  * You must install the Ceph CSI driver (rbd.csi.ceph.com), v3.5.0 or above, into your Kubernetes cluster.

- Fixed a bug where dry-run is not honored for pod/eviction sub-resource. ([#76969](https://github.com/kubernetes/kubernetes/pull/76969), [@apelisse](https://github.com/apelisse))

- DeleteOptions parameters for deletecollection endpoints are now published in the OpenAPI spec. ([#77843](https://github.com/kubernetes/kubernetes/pull/77843), [@roycaihw](https://github.com/roycaihw))