* iSCSI Persistent Volume Sources can now reference CHAP Secrets in namespaces other than the namespace of the bound Persistent Volume Claim ([#51530](https://github.com/kubernetes/kubernetes/pull/51530), [@rootfs](https://github.com/rootfs))

  
  vSphere releases less than 67u3 are deprecated as of v1.21. Please consider upgrading vSphere to 67u3 or above. vSphere CSI Driver requires minimum vSphere 67u3.
  

* PersistentVolume flexVolume sources can now reference secrets in a namespace other than the PersistentVolumeClaim's namespace. ([#56460](https://github.com/kubernetes/kubernetes/pull/56460), [@liggitt](https://github.com/liggitt))

### Windows

  Depending on the value returned from QueueingHintFn, the scheduling queue changes how it queues each Pod:
  - if more than one QueueingHintFn returns QueueImmediately, it queues Pod to activeQ.
  - If no QueueingHintFn returns QueueImmediately and more than one plugin returns QueueAfterBackoff, it queues Pod to backoffQ if Pod is backing off, or to activeQ if Pod's backoff has already finished.

  - Kube-scheduler can run more than one scheduling profile. Given a pod, the profile is selected by using its `.spec.schedulerName`. ([#88285](https://github.com/kubernetes/kubernetes/pull/88285), [@alculquicondor](https://github.com/alculquicondor)) [SIG Apps, Scheduling and Testing]

- The kubelet now creates an iptables chain named `KUBE-IPTABLES-HINT` in
  the `mangle` table. Containerized components that need to modify iptables
  rules in the host network namespace can use the existence of this chain
  to more-reliably determine whether the system is using iptables-legacy or

For example, a plugin that implements Score and Filter extensions can be simultaneously enabled for both.
This means entire plugins can be enabled and disabled without having to manually edit individual extension point settings.
These extension points can now be abstracted away due to their irrelevance for most users.

### CSI Migration updates

out-of-memory event occurs. This implementation has shortcomings: for `Guaranteed` pods, memory can not be fully reserved, and the page cache is at risk of being recycled. For `Burstable` pods, overcommitting memory (setting `request` less than `limit` ) could increase the risk of a container being killed when the Linux kernel detects an out of memory condition.

As an alpha feature, Kubernetes v1.22 can use the cgroups v2 API to control memory allocation and isolation. This feature is designed...

ference/scheduling/config) feature allows you to tune the algorithms and other settings of the kube-scheduler. You can easily enable or disable specific functionality (contained in plugins) in selected scheduling phases without having to rewrite the rest of the configuration. Furthermore, a single kube-scheduler instance can serve different configurations, called profiles. Pods can select the profile they want to be scheduled under via the `.spec.schedulerName` field.

### CSI Migration...

- UDP and SCTP protocols can left stale connections that need to be cleared to avoid services disruption, but they can cause problems that are hard to debug.