* Bug fixes

  * Fixes issue with Flexvolume, introduced in 1.6.0, where drivers without an attacher would fail (node indefinitely waiting for attach). A driver API addition is introduced: drivers that don't implement attach should return attach: false on init. ([#47503](https://github.com/kubernetes/kubernetes/pull/47503), [@chakri-nelluri](https://github.com/chakri-nelluri))

    * ACTION REQUIRED: the alpha CRDs are no longer used and drivers will need to be updated to use the beta APIs.
    * The support for `_` in the CSI driver name will be dropped as the CSI Spec does not allow that. 

### Other notable changes

### Feature

- 'Added selector validation to `HorizontalPodAutoscaler`: when multiple HPAs
  select the same set of Pods, scaling now will be disabled for those HPAs with
  the reason `AmbiguousSelector`. This change also covers a case when multiple HPAs
  point to the same deployment.'
   ([#112011](https://github.com/kubernetes/kubernetes/pull/112011), [@pbeschetnov](https://github.com/pbeschetnov))

   ([#123508](https://github.com/kubernetes/kubernetes/pull/123508), [@saschagrunert](https://github.com/saschagrunert))
- Dynamic Resource Allocation: DRA drivers can now use "structured parameters" to let the scheduler handle claim allocation.
   ([#123516](https://github.com/kubernetes/kubernetes/pull/123516), [@pohly](https://github.com/pohly))

* Flex volume plugin is updated to support attach/detach interfaces. It broke backward compatibility. Please update your drivers and implement the new callouts.  ([#41804](https://github.com/kubernetes/kubernetes/pull/41804), [@chakri-nelluri](https://github.com/chakri-nelluri))

## Notable Features

- Some of the in-tree storage drivers indicate support for the `MetricsProvider` interface, but fail to configure this for BlockMode volumes. With a recent change, `Kubelet` will call `GetMetrics()` for BlockMode volumes, and the in-tree drivers that miss the support cause a Go panic. Now the in-tree storage drivers that support BlockMode volumes, will return the Capacity of the volume in the `GetMetrics()` call. ([#1015...

### Security Improvements for CSI Drivers (Alpha)

    - [Skip Volume Ownership change graduates to GA](#skip-volume-ownership-change-graduates-to-ga)
    - [Allow CSI drivers to opt-in to volume ownership and permission change graduates to GA](#allow-csi-drivers-to-opt-in-to-volume-ownership-and-permission-change-graduates-to-ga)
    - [PodSecurity graduates to Beta](#podsecurity-graduates-to-beta)

- This release added support for `NodeExpandSecret` for CSI driver client which enables the CSI drivers to make use of this secret while performing node expansion operation based on the user request. Previously there was no secret  provided as part of the `nodeexpansion` call, thus CSI drivers did not make use of the same while expanding the volume at the node side. ([#105963](https://github.com/kubernetes/kubernetes/pull/105963), [@zhucan](...

### CSI Proxy for Windows

The CSI Proxy for Windows is being promoted to beta along with the 1.19 release. This CSI Proxy enables CSI Drivers to run on Windows by allowing containers in Windows to perform privileged storage operations. At beta, the CSI Proxy for Windows supports storage drivers using direct attached disks and SMB.

### Dashboard v2