* 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: Removes defaulting of CSI file system type to ext4. All the production drivers listed under https://kubernetes-csi.github.io/docs/drivers.html were inspected and should not be impacted after this change. If you are using a driver not in that list, please test the drivers on an updated test cluster first. ([#65499](https://github.com/kubernetes/kubernetes/pull/65499), [@krunaljain](https://github.com/krunaljain))

Fixed kubelet so it would no longer crash when a DRA(Dynamic Resource Allocation) driver returns a nil as part of the Node(Un)PrepareResources response instead of an empty struct (Did not affect drivers written in Go, first showed up with a driver written in Rust). returns a nil as part of the Node(Un)PrepareResources response instead of an empty struct (did not affect drivers written in Go, first showed up with a driver written in Rust). ([#124091](https://github.com/kubernetes/kubernetes/pull/124091),...

#### **Other**

*   Pod Security Policy can now manage access to specific FlexVolume drivers ([#53179](https://github.com/kubernetes/kubernetes/pull/53179),[ @wanghaoran1988](https://github.com/wanghaoran1988))

    * 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

### Deprecation

- Added support for vSphere in-tree volumes migration to vSphere CSI driver. The in-tree vSphere Volume plugin will be deprecated and removed in a future release.
  

### Action Required

* ACTION REQUIRED: Removes defaulting of CSI file system type to ext4. All the production drivers listed under https://kubernetes-csi.github.io/docs/drivers.html were inspected and should not be impacted after this change. If you are using a driver not in that list, please test the drivers on an updated test cluster first. ``` ([#65499](https://github.com/kubernetes/kubernetes/pull/65499), [@krunaljain](https://github.com/krunaljain))

* Docker versions 1.10.3, 1.11.2, 1.12.6 have been validated
  * Docker version 1.12.6 known issues
    * overlay2 driver not fully supported
    * live-restore not fully supported
    * no shared pid namespace support
  * Docker version 1.11.2 known issues
    * Kernel crash with Aufs storage driver on Debian Jessie ([#27885](https://github.com/kubernetes/kubernetes/issues/27885))

- The in-tree cloud provider for vSphere has been deprecated and removed. Users are advised to utilize the external cloud provider and CSI driver available at https://github.com/kubernetes/cloud-provider-vsphere. ([#122937](https://...

#### Storage