* Introduce a RuntimeClass v1beta1 API. This new beta API renames `runtimeHandler` to `handler`, makes it a required field, and cuts out the spec (handler is a top-level field).
* Transition CSINodeInfo and CSIDriver alpha CRDs to in-tree CSINode and CSIDriver core storage v1beta1 APIs. ([#74283](https://github.com/kubernetes/kubernetes/pull/74283), [@xing-yang](https://github.com/xing-yang))

### CSIDriver policy for FSGroup graduates to Beta

The FSGroup's CSIDriver Policy is now beta in 1.20. This allows CSIDrivers to explicitly indicate if they want Kubernetes to manage permissions and ownership for their volumes via `fsgroup`. 

### Security Improvements for CSI Drivers (Alpha)

- Volume Cloning: Duplicate a PersistentVolumeClaim and underlying storage volume using the Kubernetes API via CSI.
- CSIDriver Kubernetes API Object: Simplifies CSI driver discovery and allows CSI Drivers to customize Kubernetes behavior.

SIG Storage is also introducing the following new storage features as alpha in Kubernetes 1.18:

- CSIPersistentVolume feature, i.e. PersistentVolumes with CSIPersistentVolumeSource, is GA.  ([#69929](https://github.com/kubernetes/kubernetes/pull/69929), [@jsafrane](https://github.com/jsafrane))
- Fixed CSIDriver API object to allow missing fields. ([#69331](https://github.com/kubernetes/kubernetes/pull/69331), [@jsafrane](https://github.com/jsafrane))

- Users are now allowed to mutate `FSGroupPolicy` and `PodInfoOnMount` in `CSIDriver.Spec`. ([#116209](https://github.com/kubernetes/kubernetes/pull/116209), [@haoruan](https://github.com/haoruan))

- The `CSIDriver.Spec.StorageCapacity` can now be modified. ([#101789](https://github.com/kubernetes/kubernetes/pull/101789), [@pohly](https://github.com/pohly))

* Fixed panic on iSCSI volume tear down. ([#69140](https://github.com/kubernetes/kubernetes/pull/69140), [@jsafrane](https://github.com/jsafrane))
* Fixed CSIDriver API object to allow missing fields. ([#69331](https://github.com/kubernetes/kubernetes/pull/69331), [@jsafrane](https://github.com/jsafrane))

* a CSI driver that supports ephemeral inline volumes must explicitly declare that by providing a CSIDriver object where the new "mode" field is set to "ephemeral" or "persistent+ephemeral" ([#80568](https://github.com/kubernetes/kubernetes/pull/80568), [@pohly](https://github.com/pohly))