* --google-json-key
    * --log_cadvisor_usage
    * --machine_id_file
    * --storage_driver_user
    * --storage_driver_password
    * --storage_driver_host
    * --storage_driver_db
    * --storage_driver_table
    * --storage_driver_secure
    * --storage_driver_buffer_duration

([#57613](https://github.com/kubernetes/kubernetes/pull/57613), [@mtaufen](https://github.com/mtaufen))

  as it requires installation of AzureFile CSI Driver. Users should enable CSIMigration and
  CSIMigrationAzureFile features and install the [AzureFile CSI Driver](https://github.com/kubernetes-sigs/azurefile-csi-driver)
  to avoid disruption to existing Pod and PVC objects at that time. Azure File CSI driver does not support using same persistent

- Unlocked the `CSIMigrationvSphere` feature gate.
  The change allow users to continue using the in-tree vSphere driver,pending a vSphere
  CSI driver release that has with GA support for Windows, XFS, and raw block access. ([#116342](https://github.com/kubernetes/kubernetes/pull/116342), [@msau42](https://github.com/msau42)) [SIG Storage]

* Fix a scalability issue where high rates of event writes degraded etcd performance. ([#64539](https://github.com/kubernetes/kubernetes/pull/64539), [@ccding](https://github.com/ccding))

## Known Issues

- Promote CSIMigrationOpenStack to Beta (off by default since it requires installation of the OpenStack Cinder CSI Driver. The in-tree AWS OpenStack Cinder driver "kubernetes.io/cinder" was deprecated in 1.16 and will be removed in 1.20. Users should enable CSIMigration + CSIMigrationOpenStack features and install the OpenStack Cinder CSI Driver (https://github.com/kubernetes/cloud-provider-openstack) to avoid disruption to existing Pod and PVC objects at that time. Users should...

 - Deprecated support for CSI migration of `Ceph RBD volumes`. Users who were relying on Kubernetes' ability

* [alpha] Improve Flex volume deployment

  * Flex volume driver deployment is simplified in the following ways:

    * New driver files can now be automatically discovered and initialized without requiring a kubelet or controller-manager restart.

    * A sample DaemonSet to deploy Flexvolume drivers is now available.

    * 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

- Unlocked the `CSIMigrationvSphere` feature gate. The change allow users to continue using the in-tree vSphere driver,pending a vSphere CSI driver release that has with GA support for Windows, XFS, and raw block access. ([#116396](https://github.com/kubernetes/kubernetes/pull/116396), [@msau42](https://github.com/msau42)) [SIG Storage]

### Bug or Regression