## Known Issues

 - Kubeadm: remove the automatic detection and matching of cgroup drivers for Docker. For new clusters if you have not configured the cgroup driver explicitly you might get a failure in the `kubelet` on driver mismatch (kubeadm clusters should be using the `systemd` driver). Also remove the `IsDockerSystemdCheck` preflight check (warning) that checks if the Docker cgroup driver is set to `systemd`. Ideally such detection / coordination should be on the side of CRI implementers...

- The alpha Dynamic Resource Allocation gRPC API is still available, but might be removed in future releases. Driver authors should update their DRA drivers to use the v1beta1 gRPC API. ([#128646](https://github.com/kubernetes/kubernetes/pull/128646), [@pohly](https://github.com/pohly)) [SIG Node and Testing]

### Security Improvements for CSI Drivers (Alpha)

### Failing Test

- DRA driver helper: Fixed handling of apiserver restart when running on a Kubernetes version which did not support the `resource.k8s.io` version used by the DRA driver. ([#133076](https://github.com/kubernetes/kubernetes/pull/133076), [@pohly](https://github.com/pohly)) [SIG Node and Testing]

- kubelet + DRA: For DRA driver plugins (and only for those!), the kubelet now supports a rolling update with `maxSurge > 0` in the driver's DaemonSet. A DRA driver must support this, which can be done via the k8s.io/dynamic-resource-allocation/kubeletplugin helper package. ([#129832](https://github.com/kubernetes/kubernetes/pull/129832), [@po...

### 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))

- 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...

  by default. The CSI drivers can make use of the `secretRef` values passed in `NodeExpansion`
  request optionally sent by the CSI Client from this release onwards. ([#121303](https://github.com/kubernetes/kubernetes/pull/121303), [@humblec](https://github.com/humblec))

### Deprecation of FlexVolume

FlexVolume is deprecated. Out-of-tree CSI driver is the recommended way to write volume drivers in Kubernetes.
See [this doc](https://github.com/kubernetes/community/blob/master/sig-storage/volume-plugin-faq.md#kubernetes-volume-plugin-faq-for-storage-vendors) for more information.
Maintainers of FlexVolume drivers should implement a CSI driver and move users of FlexVolume to CSI.