- 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....

* fixes a bug around using the Global config ElbSecurityGroup where Kuberentes would modify the passed in Security Group. ([#49805](https://github.com/kubernetes/kubernetes/pull/49805), [@nbutton23](https://github.com/nbutton23))
* Updates Cinder AttachDisk operation to be more reliable by delegating Detaches to volume manager. ([#50042](https://github.com/kubernetes/kubernetes/pull/50042), [@jingxu97](https://github.com/jingxu97))

 - OpenStack Cinder CSI migration is on by default, Clinder CSI driver must be installed on clusters on OpenStack for Cinder volumes to work. ([#98538](https://github.com/kubernetes/kubernetes/pull/98538), [@dims](https://github.com/dims)) [SIG Storage]

- Added Custom Resource support to `kubectl autoscale` ([#72678](https://github.com/kubernetes/kubernetes/pull/72678), [@rmohr](https://github.com/rmohr))
- Cinder volume limit can now be configured from node too ([#74542](https://github.com/kubernetes/kubernetes/pull/74542), [@gnufied](https://github.com/gnufied))

* Make volume usage metrics available for Cinder ([#62668](https://github.com/kubernetes/kubernetes/pull/62668), [@zetaab](https://github.com/zetaab))

### **OpenStack**

*   OpenStack Cinder support has been improved:
    *   Cinder version detection now works properly. ([#53115](https://github.com/kubernetes/kubernetes/pull/53115),[ @FengyunPan](https://github.com/FengyunPan))

  * Dynamic Provisioning of PersistentVolumes: Kubernetes previously required all
volumes to be manually provisioned by a cluster administrator before use. With
this feature, volume plugins that support it (GCE PD, AWS EBS, and Cinder) can
automatically provision a PersistentVolume to bind to an unfulfilled
PersistentVolumeClaim.
  * Run multiple schedulers in parallel, e.g. one or more custom schedulers

  when the corresponding csi driver was installed:
  - `awsElasticBlockStore` for `ebs.csi.aws.com`
  - `azureDisk` for `disk.csi.azure.com`
  - `gcePersistentDisk` for `pd.csi.storage.googleapis.com`
  - `cinder` for `cinder.csi.openstack.org`
  - `csi`
  However it was still enforced using a limit in CSINode objects. ([#126924](https://github.com/kubernetes/kubernetes/pull/126924), [@carlory](https://github.com/carlory))

* fix cinder volume dir umount issue [#24717](https://github.com/kubernetes/kubernetes/pull/24717) ([#24718](https://github.com/kubernetes/kubernetes/pull/24718), [@chengyli](https://github.com/chengyli))

conjunction with SIG Cloud Provider, is focusing on moving internal APIs that the OpenStack (and other providers) depends upon to staging to guarantee API stability. This work also included abstracting the in-tree Cinder API and refactoring code to the external Cinder provider to remove additional Cinder volume provider code.

Additional work was also done to implement an OpenStack driver for the Cluster API effort lead by SIG Cluster Lifecycle. For the external Cloud-Provider-OpenStack code, the...