* 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).

  * 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

* GCI/Trusty: Support ABAC authorization ([#24950](https://github.com/kubernetes/kubernetes/pull/24950), [@andyzheng0831](https://github.com/andyzheng0831))
* 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))

  previous releases. When this happens, a `LifecycleHTTPFallback` event is recorded
  in the namespace of the pod and a `kubelet_lifecycle_handler_http_fallbacks_total`
  metric in the kubelet is incremented. Cluster administrators can opt out of the
  expanded lifecycle handler capabilities by setting
  `--feature-gates=ConsistentHTTPGetHandlers=false` in `kubelet`.'