// +optional
  optional NFSVolumeSource nfs = 5;

  // rbd represents a Rados Block Device mount on the host that shares a pod's lifetime.
  // More info: https://examples.k8s.io/volumes/rbd/README.md
  // +optional
  optional RBDPersistentVolumeSource rbd = 6;

  // iscsi represents an ISCSI Disk resource that is attached to a

* K8s now supports rbd-nbd for Ceph rbd volume mounts. ([#58916](https://github.com/kubernetes/kubernetes/pull/58916), [@ianchakeres](https://github.com/ianchakeres))

- CephRBD volume plugin ( `kubernetes.io/rbd`) was removed in this release. And its csi migration support was also removed, so the `rbd` volume type became non-functional. Alternative is to use RBD CSI driver (https://github.com/ceph/ceph-csi/) in your Kubernetes Cluster. A re-deployment of your application is required to use the new driver if you were using `kubernetes.io/rbd` volume plugin before upgrading cluster version to 1.31+. ([#124546](https://git...

- This release enables in-tree RBD migration to CSI driver with a couple of feature gates.  These featuregates are alpha in this release.

  - `CSIMigrationRBD`: when enabled, it will redirect traffic from in tree rbd plugin ( kubernetes.io/rbd )  to CSI driver ( rbd.csi.ceph.com) , default to `false` now.
  - `IntreePluginRBDUnregister`: Disables the RBD in-tree driver

  The feature gates can be enabled by:

 - Deprecated support for CSI migration of `Ceph RBD volumes`. Users who were relying on Kubernetes' ability
  to migrate to an out-of-tree storage driver should complete that migration before the support for it is removed. ([#118303](https://github.com/kubernetes/kubernetes/pull/118303), [@carlory](https://github.com/carlory))
 - RBD volume plugin (`kubernetes.io/rbd`) has been deprecated in this release

    - [kube-proxy](#kube-proxy)
    - [Scheduler](#scheduler)
    - [Volume Plugins](#volume-plugins)
      - [Azure Disk](#azure-disk)
      - [GlusterFS](#glusterfs)
      - [Photon](#photon)
      - [rbd](#rbd)
      - [vSphere](#vsphere-1)
      - [Other Notable Changes](#other-notable-changes-15)
  - [Changes to Cluster Provisioning Scripts](#changes-to-cluster-provisioning-scripts)
    - [AWS](#aws-1)
    - [Juju](#juju)

          * 'node.kubernetes.io/memory-pressure=:NoSchedule' if MemoryPressure is true
          * 'node.kubernetes.io/out-of-disk=:NoSchedule' if OutOfDisk is true
* rbd: default image format to v2 instead of deprecated v1 ([#51574](https://github.com/kubernetes/kubernetes/pull/51574), [@dillaman](https://github.com/dillaman))

    *   Only Fibre Channel volume plugin supports exposes this functionality, in this release.
*   [alpha] Volume resizing
    *   Added file system resizing for the following volume plugins: GCE PD, Ceph RBD, AWS EBS, OpenStack Cinder
*   [alpha] Topology Aware Volume Scheduling

### SIG Storage

* AWS EBS, Azure Disk, GCE PD and Ceph RBD volume plugins now support dynamic provisioning of raw block volumes. ([#64447](https://github.com/kubernetes/kubernetes/pull/64447), [@jsafrane](https://github.com/jsafrane))

* Use gcr.io as a Docker registry mirror when setting up a cluster in GCE. ([#25841](https://github.com/kubernetes/kubernetes/pull/25841), [@ojarjur](https://github.com/ojarjur))
* correction on rbd volume object and defaults ([#25490](https://github.com/kubernetes/kubernetes/pull/25490), [@rootfs](https://github.com/rootfs))