MountPropagation feature is now beta. As a consequence, all volume mounts in containers are now `rslave` on Linux by default. To make this default work in all Linux environments the entire mount tree should be marked as shareable, e.g. via `mount --make-rshared /`. All Linux distributions that use systemd already have the root directory mounted as rshared and hence they need not do anything. In Linux environments without systemd we recommend running `mount --make-rshared /` during boot before docker is started,...

    *   Dynamic provisioning is not supported with this feature yet.
*   [alpha] Containerized mount utilities
    *   Allow mount utilities, used to mount volumes, to run inside a container instead of on the host.
*   Bug Fixes

#### Storage

* [stable] Mount options

  * The ability to specify mount options for volumes is moved from beta to stable.

  * A new `MountOptions` field in the `PersistentVolume` spec is available to specify mount options. This field replaces an annotation.

  * A new `MountOptions` field in the `StorageClass` spec allows configuration of mount options for dynamically provisioned volumes.

* Fixes spurious 0-length API responses. ([#72856](https://github.com/kubernetes/kubernetes/pull/72856), [@liggitt](https://github.com/liggitt))

- AzureFile and CephFS use the new Mount library that prevents logging of sensitive mount options. ([#88684](https://github.com/kubernetes/kubernetes/pull/88684), [@saad-ali](https://github.com/saad-ali)) [SIG Storage]

* Because some plugins mount volume on sub-directory of volume path, we need to distinguish between volume path and mount path to fix issue in reconstruction. ([#74653](https://github.com/kubernetes/kubernetes/pull/74653), [@cofyc](https://github.com/cofyc))

- Fixed scanning of failed iSCSI targets. ([#74306](https://github.com/kubernetes/kubernetes/pull/74306), [@jsafrane](https://github.com/jsafrane))
- StorageOS volume plugin updated to fix an issue where volume mount succeeds even if request to mount via StorageOS API fails. ([#69782](https://github.com/kubernetes/kubernetes/pull/69782), [@darkowlzz](https://github.com/darkowlzz))

* Get parent dir via canonical absolute path when trying to judge mount-point ([#58433](https://github.com/kubernetes/kubernetes/pull/58433), [@yue9944882](https://github.com/yue9944882))

### Non-recursive Volume Ownership (FSGroup) graduates to Beta

By default, the `fsgroup` setting, if specified, recursively updates permissions for every file in a volume on every mount. This can make mount, and pod startup, very slow if the volume has many files. 

implementation is changed to not return an error when the specified target can be detected as not a mount point. On Linux, the behavior of detecting a mount point depends on `umount` command is validated when the mounter is created. Additionally, mount point checks will be skipped in CleanupMountPoint/CleanupMountWithForce if the mounter's Unmount having the changed behavior of not returning error when target is not a mount point. ([#109676](https://github.com/kubernetes/kubernetes/pull/109676), [@cartermckin...