Add documentation about private mount propagation (#8106)

* Trivial change to open release branch

* Undo trivial change

* Add documentation about private mount propagation
This commit is contained in:
Jan Šafránek 2018-04-26 21:23:26 +02:00 committed by k8s-ci-robot
parent c7ab858d7e
commit d623f631fd
1 changed files with 14 additions and 6 deletions

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@ -1076,16 +1076,24 @@ More details can be found [here](https://github.com/kubernetes/community/blob/ma
Mount propagation allows for sharing volumes mounted by a Container to
other Containers in the same Pod, or even to other Pods on the same node.
If the "`MountPropagation`" feature is disabled, volume mounts in pods are not propagated.
That is, Containers run with `private` mount propagation as described in the
[Linux kernel documentation](https://www.kernel.org/doc/Documentation/filesystems/sharedsubtree.txt).
If the "`MountPropagation`" feature is disabled or a Pod does not explicitly
specify specific mount propagation, volume mounts in the Pod's Containers are
not propagated. That is, Containers run with `private` mount propagation as
described in the [Linux kernel documentation](https://www.kernel.org/doc/Documentation/filesystems/sharedsubtree.txt).
Mount propagation of a volume is controlled by `mountPropagation` field in Container.volumeMounts.
Its values are:
* `None` - This volume mount will not receive any subsequent mounts
that are mounted to this volume or any of its subdirectories by the host.
In similar fashion, no mounts created by the Container will be visible on
the host. This is the default mode.
This mode is equal to `private` mount propagation as described in the
[Linux kernel documentation](https://www.kernel.org/doc/Documentation/filesystems/sharedsubtree.txt)
* `HostToContainer` - This volume mount will receive all subsequent mounts
that are mounted to this volume or any of its subdirectories. This is
the default mode.
that are mounted to this volume or any of its subdirectories.
In other words, if the host mounts anything inside the volume mount, the
Container will see it mounted there.
@ -1101,7 +1109,7 @@ Its values are:
In addition, all volume mounts created by the Container will be propagated
back to the host and to all Containers of all Pods that use the same volume.
A typical use case for this mode is a Pod with a `FlexVolume` driver or
A typical use case for this mode is a Pod with a `FlexVolume` or `CSI` driver or
a Pod that needs to mount something on the host using a `hostPath` volume.
This mode is equal to `rshared` mount propagation as described in the