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Moving CSI to Out of Tree section; linking to out of tree plugin FAQ (#7564)

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Cheng Xing
2018-03-03 11:46:54 -08:00
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commit c97a625547
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docs/concepts/storage/volumes.md
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@@ -215,38 +215,6 @@ keyed with `log_level`.
receive ConfigMap updates.
{: .note}
### csi
CSI stands for [Container Storage Interface](https://github.com/container-storage-interface/spec/blob/master/spec.md),
a specification attempting to establish an industry standard interface that
Container Orchestration Systems (COs) can use to expose arbitrary storage systems
to their container workloads.
For more information about the details, please check the
[design proposal](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/storage/container-storage-interface.md).
<!-- TODO: add link to the kubernetes extension section -->
The `csi` volume type is an in-tree CSI volume plugin for Pods to interact
with external CSI volume drivers running on the same node.
After having deployed a CSI compatible volume driver, users can use `csi` as the
volume type to mount the storage provided by the driver.
CSI persistent volume support is introduced in Kubernetes v1.9 as an alpha feature
which has to be explicitly enabled by the cluster administrator. In other words,
the cluster administrator needs to add "`CSIPersistentVolume=true`" to the
"`--feature-gates=`" flag for the apiserver, the controller-manager and the kubelet
components.
A CSI persistent volume has the following fields for users to specify:
- `driver`: A string value that specifies the name of the volume driver to use.
It has to be less than 63 characters and starts with a character. The driver
name can have '`.`', '`-`', '`_`' or digits in it.
- `volumeHandle`: A string value that uniquely identify the volume name returned
from the CSI volume plugin's `CreateVolume` call. The volume handle is then
used in all subsequent calls to the volume driver for referencing the volume.
- `readOnly`: An optional boolean value indicating whether the volume is to be
published as read only. Default is false.
### downwardAPI
A `downwardAPI` volume is used to make downward API data available to applications.
@@ -990,16 +958,50 @@ several media types.
## Out-of-Tree Volume Plugins
In addition to the previously listed volume types, storage vendors may create
custom plugins without adding it to the Kubernetes repository. This can be
achieved by using the `FlexVolume` plugin.
achieved by using either the `CSI` plugin or the `FlexVolume` plugin.
For storage vendors looking to create an out-of-tree volume plugin, [please refer to this FAQ](https://github.com/kubernetes/community/blob/master/sig-storage/volume-plugin-faq.md) for choosing between the plugin options.
### CSI
CSI stands for [Container Storage Interface](https://github.com/container-storage-interface/spec/blob/master/spec.md),
a specification attempting to establish an industry standard interface that
container orchestration systems can use to expose arbitrary storage systems
to their container workloads.
Please read
[CSI design proposal](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/storage/container-storage-interface.md) for further information.
<!-- TODO: add link to the kubernetes extension section -->
The `csi` volume type is an in-tree CSI volume plugin for Pods to interact
with external CSI volume drivers running on the same node.
After having deployed a CSI compatible volume driver, users can use `csi` as the
volume type to mount the storage provided by the driver.
CSI persistent volume support is an alpha feature in Kubernetes v1.9 and requires a
cluster administrator to enable it. To enable CSI persistent volume support, the
cluster administrator adds `CSIPersistentVolume=true` to the `--feature-gates` flag
for apiserver, controller-manager, and kubelet.
The following fields are available to storage administrators to configure a CSI
persistent volume:
- `driver`: A string value that specifies the name of the volume driver to use.
It has to be less than 63 characters and starts with a character. The driver
name can have '`.`', '`-`', '`_`' or digits in it.
- `volumeHandle`: A string value that uniquely identify the volume name returned
from the CSI volume plugin's `CreateVolume` call. The volume handle is then
used in all subsequent calls to the volume driver for referencing the volume.
- `readOnly`: An optional boolean value indicating whether the volume is to be
published as read only. Default is false.
### FlexVolume
`FlexVolume` enables users to mount vendor volumes into a pod. The vendor plugin
is implemented using a driver, an executable supporting a list of volume commands
defined by the `FlexVolume` API. Drivers must be installed in a pre-defined
volume plugin path on each node.
volume plugin path on each node. Pods interact with FlexVolume drivers through the `flexVolume` in-tree plugin.
More details can be found [here](https://github.com/kubernetes/community/blob/master/contributors/devel/flexvolume.md).
## Mount propagation
**Note:** Mount propagation is an alpha feature in Kubernetes 1.8 and may be