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Raw block volume GA (#19338)

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* Raw block volume GA

Feature BlockVolume reaches GA in 1.17

* Add volumeMode overview
This commit is contained in:
Jan Šafránek
2020-03-16 12:10:35 +01:00
committed by GitHub
parent 25a084a6e4
commit 94fbc12a6b
3 changed files with 32 additions and 27 deletions
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content/en/docs/concepts/storage/persistent-volumes.md
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@@ -319,12 +319,24 @@ Currently, storage size is the only resource that can be set or requested. Futu
### Volume Mode
{{< feature-state for_k8s_version="v1.13" state="beta" >}}
{{< feature-state for_k8s_version="v1.18" state="stable" >}}
Prior to Kubernetes 1.9, all volume plugins created a filesystem on the persistent volume.
Now, you can set the value of `volumeMode` to `block` to use a raw block device, or `filesystem`
to use a filesystem. `filesystem` is the default if the value is omitted. This is an optional API
parameter.
Kubernetes supports two `volumeModes` of PersistentVolumes: `Filesystem` and `Block`.
`volumeMode` is an optional API parameter.
`Filesystem` is the default mode used when `volumeMode` parameter is omitted.
A volume with `volumeMode: Filesystem` is *mounted* into Pods into a directory. If the volume
is backed by a block device and the device is empty, Kuberneretes creates a filesystem
on the device before mounting it for the first time.
You can set the value of `volumeMode` to `Block` to use a volume as a raw block device.
Such volume is presented into a Pod as a block device, without any filesystem on it.
This mode is useful to provide a Pod the fastest possible way to access a volume, without
any filesystem layer between the Pod and the volume. On the other hand, the application
running in the Pod must know how to handle a raw block device.
See [Raw Block Volume Support](docs/concepts/storage/persistent-volumes/#raw-block-volume-support)
for an example on how to use a volume with `volumeMode: Block` in a Pod.
### Access Modes
@@ -559,24 +571,21 @@ spec:
## Raw Block Volume Support
{{< feature-state for_k8s_version="v1.13" state="beta" >}}
{{< feature-state for_k8s_version="v1.18" state="stable" >}}
The following volume plugins support raw block volumes, including dynamic provisioning where
applicable:
* AWSElasticBlockStore
* AzureDisk
* CSI
* FC (Fibre Channel)
* GCEPersistentDisk
* iSCSI
* Local volume
* OpenStack Cinder
* RBD (Ceph Block Device)
* VsphereVolume (alpha)
{{< note >}}
Only FC and iSCSI volumes supported raw block volumes in Kubernetes 1.9.
Support for the additional plugins was added in 1.10.
{{< /note >}}
* VsphereVolume
### Persistent Volumes using a Raw Block Volume