@@ -43,34 +43,49 @@ scripts that launch kube-controller-manager.
...
@@ -43,34 +43,49 @@ scripts that launch kube-controller-manager.
### Admin Configuration
### Admin Configuration
No configuration is required by the admin! 3 cloud providers will be provided in the alpha version
The admin must define `StorageClass` objects that describe named "classes" of storage offered in a cluster. Different classes might map to arbitrary levels or policies determined by the admin. When configuring a `StorageClass` object for persistent volume provisioning, the admin will need to describe the type of provisioner to use and the parameters that will be used by the provisioner when it provisions a `PersistentVolume` belonging to the class.
of this feature: EBS, GCE, and Cinder.
The name of a StorageClass object is significant, and is how users can request a particular class, by specifying the name in their `PersistentVolumeClaim`. The `provisioner` field must be specified as it determines what volume plugin is used for provisioning PVs. 2 cloud providers will be provided in the beta version of this feature: EBS and GCE. The `parameters` field contains the parameters that describe volumes belonging to the storage class. Different parameters may be accepted depending on the `provisioner`. For example, the value `io1`, for the parameter `type`, and the parameter `iopsPerGB` are specific to EBS . When a parameter is omitted, some default is used.
When Kubernetes is running in one of those clouds, there will be an implied provisioner.
There is no provisioner when running outside of any of those 3 cloud providers.
#### AWS
A fourth provisioner is included for testing and development only. It creates HostPath volumes,
```yaml
which will never work outside of a single node cluster. It is not supported in any way except for
kind:StorageClass
local for testing and development. This provisioner may be used by passing
apiVersion:extensions/v1beta1
`--enable-hostpath-provisioner=true` to the controller manager while bringing it up.
metadata:
When using the `hack/local_up_cluster.sh` script, this flag is turned off by default.
name:slow
It may be turned on by setting the environment variable `ENABLE_HOSTPATH_PROVISIONER`
*`type`: `io1`, `gp2`, `sc1`, `st1`. See AWS docs for details. Default: `gp2`.
*`zone`: AWS zone. If not specified, a random zone in the same region as controller-manager will be chosen.
*`iopsPerGB`: only for `io1` volumes. I/O operations per second per GiB. AWS volume plugin multiplies this with size of requested volume to compute IOPS of the volume and caps it at 20 000 IOPS (maximum supported by AWS, see AWS docs).
#### GCE
```yaml
kind:StorageClass
apiVersion:extensions/v1beta1
metadata:
name:slow
provisioner:kubernetes.io/gce-pd
parameters:
type:pd-standard
zone:us-central1-a
```
```
*`type`: `pd-standard` or `pd-ssd`. Default: `pd-ssd`
*`zone`: GCE zone. If not specified, a random zone in the same region as controller-manager will be chosen.
### User provisioning requests
### User provisioning requests
Users request dynamically provisioned storage by including a storage class in their `PersistentVolumeClaim`.
Users request dynamically provisioned storage by including a storage class in their `PersistentVolumeClaim`.
The annotation `volume.alpha.kubernetes.io/storage-class` is used to access this experimental feature.
The annotation `volume.beta.kubernetes.io/storage-class` is used to access this experimental feature. It is required that this value matches the name of a `StorageClass` configured by the administrator.
In the future, admins will be able to define many storage classes.
In the future, the storage class may remain in an annotation or become a field on the claim itself.
The storage class may remain in an annotation or become a field on the claim itself.
> The value of the storage-class annotation does not matter in the alpha version of this feature. There is
a single implied provisioner per cloud (which creates 1 kind of volume in the provider). The full version of the feature
will require that this value matches what is configured by the administrator.
```
```
{
{
...
@@ -79,7 +94,7 @@ will require that this value matches what is configured by the administrator.
...
@@ -79,7 +94,7 @@ will require that this value matches what is configured by the administrator.
"metadata": {
"metadata": {
"name": "claim1",
"name": "claim1",
"annotations": {
"annotations": {
"volume.alpha.kubernetes.io/storage-class": "foo"
"volume.beta.kubernetes.io/storage-class": "slow"
}
}
},
},
"spec": {
"spec": {
...
@@ -97,26 +112,28 @@ will require that this value matches what is configured by the administrator.
...
@@ -97,26 +112,28 @@ will require that this value matches what is configured by the administrator.
### Sample output
### Sample output
This example uses HostPath but any provisioner would follow the same flow.
This example uses GCE but any provisioner would follow the same flow.
First we note there are no Persistent Volumes in the cluster. After creating a claim, we see a new PV is created
First we note there are no Persistent Volumes in the cluster. After creating a storage class and a claim including that storage class, we see a new PV is created
and automatically bound to the claim requesting storage.
and automatically bound to the claim requesting storage.
