$ oc edit storageclass <storage_class_name> (1)
Before you can expand persistent volumes, the StorageClass
object must
have the allowVolumeExpansion
field set to true
.
Edit the StorageClass
object and add the allowVolumeExpansion
attribute by running the following command:
$ oc edit storageclass <storage_class_name> (1)
1 | Specifies the name of the storage class. |
The following example demonstrates adding this line at the bottom of the storage class configuration.
apiVersion: storage.k8s.io/v1
kind: StorageClass
...
parameters:
type: gp2
reclaimPolicy: Delete
allowVolumeExpansion: true (1)
1 | Setting this attribute to true allows PVCs to be
expanded after creation. |
You can use the Container Storage Interface (CSI) to expand storage volumes after they have already been created.
CSI volume expansion does not support the following:
Recovering from failure when expanding volumes
Shrinking
The underlying CSI driver supports resize.
Dynamic provisioning is used.
The controlling StorageClass
object has allowVolumeExpansion
set to true
. For more information, see "Enabling volume expansion support."
For the persistent volume claim (PVC), set .spec.resources.requests.storage
to the desired new size.
Watch the status.conditions
field of the PVC to see if the resize has completed. OpenShift Container Platform adds the Resizing
condition to the PVC during expansion, which is removed after expansion completes.
When using FlexVolume to connect to your back-end storage system, you can expand persistent storage volumes after they have already been created. This is done by manually updating the persistent volume claim (PVC) in OpenShift Container Platform.
FlexVolume allows expansion if the driver is set with RequiresFSResize
to true
. The FlexVolume can be expanded on pod restart.
Similar to other volume types, FlexVolume volumes can also be expanded when in use by a pod.
The underlying volume driver supports resize.
The driver is set with the RequiresFSResize
capability to true
.
Dynamic provisioning is used.
The controlling StorageClass
object has allowVolumeExpansion
set to true
.
To use resizing in the FlexVolume plugin, you must implement the ExpandableVolumePlugin
interface using these methods:
RequiresFSResize
If true
, updates the capacity directly. If false
, calls the ExpandFS
method to finish the filesystem resize.
ExpandFS
If true
, calls ExpandFS
to resize filesystem after physical volume expansion is done. The volume driver can also perform physical volume resize together with filesystem resize.
Because OpenShift Container Platform does not support installation of FlexVolume plugins on control plane nodes, it does not support control-plane expansion of FlexVolume. |
You can manually expand persistent volumes (PVs) and persistent volume claims (PVCs) created by using the local storage operator (LSO).
Expand the underlying devices. Ensure that appropriate capacity is available on these devices.
Update the corresponding PV objects to match the new device sizes by editing the .spec.capacity
field of the PV.
For the storage class that is used for binding the PVC to PVet, set allowVolumeExpansion:true
.
For the PVC, set .spec.resources.requests.storage
to match the new size.
Kubelet should automatically expand the underlying file system on the volume, if necessary, and update the status field of the PVC to reflect the new size.
Expanding PVCs based on volume types that need file system resizing, such as GCE, EBS, and Cinder, is a two-step process. First, expand the volume objects in the cloud provider. Second, expand the file system on the node.
Expanding the file system on the node only happens when a new pod is started with the volume.
The controlling StorageClass
object must have allowVolumeExpansion
set to true
.
Edit the PVC and request a new size by editing spec.resources.requests
. For example, the following expands the ebs
PVC to 8 Gi:
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: ebs
spec:
storageClass: "storageClassWithFlagSet"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 8Gi (1)
1 | Updating spec.resources.requests to a larger amount expands the PVC. |
After the cloud provider object has finished resizing, the PVC is set to FileSystemResizePending
. Check the condition by entering the following command:
$ oc describe pvc <pvc_name>
When the cloud provider object has finished resizing, the PersistentVolume
object reflects the newly requested size in PersistentVolume.Spec.Capacity
. At this point, you can create or recreate a new pod from the PVC to finish the file system resizing. Once the pod is running, the newly requested size is available and the FileSystemResizePending
condition is removed from the PVC.
If expanding underlying storage fails, the OpenShift Container Platform administrator can manually recover the persistent volume claim (PVC) state and cancel the resize requests. Otherwise, the resize requests are continuously retried by the controller.
Mark the persistent volume (PV) that is bound to the PVC with the Retain
reclaim policy. This can be done by editing the PV and changing persistentVolumeReclaimPolicy
to Retain
.
Delete the PVC.
Manually edit the PV and delete the claimRef
entry from the PV specs to ensure that the newly created PVC can bind to the PV marked Retain
. This marks the PV as Available
.
Re-create the PVC in a smaller size, or a size that can be allocated by the underlying storage provider.
Set the volumeName
field of the PVC to the name of the PV. This binds the PVC to the provisioned PV only.
Restore the reclaim policy on the PV.
The controlling StorageClass
object has allowVolumeExpansion
set to true
(see Enabling volume expansion support).