Chapter 6. Expanding persistent volumes

Procedure

1. For the persistent volume claim (PVC), set .spec.resources.requests.storage to the desired new size.
2. Watch the status.conditions field of the PVC to see if the resize has completed. Red Hat build of MicroShift adds the Resizing condition to the PVC during expansion, which is removed after expansion completes.

Procedure

1. Expand the underlying devices. Ensure that appropriate capacity is available on these devices.
2. Update the corresponding PV objects to match the new device sizes by editing the .spec.capacity field of the PV.
3. For the storage class that is used for binding the PVC to PV, set the allowVolumeExpansion field to true.

4. For the PVC, set the .spec.resources.requests.storage field to match the new size.

   Kubelet automatically expands the underlying file system on the volume, if necessary, and updates the status field of the PVC to reflect the new size.

Procedure

1. 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

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   • requests.storage: Specifies the size for the PVC.

2. 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>

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3. 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 re-create a 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.

Procedure

1. Mark the persistent volume (PV) that is bound to the PVC with the Retain reclaim policy. Change the persistentVolumeReclaimPolicy field to Retain.
2. Delete the PVC.
3. 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.
4. Re-create the PVC in a smaller size, or a size that can be allocated by the underlying storage provider.
5. Restore the reclaim policy on the PV.