Chapter 5. Expanding persistent volumes Learn how to expand persistent volumes in MicroShift. 5.1. Expanding CSI volumes 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 Prerequisites 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." Procedure 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. Red Hat build of MicroShift adds the Resizing condition to the PVC during expansion, which is removed after expansion completes. 5.2. Expanding local volumes You can manually expand persistent volumes (PVs) and persistent volume claims (PVCs) created by using the local storage operator (LSO). Procedure 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. 5.3. Expanding persistent volume claims (PVCs) with a file system Expanding PVCs based on volume types that need file system resizing, such as GCE Persistent Disk volumes (gcePD), AWS Elastic Block Store EBS (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. Prerequisites The controlling StorageClass object must have allowVolumeExpansion set to true . Procedure 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: USD 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. 5.4. Recovering from failure when expanding volumes If expanding underlying storage fails, the Red Hat build of MicroShift 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. Procedure 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.

Commands:
kind: PersistentVolumeClaim apiVersion: v1 metadata: name: ebs spec: storageClass: "storageClassWithFlagSet" accessModes: - ReadWriteOnce resources: requests: storage: 8Gi 1
oc describe pvc <pvc_name>