Manage Volumes

Prerequisites

• Working DirectPV plugin.

  To install the plugin, refer to the plugin installation guide.

• Added drives in DirectPV.

  Refer to the drive management guide.

Add volume

Refer to the volume provisioning guide.

List volume

To get information of volumes from DirectPV, run the list volumes command. The output resembles the following:

$ kubectl directpv list volumes
┌─────────────────────────────────────────┬──────────┬───────┬───────┬───────────┬──────────────┬─────────┐
│ VOLUME                                  │ CAPACITY │ NODE  │ DRIVE │ PODNAME   │ PODNAMESPACE │ STATUS  │
├─────────────────────────────────────────┼──────────┼───────┼───────┼───────────┼──────────────┼─────────┤
│ pvc-a1b2c3d4-e5f6-7890-abcd-ef123456    │ 10 GiB   │ node1 │ sdb   │ minio-0   │ default      │ Bounded │
│ pvc-b2c3d4e5-f6a7-8901-bcde-f1234567    │ 10 GiB   │ node1 │ sdc   │ minio-1   │ default      │ Bounded │
└─────────────────────────────────────────┴──────────┴───────┴───────┴───────────┴──────────────┴─────────┘

Expand volume

DirectPV supports online volume expansion without requiring a restart of the pods using those volumes. This is done automatically after expanding the size for the related Persistent Volume Claim (PVC).

1. Get the PVC YAML

   kubectl get pvc [PersistentVolumeClaimName] -o yaml > my-file-name.yaml

2. In the PVC, modify spec.resources.requests.storage to change the requested size.

3. Apply the updated PVC to the Kubernetes environment, such as with kubectl apply.

   After applying the change, the PVC updates and DirectPV automatically increases the size of the volume assigned to the claim.

4. Verify the change with kubectl get pvc [PersistentVolumeClaimName] -o yaml

   Review status.capacity.storage to see the updated size.

Delete volume

A volume can be deleted only if no pod is using the volume and it is in the Ready state. Run the kubectl delete pvc command to trigger DirectPV volume deletion. Deleting a volume results in permanent data loss. Be sure to confirm the volume you are deleting.

# Delete `sleep-pvc` volume
kubectl delete pvc sleep-pvc

Clean stale volumes

When Pods and/or Persistent Volume Claims are deleted forcefully, associated DirectPV volumes might be left undeleted. This leads to the volumes becoming stale. Remove stale volumes by running the clean command.

kubectl directpv clean --all

Suspend volumes

By Kubernetes design, a StatefulSet workload is active only if all of its pods are in running state. A faulty volume prevents the StatefulSet from starting up.

DirectPV provides a workaround to suspend failed volumes by mounting them on an empty /var/lib/directpv/tmp directory with read-only access. This can be done by executing the suspend volumes command.

kubectl directpv suspend volumes --nodes node-1 --drives dm-3 --dangerous

Suspended volumes can be resumed once they are fixed. Upon resuming, the corresponding volumes return to using the respective allocated drives.

This can be done by using the resume volumes command.

kubectl directpv resume volumes --nodes node-1 --drives dm-3