When you have a persistent volume in OpenShift configured with “Retain”, the volume will switch to “Released” after the claim has been deleted. But what now? How to manually recycle it? This post will give a brief overview on how to manually reclaim the volume.
Deleting the claim
Delete the persistent volume claim in OpenShift is simple, either using the Web UI or by executing:
$ oc delete pvc/my-claim
If you check, then you will see the persistent volume is “Released” but not “Available”:
$ oc get pv NAME CAPACITY ACCESSMODES RECLAIMPOLICY STATUS CLAIM REASON AGE my-pv 40Gi RWO Retain Released my-project/my-claim 2d
What the documentation tells us
The OpenShift documentation states:
By default, persistent volumes are set to Retain. NFS volumes which are set to Recycle are scrubbed (i.e., rm -rf is run on the volume) after being released from their claim (i.e, after the user’s PersistentVolumeClaim bound to the volume is deleted). Once recycled, the NFS volume can be bound to a new claim.
At a different location it simply says:
Retained reclaim policy allows manual reclamation of the resource for those volume plug-ins that support it.
But how to actually do that? How to manually reclaim the volume?
Reclaiming the volume
First of all ensure that the data is actually deleted. Using NFS you will need to manually delete the content of the share using e.g. rm -Rf /exports/my-volume/*, but the be sure to the keep the actual export directory in place.
Now it is time to actually make the PV available again for being claimed. For this the reference to the previous claim (spec/claimRef) has to be removed from the persistent volume. You can manually do this from the Web UI or with short command from the shell (assuming you are using bash):
$ oc patch pv/my-pv --type json -p $'- op: remove\n path: /spec/claimRef' "my-pv" patched
This should return the volume into state “Available”:
$ oc get pv NAME CAPACITY ACCESSMODES RECLAIMPOLICY STATUS CLAIM REASON AGE my-pv 40Gi RWO Retain Available my-project/my-claim 2d