I recently upgraded my rancher RKE cluster to 1.20.4, and found that nfs-client-proisioner is broken. It failed to create new PVC with an "unexpected error getting claim reference: selfLink was empty, can't make reference" error.
After some google search I found this. However, there is no documentation on how to migrate from nfs-client-provisioner, even it seems to fixed the issue.
When asking around in #sig-storage, @thansen suggested to give democratic-csi a try, which has a crude yet simple implementation of nfs-client as a CSI driver.
Here's capture how I get it to work, after helps from @thansen
My setup: RKE cluster on k8s v1.20.4, 3x Fedora 33 node, managed by Rancher 2.5.6, NFS server on a Thecus N5550, nfs-client-provisioner used for dynamic PVC provisioning.