Use service IP instead of internal dns

[duebbert]

Thank you so much for documenting all this! It helped to finally set up an NFS server after all other instructions failed.

One point that I noticed: you're using the internal dns name for the PV. This kind of negates the whole point of setting up a service for the NFS server. The whole setup works fine if you use the ClusterIP of the service but obviously the PV yaml needs editing then.