I have boxes where nfs-server does not start, because a failed
dependency:

Jul 31 00:00:32 lugh mount[249]: mount: sunrpc already mounted or /var/lib/nfs/rpc_pipefs busy
Jul 31 00:00:32 lugh mount[249]: mount: according to mtab, sunrpc is already mounted on /var/lib/nfs/rpc_pipefs
Jul 31 00:00:32 lugh mount[248]: mount: unknown filesystem type 'nfsd'
Jul 31 00:00:32 lugh systemd[1]: proc-fs-nfsd.mount mount process exited, code=exited status=32
Jul 31 00:00:32 lugh systemd[1]: Job nfs-rquotad.service/start failed with result 'dependency'.

...and all the nfs server chain fails.

This is because pipefs is mounted on module insertion on 00_modprobe.conf.
The solution is to kill the 'install' lines for nfsd,sunrcp.

Also, the alias 'alias nfs4 nfs' is duplicated in nfs.conf, and probably some
others should be moved to nfs.conf, like rpc_pipefs, rpc_svc_gss_pipefs...

More deatiled bug description here:

https://bugzilla.redhat.com/show_bug.cgi?id=744463