The problem

When using nfs4 and a freshly installed Linux system it can happen that you run in the situation that all files and directories have no owner and group:

drwxr-xr-x 4 nobody nogroup 4096 Okt 26 17:10 tmp
-rw-r--r-- 1 nobody nogroup 83 Okt 23 00:50 todo
-rw-r--r-- 1 nobody nogroup 97 Okt 23 00:09 todo~

This is because NFS4 needs the id mapping demon idmapd and also a correct config for it.

The solution

Change in /etc/default/nfs-common the line

NEED_IDMAPD=

to

NEED_IDMAPD=yes

and also in /etc/idmapd.conf the parameter Domain to a domain name that needs to be the same in all idmapd.conf configs you’re actually using:

Domain = localdomain

That’s it, restart nfsd and it should work.