Comment 18 for bug 791588

I struggled with the undesired symptom that names are shown in ls -l output of an NFS filesystem as nobody, instead of the expected user name as known to the NFS server and client.

Background: I'm using 12.10 client to mount an NFS filesystem exported from a 12.04 server. I have the same users on both systems, altho with different numeric user IDs, listed in /etc/passwd. Both systems have proper /etc/hosts entries so that the command dnsdomainname returns the same string. On the client, /etc/default/nfs-common has a line "NEED_IDMAPD=yes". The filesystem mount requests are accepted.

This bug report suggested mounting the rpc-pipe filesystem manually. This was successful for me:

  $ sudo service idmapd stop
  $ sudo mount -t rpc_pipefs rpc_pipefs /run/rpc_pipefs
  $ sudo rpc.idmapd -v -f

And then the idmapd process stayed in the foreground, messages were logged to the window, and then I could debug the id<->name mapping.

When I first installed the nfs-common software on the client, I hit problems much like what is described in this bug report. Google lead me here :) For example syslog showed this entry:

Dec 27 09:58:20 earthquake rpc.idmapd[8446]: main: open(/run/rpc_pipefs/nfs): No such file or directory

Maybe I should have rebooted the machine after doing the apt-get, or some other service needed to be restarted, I just don't know. After a reboot, idmapd starts as I expect.

HTH