NFSv4 server - no uid/gid mapping

[Stephane Mutz]

Configuration:
NFS server: Ubuntu 12.10
NFS client: CentOS 5.8

Using NFSv4 to export directories.

After having updated my Ubuntu server to 12.10, CentOS 5.8 NFS client list all files directory as user / group nobody.

The setup was fully working in 12.04:
- idmapd.conf is fully configured on both client and server
- rpc.idmapd is running on both side
- uid/gid are identical on both side (using LDAP)
- LDAP authentication is working properly

Analyze logs on the client and network packets, the server is sending uid/gid (numbers) when answering GETATTR request while the client is expecting user@domain strings (which is what another Ubuntu 12.04 server is sending), Increasing verbosity of rpc.idmapd on the server didn't yield anything in the server logs. It seems that the uid to name translation is not happening.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: nfs-kernel-server 1:1.2.6-3ubuntu2
ProcVersionSignature: Ubuntu 3.5.0-21.32-generic 3.5.7.1
Uname: Linux 3.5.0-21-generic x86_64
ApportVersion: 2.6.1-0ubuntu9
Architecture: amd64
Date: Tue Jan 8 13:00:22 2013
InstallationDate: Installed on 2011-05-31 (587 days ago)
InstallationMedia: Ubuntu-Server 11.04 "Natty Narwhal" - Release amd64 (20110426)
MarkForUpload: True
ProcEnviron:
 SHELL=/bin/bash
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 LANGUAGE=en_US:en
SourcePackage: nfs-utils
UpgradeStatus: Upgraded to quantal on 2013-01-04 (3 days ago)

[Craig Yoshioka (craigyk)]

I can confirm seeing this as well. Furthermore, I've narrowed it down by trying multiple linux distros (ubuntu 12.04 and 13.04, mint 15, debian, centos) and different ldap systems (ldap, ldapd, sssd).

The strangest instance is that ubuntu 12.04 desktop is broken but 12.04 server works. If I upgrade a 12.04 server by installing the desktop package, it continues working (but not if I install 12.04 desktop directly from CD).

To be clear. In all the configurations I've tested I can get ldap and nss/pam working correctly (getent shows all the correct entries and I can su and login as ldap users) but on some machines, Ubuntu 12.04 Desktop and Ubuntu 13.04 Desktop AND Server NFS4 idmap is broken with ldap users. Sometimes the correct user and groups show up on the files, but trying to chown and chmod the files fails. THe system log also fills up with errors of the type the OP described, where idmap is tyring to map a userid number as a string rather than username@domain.