NFS – User Mapping Configuration Guide

centoslinuxnfs

I have two machines, both with CentOS 6.4 installed, connected on the same private network.

One of them has the purpose of being a NFS server, and the other it's client.

On the server machine (server) I exported the directory /net/directory by adding the line to the /etc/exports file

/net/directory *(rw,sync,no_root_squash)

With the service started, I went to the client and add mount point to /etc/fstab

server:/net/directory   /client/directory       nfs defaults    0 0

And then mounted

# mount /client/directory

The problem is that when I create a new file/directory inside the mounted point from the client, that file is going be mapped as nobody:nobody when created as an unknown user of the server side.

Here's an example (for clarification)

On the client side only there is an user and group with the same name called testuser

  • username: testuser
  • UID: 1001
  • GID: 1001

On the client side I create a file as testuser

[testuser@client ~]# touch /client/directory/test

Then I list the directory content

[testuser@client ~]# ls -l /client/directory
total 0
-rw-r--r--. 1 nobody nobody 0 Jul  2 16:46 test

But on the server side everything is as expected:

[root@earth ~]# ls -l /net/directory
total 0
-rw-r--r--. 1 1001 1001 0 Jul  2 16:46 test

I want the same result on the client side:

– the file must be with UID:GID as 1001:1001

What am I doing wrong? Is this a server or client issue?

I searched around several NFS manuals, and nothing is helping me.

Does anyone knows how can I do this (without creating the user on the server side)?

Thank you.

Best Answer

Check that domain in /etc/idmapd.conf is the same on the client and server. Check that rpc.idmapd is running on the client and the server. And, of course, user should exist on the client and server. NFSv4 uses user principals on the wire and it's responsibility the client and server to provide a propper mapping. As you use AUTH_SYS local uid/gid propogated to the server on create, but 'ls' rquires mapping to work.

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