Setting Up An NFS Server And Client On Debian Etch

Version 1.0
Author: Falko Timme <ft [at] falkotimme [dot] com>
Last edited 11/29/2007

This guide explains how to set up an NFS server and an NFS client on Debian Etch. NFS stands for Network File System; through NFS, a client can access (read, write) a remote share on an NFS server as if it was on the local hard disk.

I do not issue any guarantee that this will work for you!

1 Preliminary Note

I'm using two Debian systems here:

• NFS Server: server.example.com, IP address: 192.168.0.100
• NFS Client: client.example.com, IP address: 192.168.0.101

2 Installing NFS

server:

On the NFS server we run:

apt-get install nfs-kernel-server nfs-common portmap

client:

On the client we can install NFS as follows:

apt-get install nfs-common portmap

3 Exporting Directories On The Server

server:

I'd like to make the directories /home and /var/nfs accessible to the client; therefore we must "export" them on the server.

When a client accesses an NFS share, this normally happens as the user nobody. Usually the /home directory isn't owned by nobody (and I don't recommend to change its ownership to nobody!), and because we want to read and write on /home, we tell NFS that accesses should be made as root (if our /home share was read-only, this wouldn't be necessary). The /var/nfs directory doesn't exist, so we can create it and change its ownership to nobody and nogroup:

mkdir /var/nfs
chown nobody:nogroup /var/nfs

Now we must modify /etc/exports where we "export" our NFS shares. We specify /home and /var/nfs as NFS shares and tell NFS to make accesses to /home as root (to learn more about /etc/exports, its format and available options, take a look at

man 5 exports

)

vi /etc/exports

# /etc/exports: the access control list for filesystems which may be exported
#               to NFS clients.  See exports(5).
#
# Example for NFSv2 and NFSv3:
# /srv/homes       hostname1(rw,sync) hostname2(ro,sync)
#
# Example for NFSv4:
# /srv/nfs4        gss/krb5i(rw,sync,fsid=0,crossmnt)
# /srv/nfs4/homes  gss/krb5i(rw,sync)
#
/home           192.168.0.101(rw,sync,no_root_squash)
/var/nfs        192.168.0.101(rw,sync)

(The no_root_squash option makes that /home will be accessed as root.)

Whenever we modify /etc/exports, we must run

exportfs -a

afterwards to make the changes effective.

4 Mounting The NFS Shares On The Client

client:

First we create the directories where we want to mount the NFS shares, e.g.:

mkdir -p /mnt/nfs/home
mkdir -p /mnt/nfs/var/nfs

Afterwards, we can mount them as follows:

mount 192.168.0.100:/home /mnt/nfs/home
mount 192.168.0.100:/var/nfs /mnt/nfs/var/nfs

You should now see the two NFS shares in the outputs of

df -h

client:~# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1              30G  748M   27G   3% /
tmpfs                  63M     0   63M   0% /lib/init/rw
udev                   10M   52K   10M   1% /dev
tmpfs                  63M     0   63M   0% /dev/shm
192.168.0.100:/home    30G  764M   27G   3% /mnt/nfs/home
192.168.0.100:/var/nfs
                       30G  764M   27G   3% /mnt/nfs/var/nfs
client:~#

and

mount

client:~# mount
/dev/sda1 on / type ext3 (rw,errors=remount-ro)
tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
udev on /dev type tmpfs (rw,mode=0755)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620)
192.168.0.100:/home on /mnt/nfs/home type nfs (rw,addr=192.168.0.100)
192.168.0.100:/var/nfs on /mnt/nfs/var/nfs type nfs (rw,addr=192.168.0.100)
client:~#

5 Testing

On the client, you can now try to create test files on the NFS shares:

client:

touch /mnt/nfs/home/test.txt
touch /mnt/nfs/var/nfs/test.txt

Now go to the server and check if you can see both test files:

server:

ls -l /home/

server:~# ls -l /home/
total 4
drwxr-xr-x 2 administrator administrator 4096 2007-04-23 14:25 administrator
-rw-r--r-- 1 root          root             0 2007-11-29 21:43 test.txt
server:~#

ls -l /var/nfs

server:~# ls -l /var/nfs
total 0
-rw-r--r-- 1 nobody nogroup 0 2007-11-29 21:49 test.txt
server:~#

(Please note the different ownerships of the test files: the /home NFS share gets accessed as root, therefore /home/test.txt is owned by root; the /var/nfs share gets accessed as nobody, therefore /var/nfs/test.txt is owned by nobody.)

6 Mounting NFS Shares At Boot Time

Instead of mounting the NFS shares manually on the client, you could modify /etc/fstab so that the NFS shares get mounted automatically when the client boots.

client:

Open /etc/fstab and append the following lines:

vi /etc/fstab

[...]
192.168.0.100:/home  /mnt/nfs/home   nfs      rw,sync,hard,intr  0     0
192.168.0.100:/var/nfs  /mnt/nfs/var/nfs   nfs      rw,sync,hard,intr  0     0

Instead of rw,sync,hard,intr you can use different mount options. To learn more about available options, take a look at

man nfs

To test if your modified /etc/fstab is working, reboot the client:

reboot

After the reboot, you should find the two NFS shares in the outputs of

df -h

client:~# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1              30G  748M   27G   3% /
tmpfs                  63M     0   63M   0% /lib/init/rw
udev                   10M   52K   10M   1% /dev
tmpfs                  63M     0   63M   0% /dev/shm
192.168.0.100:/home    30G  764M   27G   3% /mnt/nfs/home
192.168.0.100:/var/nfs
                       30G  764M   27G   3% /mnt/nfs/var/nfs
client:~#

and

mount

client:~# mount
/dev/sda1 on / type ext3 (rw,errors=remount-ro)
tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
udev on /dev type tmpfs (rw,mode=0755)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620)
192.168.0.100:/home on /mnt/nfs/home type nfs (rw,sync,hard,intr,addr=192.168.0.100)
192.168.0.100:/var/nfs on /mnt/nfs/var/nfs type nfs (rw,sync,hard,intr,addr=192.168.0.100)
client:~#

7 Links

• Linux NFS: http://nfs.sourceforge.net
• Debian: http://www.debian.org