Setting Up An NFS Server And Client On Debian Lenny

This guide explains how to set up an NFS server and an NFS client on Debian Lenny. 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,no_subtree_check) hostname2(ro,sync,no_subtree_check) # # Example for NFSv4: # /srv/nfs4 gss/krb5i(rw,sync,fsid=0,crossmnt,no_subtree_check) # /srv/nfs4/homes gss/krb5i(rw,sync,no_subtree_check) # /home 192.168.0.101(rw,sync,no_root_squash,no_subtree_check) /var/nfs 192.168.0.101(rw,sync,no_subtree_check)

(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/mapper/vg0-root 19G 676M 17G 4% /
tmpfs 253M 0 253M 0% /lib/init/rw
udev 10M 80K 10M 1% /dev
tmpfs 253M 0 253M 0% /dev/shm
/dev/sda1 471M 20M 427M 5% /boot
192.168.0.100:/home 29G 684M 27G 3% /mnt/nfs/home
192.168.0.100:/var/nfs
29G 684M 27G 3% /mnt/nfs/var/nfs
client:~#

and

mount

client:~# mount
/dev/mapper/vg0-root 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)
/dev/sda1 on /boot type ext3 (rw)
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 2009-02-16 13:18 administrator
-rw-r--r-- 1 root root 0 2009-03-12 17:08 test.txt
server:~#

ls -l /var/nfs

server:~# ls -l /var/nfs
total 0
-rw-r--r-- 1 nobody nogroup 0 2009-03-12 17:08 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/mapper/vg0-root 19G 676M 17G 4% /
tmpfs 253M 0 253M 0% /lib/init/rw
udev 10M 80K 10M 1% /dev
tmpfs 253M 0 253M 0% /dev/shm
/dev/sda1 471M 20M 427M 5% /boot
192.168.0.100:/home 29G 684M 27G 3% /mnt/nfs/home
192.168.0.100:/var/nfs
29G 684M 27G 3% /mnt/nfs/var/nfs
client:~#

and

mount

client:~# mount
/dev/mapper/vg0-root 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)
/dev/sda1 on /boot type ext3 (rw)
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