Copy From: http://linuxconfig.org/how-to-configure-nfs-on-linux
How to configure NFS on Linux
1. Introduction
The Network File System is certainly one of the most widely used network services. Network file system (NFS) is based on the Remote procedure call which allows the client to automatically mount remote file systems and therefore transparently provide an access to it as if the file system is local.
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2. Scenario
In this scenario we are going to export the file system from the an IP address 10.1.1.50 ( NFS server ) host and mount it on an a host with an IP address 10.1.1.55 ( NFS Client ). Both NFS server and NFS client will be running Ubuntu Linux.
3. Prerequisites
At this point, we assume that the NFS service daemon is already installed on your system, including portmap daemon on which NFS setup depends.
If you have not done so yet simply install nfs-common package on both NFS client and NFS server using using apt-get tool.
# apt-get install nfs-common
The command above will fetch and install all support files common to NFS client and NFS server including portmap.
Additionally we need to install extra package on our NFS server side.
apt-get install nfs-kernel-server
This package is the actual NFS daemon listenning on both UDP and TCP 2049 ports.
Execute rpcinfo -p to check correctness of your NFS installation and to actually confirm that NFS server is indeed running and accepting calls on a port 2049:
# rpcinfo -p | grep nfs
100003 2 udp 2049 nfs
100003 3 udp 2049 nfs
100003 4 udp 2049 nfs
100003 2 tcp 2049 nfs
100003 3 tcp 2049 nfs
100003 4 tcp 2049 nfs
Furthermore, before we start exporting and mounting NFS directories, your system needs to actually support network file system. To check whether your system supports NFS grep /proc/filesystems and search for nfs.
# cat /proc/filesystems | grep nfs nodev nfs nodev nfs4
If you do not see any output it means that NFS is not supported or the NFS module have not been loaded into your kernel. To load NFS module execute:
# modprobe nfs
When installed correctly, the NFS daemon should be now listening on both UDP and TCP 2049 port and portmap should be waiting for instructions on a port 111.
At this point you should have portmap listening on both NFS server and NFS client:
rpcinfo -p | grep portmap
100000 2 tcp 111 portmapper
100000 2 udp 111 portmapper
4. Server export file
All directories we want to share over the network using NFS need to be defined on the server side of this communication and more specifically they need to be defind with /etc/exports file. In the next section you will see most common NFS exports:
4.1. Most common exports options
Here are the most common NFS export techniques and options:
| /home/nfs/ 10.1.1.55(rw,sync) | export /home/nfs directory for host with an IP address 10.1.1.55 with read, write permissions, and synchronized mode |
| /home/nfs/ 10.1.1.0/24(ro,sync) | export /home/nfs directory for network 10.1.1.0 with netmask 255.255.255.0 with read only permissions and synchronized mode |
| /home/nfs/ 10.1.1.55(rw,sync) 10.1.1.10(ro,sync) | export /home/nfs directory for host with IP 10.1.1.55with read, write permissions, synchronized mode, and also export /home/nfs directory for another host with an IP address 10.1.1.10 with read only permissions and synchronized mode |
| /home/nfs/ 10.1.1.55(rw,sync,no_root_squash) | export /home/nfs directory for host with an IP address 10.1.1.55with read, write permissions, synchronized mode and the remote root user will be treated as a root and will be able to change any file and directory. |
| /home/nfs/ *(ro,sync) | export /home/nfs directory for any host with read only permissions and synchronized mode |
| /home/nfs/ *.linuxcareer.com(ro,sync) | export /home/nfs directory for any host within linuxconfig.org domain with a read only permission and synchronized mode |
| /home/nfs/ foobar(rw,sync) | export /home/nfs directory for hostname foobar with read, write permissions and synchronized mode |
4.2. Edit exports file
Now that we have familiarized our selfs with some NFS's export options we can define our first NFS export. Open up your favorite text editor, for example, vim and edit /etc/exports file by adding a line /home/nfs/ *(ro,sync) which will export /home/nfs directory for any host with read only permissions. Instead of text editor you can simply insert your NFS export line into /etc/exports file using echo command:
# echo '/home/nfs/ *(ro,sync)' > /etc/exports # tail -1 /etc/exports /home/nfs/ *(ro,sync)
Be sure that the directory you are about to export by NFS exists. You can also create a file inside the /home/nfs directory which will help you troubleshoot once you mount /home/nfs/ remotely.
# touch /home/nfs/nfs-test-file
NOTE: The default behavior of NFS kernel daemon is to include additional option to your export line which is "no_subtree_check". Be aware of this fact when you attempt to configure your NFS exports further.
4.3. Restart NFS daemon
Once you have edited /etc/exports file you need to restart your NFS daemon to apply any changes. Depending on your Linux distribution the restarting procedure of NFS may differ. Ubuntu and Debian users:
# /etc/init.d/nfs-kernel-server restart
Redhat and Fedora users
# /etc/init.d/nfs restart
If you later decide to add more NFS exports to the /etc/exports file, you will need to either restart NFS daemon or run command exportfs:
# exportfs -ra
5. Mount remote file system on client
First we need to create a mount point:
# mkdir /home/nfs_local
If you are sure that the NFS client and mount point are ready, you can run the mount command to mount exported NFS remote file system:
# mount 10.1.1.50:/home/nfs /home/nfs_local
In case that you need to specify a filesystem type you can do this by:
# mount -t nfs 10.1.1.50:/home/nfs /home/nfs_local
You may also get and an error message:
mount: mount to NFS server failed: timed out (retrying).
This may mean that your server supports higher NFS version and therefore you need to pass one extra argument to your nfs client mount command. In this example we use nfs version 3:
# mount -t nfs -o nfsvers=3 10.1.1.50:/home/nfs /home/nfs_local
In any case now you should be able to access a remote /home/nfs directory locally on your NFS client.
# ls /home/nfs_local/ nfs-test-file # cd /home/nfs_local/ # ls nfs-test-file # touch test touch: cannot touch `test': Read-only file system
The above output proves that a remote NFS export is mounted and that we can access it by navigating to a local /home/nfs_local/ directory. Please notice that the touch command reports that the filesystem is mounted as read-only which was exactly our intention.