Ubuntu Networking :: Automatically Mount NFS Shares Without Autofs?

Setup clients on a LAN to automatically mount NFS shares whenever the fileserver is up, without using autofs. Instead a simple bash script which checks if the server is up, and if the shares need to be mounted or unmounted is called by a custom upstart job. For a small office or home network populated with Unix-like computers (e.g., a few Ubuntu desktops or laptops and a fileserver), NFS (Network File System) is a good way to share storage space and centralise the backup of important documents. However, having a fileserver running 24/7 is often overkill for such a setup.

One way to have clients mount NFS shares automatically when the fileserver is turned on, is to use a package called autofs. Unfortunately, there are a few unresolved issues with using autofs in combination with NFS. In my case, when autofs tries to mount NFS shares when the fileserver is turned off, the Gnome desktop, and Nautilus in particular, becomes extremely unresponsive, regardless of the options used. Attempting to mount the share manually from the command line when the server is down however, does return a message of failure quite promptly, without hanging the desktop.

To solve this issue, I wrote a simple bash script that is run through the upstart system. The script simply checks if the fileserver is up, if the shares need mounting or unmounting, and then sleeps for a while before checking again. This works out quite well, so I decided to share this information in case someone else runs into these issues. PrerequisitesThis howto assumes that you have an NFS server set up with shares exported, and one or more clients capable of mounting those shares. For more information on setting up NFS shares and mounting them on a client from the command line, see: SettingUpNFSHowTo.

Clients should be able to ping the server to determine if it is running. Naturally, you need administrator access on the clients to install the script and upstart job outlined below. This script assumes that the directory paths of the shares match the location where they are mounted. In my case, the fileserver has two shares: /media/Storage and /media/Backup. On the clients these shares are mounted on the same paths. If your setup deviates from this, the script needs some modification. The script From the desktop of one the clients, paste the following bash script as a new file in your favourite text editor:

Code:

#!/bin/bash
# The hostname or IP-address of the fileserver:
FILESERVER="myfileserver.local"
# Check every X seconds (60 is a good default):

[code]...

Now adjust the FILESERVER variable. In this example, my fileserver is called myfileserver. By default, Ubuntu sets up your networking environment in such a way, that computername.local can be used to reach that computer over the local network, so the network name for myfileserver is myfileserver.local. Of course, you can also use the IP-address of the server. Next, change the MOUNTS variable to match the NFS shares exported by your NFS server. MOUNTS is an array; multiple entries are separated by spaces. So if you have one share exported as /media/MyShare, that line would look like this:

Code:

MOUNTS=( "/media/MyShare" )

An advantage of mounting shares in /media, is that they automatically show up as mounted drives on the user's desktop. Note that this howto assumes that you use the same paths for the share on the server and client side! Save the script to your desktop with an obvious name. In this example we call it mount_my_nfs_shares. Open a terminal and cd to the desktop. Make the script executable by calling:

Code:

chmod +x mount_my_nfs_shares

Next, move it to a place where it can be called by our upstart job, but also from the console to test. A good place to put such custom executables is /usr/local/bin.

Code:

sudo mv mount_my_nfs_shares /usr/local/bin

This script uses the logger command to tell the system's log what it is doing. To test this script, open up two terminals; in one, execute the following so we can monitor the log messages:

Code:

tail -f /var/log/syslog

In the other, simply execute mount_my_nfs_shares. If the script works, your shares should show up on the desktop and the computer:// location in Nautilus. If the fileserver goes down or becomes unreachable, the shares should disappear, and reappear when the fileserver comes back on-line. If this works, move on to the next step. Installing a custom upstart job The next step is to have the clients automatically run the above script when they are booted. We can use upstart for this. Create a new text file, and enter the following:

Code:

# mount_my_nfs_shares - mount NFS shares on fileserver, if present
description"Mount NFS-shares"
start on (filesystem)
respawn

[code]....

How the script works The script enters an eternal loop and keeps checking if it can reach the fileserver once every minute (unless you adjust the INTERVAL variable). If it can reach (ping) the fileserver, it checks if the mounts are already mounted by searching for them (grepping) in the output of mount. If they are not mounted, it tries to mount them. Else, if the server is down, it looks in the output of mount to see if these mounts exist. If they do, it tries to unmount them with the -f flag (useful for unmounting unreachable NFS shares).