Most Linux file systems are mounted at boot and remain mounted while the system is running. This is also true of any remote file systems that have been configured in the `fstab` file. However, there may be times when you prefer to have a remote file system mount only on demand—for example, to boost performance by reducing network bandwidth usage, or to hide or obfuscate certain directories for security reasons. The package [autofs][1] provides this feature. In this article, I'll describe how to get a basic automount configuration up and running.
`tree.mydatacenter.net` is up and running. Also assume a data directory named `ourfiles` and two user directories, for Carl and Sarah, are being shared by this server.
First, a few assumptions: Assume the NFS server namedis up and running. Also assume a data directory namedand two user directories, for Carl and Sarah, are being shared by this server.
A few best practices will make things work a bit better: It is a good idea to use the same user ID for your users on the server and any client workstations where they have an account. Also, your workstations and server should have the same domain name. Checking the relevant configuration files should confirm.
```
alan@workstation1:~$ sudo getent passwd carl sarah
As you can see, both the client workstation and the NFS server are configured in the `hosts` file. I’m assuming a basic home or even small office network that might lack proper internal domain name service (i.e., DNS).
### Install the packages
You need to install only two packages: `nfs-common` for NFS client functions, and `autofs` to provide the automount function.
Second, add the following line to the file `auto.misc`:
```
ourfiles -fstype=nfs tree:/share/ourfiles
```
This line instructs autofs to mount the `ourfiles` share at the location matched in the `auto.master` file for `auto.misc`. As shown above, these files will be available in the directory `/mnt/tree/ourfiles`.
Third, create the file `auto.home` with the following line:
```
* -fstype=nfs tree:/home/&
```
This line instructs autofs to mount the users share at the location matched in the `auto.master` file for `auto.home`. In this case, Carl and Sarah's files will be available in the directories `/home/tree/carl` or `/home/tree/sarah`, respectively. The asterisk (referred to as a wildcard) makes it possible for each user's share to be automatically mounted when they log in. The ampersand also works as a wildcard representing the user's directory on the server side. Their home directory should be mapped accordingly in the `passwd` file. This doesn’t have to be done if you prefer a local home directory; instead, the user could use this as simple remote storage for specific files.
Finally, restart the `autofs` daemon so it will recognize and load these configuration file changes.
```
alan@workstation1:/etc$ sudo service autofs restart
```
### Testing autofs
If you change to one of the directories listed in the file `auto.master` and run the `ls` command, you won’t see anything immediately. For example, change directory `(cd)` to `/mnt/tree`. At first, the output of `ls` won’t show anything, but after running `cd ourfiles`, the `ourfiles` share directory will be automatically mounted. The `cd` command will also be executed and you will be placed into the newly mounted directory.
```
carl@workstation1:~$ cd /mnt/tree
carl@workstation1:/mnt/tree$ ls
carl@workstation1:/mnt/tree$ cd ourfiles
carl@workstation1:/mnt/tree/ourfiles$
```
To further confirm that things are working, the `mount` command will display the details of the mounted share.
```
carl@workstation1:~$ mount
tree:/mnt/share/ourfiles on /mnt/tree/ourfiles type nfs4 (rw,relatime,vers=4.0,rsize=131072,wsize=131072,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=10.10.1.22,local_lock=none,addr=10.10.1.5)
```
The `/home/tree` directory will work the same way for Carl and Sarah.
I find it useful to bookmark these directories in my file manager for quicker access.
