The default master configuration file for autofs is /etc/auto.master. You can change its location by changing the value of the DEFAULT_MASTER_MAP_NAME option in /etc/sysconfig/autofs. Here is the content of the default one for openSUSE Leap:

#
# Sample auto.master file
# This is an automounter map and it has the following format
# key [ -mount-options-separated-by-comma ] location
# For details of the format look at autofs(5).1
#
#/misc  /etc/auto.misc2
#/net -hosts
#
# Include /etc/auto.master.d/*.autofs3
#
#+dir:/etc/auto.master.d
#
# Include central master map if it can be found using
# nsswitch sources.
#
# Note that if there are entries for /net or /misc (as
# above) in the included master map any keys that are the
# same will not be seen as the first read key seen takes
# precedence.
#
+auto.master4

Entries in auto.master have three fields with the following syntax:

mount point      map name      options

Tip: More information

For more detailed information on the specific values of the optional map-type, format, and options, see the auto.master manual page (man 5 auto.master).

The following entry in auto.master tells autofs to look in /etc/auto.smb, and create mount points in the /smb directory:

/smb   /etc/auto.smb

23.2.1.1 Direct mounts #Edit source

• File Name: autofs.xml
• ID: sec-autofs-directmount

Direct mounts create a mount point at the path specified inside the relevant map file. Instead of specifying the mount point in auto.master, replace the mount point field with /-. For example, the following line tells autofs to create a mount point in the place specified in auto.smb:

/-        /etc/auto.smb

Tip: Maps without full path

If the map file is not specified with its full local or network path, it is located using the Name Service Switch (NSS) configuration:

/-        auto.smb

Important: Other types of maps

Although files are the most common types of maps for auto-mounting with autofs, there are other types as well. A map specification can be the output of a command, or a result of a query in LDAP or a database. For more detailed information on map types, see the manual page man 5 auto.master.

Map files specify the (local or network) source location, and the mount point where to mount the source locally. The general format of maps is similar to the master map. The difference is that the options appear between the mount point and the location instead of at the end of the entry:

mount point      options      location

Make sure that map files are not marked as executable. You can remove the executable bits by executing chmod -x MAP_FILE.

The operation of the autofs service is controlled by systemd. The general syntax of the systemctl command for autofs is

> sudo systemctl SUB_COMMAND autofs

where SUB_COMMAND is one of:

If you experience problems when mounting directories with autofs, it is useful to run the automount daemon manually and watch its output messages:

This helper mount point is useful if you use a lot of NFS shares. /net auto-mounts all NFS shares on your local network on demand. The entry is already present in the auto.master file, so all you need to do is uncomment it and restart autofs:

/net      -hosts

> sudo systemctl restart autofs

For example, if you have a server named jupiter with an NFS share called /export, you can mount it by typing

> sudo cd /net/jupiter/export

on the command line.

If you have a directory with subdirectories that you need to auto-mount individually—the typical case is the /home directory with individual users' home directories inside—autofs offers a clever solution.

In case of home directories, add the following line in auto.master:

/home      /etc/auto.home

Now you need to add the correct mapping to the /etc/auto.home file, so that the users' home directories are mounted automatically. One solution is to create separate entries for each directory:

wilber      jupiter.com:/home/wilber
penguin      jupiter.com:/home/penguin
tux      jupiter.com:/home/tux
[...]

This is very awkward as you need to manage the list of users inside auto.home. You can use the asterisk '*' instead of the mount point, and the ampersand '&' instead of the directory to be mounted:

*      jupiter:/home/&

If you want to auto-mount an SMB/CIFS share (see Chapter 21, Samba for more information on the SMB/CIFS protocol), you need to modify the syntax of the map file. Add -fstype=cifs in the option field, and prefix the share location with a colon ':'.

mount point      -fstype=cifs      ://jupiter.com/export