AUTO_MASTER(5)						      BSD File Formats Manual						    AUTO_MASTER(5)

NAME

     auto_master -- auto_master and map file format

DESCRIPTION

     The automounter configuration consists of the auto_master configuration file, which assigns filesystem paths to map names, and maps, which
     contain actual mount information.	The auto_master configuration file is used by the automount(8) command.  Map files are read by the
     automountd(8) daemon.

AUTO_MASTER SYNTAX
     The auto_master file consists of lines with two or three entries separated by whitespace and terminated by newline character:

	   mountpoint map_name [-options]

     mountpoint is either a fully specified path, or /-.  When mountpoint is a full path, map_name must reference an indirect map.  Otherwise,
     map_name must reference a direct map.  See MAP SYNTAX below.

     map_name specifies map to use.  If map_name begins with -, it specifies a special map.  See MAP SYNTAX below.  If map_name is not a fully
     specified path (it does not start with /), automountd(8) will search for that name in /etc.  Otherwise it will use the path as given.  If the
     file indicated by map_name is executable, automountd(8) will assume it is an executable map.  See MAP SYNTAX below.  Otherwise, the file is
     opened and the contents parsed.

     -options is an optional field that starts with - and can contain generic filesystem mount options.

     The following example specifies that the /etc/auto_example indirect map will be mounted on /example.

	   /example auto_example

MAP SYNTAX

     Map files consist of lines with a number of entries separated by whitespace and terminated by newline character:

	   key [-options] [mountpoint [-options]] location [...]

     In most cases, it can be simplified to:

	   key [-options] location

     key is the path component used by automountd(8) to find the right map entry to use.  It is also used to form the final mountpoint.  A wild-
     card ('*') can be used for the key.  It matches every directory that does not match other keys.  Those directories will not be visible to the
     user until accessed.

     The options field, if present, must begin with -.	When mounting the filesystem, options supplied to auto_master and options specified in the
     map entry are concatenated together.  The special option fstype is used to specify filesystem type.  It is not passed to the mount program as
     an option.  Instead, it is passed as an argument to mount -t.  The default fstype is 'nfs'.  The special option nobrowse is used to disable
     creation of top-level directories for special and executable maps.

     The optional mountpoint field is used to specify multiple mount points for a single key.

     The location field specifies the filesystem to be mounted.  Ampersands ('&') in the location field are replaced with the value of key.  This
     is typically used with wildcards, like:

	   *	   192.168.1.1:/share/&

     The location field may contain references to variables, like:

	   sys	   192.168.1.1:/sys/${OSNAME}

     Defined variables are:

     ARCH     Expands to the output of uname -p.
     CPU      Same as ARCH.
     HOST     Expands to the output of uname -n.
     OSNAME   Expands to the output of uname -s.
     OSREL    Expands to the output of uname -r.
     OSVERS   Expands to the output of uname -v.

     Additional variables can be defined with the -D option of automount(8) and automountd(8).

     To pass a location that begins with /, prefix it with a colon.  For example, :/dev/cd0.

     This example, when put into /etc/auto_example, and with auto_master referring to the map as described above, specifies that the NFS share
     192.168.1.1:/share/example/x will be mounted on /example/x/ when any process attempts to access that mountpoint, with intr and nfsv4 mount
     options, described in mount_nfs(8):

	   x -intr,nfsv4 192.168.1.1:/share/example/x

     Automatically mount an SMB share on access, as a guest user, without prompting for a password:

	   share -fstype=smbfs,-N ://@server/share

     Automatically mount the CD drive on access:

	   cd -fstype=cd9660 :/dev/cd0

SPECIAL MAPS

     Special maps have names beginning with -.	Supported special maps are:

     -hosts  Query the remote NFS server and map exported shares.  This map is traditionally mounted on /net.  Access to files on a remote NFS
	     server is provided through the /net/nfs-server-ip/share-name Ns/ directory without any additional configuration.  Directories for
	     individual NFS servers are not present until the first access, when they are automatically created.
     -media  Query devices that are not yet mounted, but contain valid filesystems.  Generally used to access files on removable media.
     -null   Prevent automountd(8) from mounting anything on the mountpoint.

     It is possible to add custom special maps by adding them, as executable maps named special_foo, to the /etc/autofs/ directory.

EXECUTABLE MAPS

     If the map file specified in auto_master has the execute bit set, automountd(8) will execute it and parse the standard output instead of
     parsing the file contents.  When called without command line arguments, the executable is expected to output a list of available map keys
     separated by newline characters.  Otherwise, the executable will be called with a key name as a command line argument.  Output from the exe-
     cutable is expected to be the entry for that key, not including the key itself.

INDIRECT VERSUS DIRECT MAPS

     Indirect maps are referred to in auto_master by entries with a fully qualified path as a mount point, and must contain only relative paths as
     keys.  Direct maps are referred to in auto_master by entries with /- as the mountpoint, and must contain only fully qualified paths as keys.
     For indirect maps, the final mount point is determined by concatenating the auto_master mountpoint with the map entry key and optional map
     entry mountpoint.	For direct maps, the final mount point is determined by concatenating the map entry key with the optional map entry mount-
     point.

     The example above could be rewritten using direct map, by placing this in auto_master:

	   /- auto_example

     and this in /etc/auto_example map file:

	   /example/x -intr,nfsv4 192.168.1.1:/share/example/x
	   /example/share -fstype=smbfs,-N ://@server/share
	   /example/cd -fstype=cd9660 :/dev/cd0

DIRECTORY SERVICES

     Both auto_master and maps may contain entries consisting of a plus sign and map name:

	   +auto_master

     Those entries cause automountd(8) daemon to retrieve the named map from directory services (like LDAP) and include it where the entry was.

     If the file containing the map referenced in auto_master is not found, the map will be retrieved from directory services instead.

     To retrieve entries from directory services, automountd(8) daemon runs /etc/autofs/include, which is usually a shell script, with map name as
     the only command line parameter.  The script should output entries formatted according to auto_master or automounter map syntax to standard
     output.  An example script to use LDAP is included in /etc/autofs/include_ldap.  It can be symlinked to /etc/autofs/include.

FILES

     /etc/auto_master  The default location of the auto_master file.
     /etc/autofs/      Directory containing shell scripts to implement special maps and directory services.

SEE ALSO

     autofs(5), automount(8), automountd(8), autounmountd(8)

AUTHORS

     The auto_master configuration file functionality was developed by Edward Tomasz Napierala <trasz@FreeBSD.org> under sponsorship from the
     FreeBSD Foundation.

BSD
								  January 9, 2015							       BSD