Ubuntu Manpage: autofs - Format of the automounter maps

Provided by: autofs_5.0.7-3ubuntu3.2_amd64

NAME

       autofs - Format of the automounter maps

DESCRIPTION

       The automounter maps are FILE, NIS, NISPLUS or LDAP maps referred to by the master map of the automounter
       (see  auto.master(5)).   These  maps describe how file systems below the mount point of the map (given in
       the master map) are to be mounted.  This page describes the sun map format;  if  another  map  format  is
       specified (e.g. hesiod), this documentation does not apply.

       Indirect  maps,  except  for  the  internal  hosts map, can be changed on the fly and the automouter will
       recognize those changes on the next operation it performs on that map. Direct maps require a  HUP  signal
       be sent to the daemon to refresh their contents as does the master map.

FORMAT

This is a description of the text file format. Other methods of specifying these files may exist. All
empty lines or lines beginning with # are ignored. The basic format of one line in such maps is:

key [-options] location

key
For indirect mounts this is the part of the path name between the mount point and the path into the
filesystem when it is mounted. Usually you can think about the key as a sub-directory name below the
autofs managed mount point.

For direct mounts this is the full path of each mount point. This map is always associated with the /-
mount point in the master map.

options
Zero or more options may be given. Options can also be given in the auto.master file in which case both
values are cumulative (this is a difference from SunOS). The options are a list of comma separated
options as customary for the mount(8) command. There are two special options -fstype= used to specify a
filesystem type if the filesystem is not of the default NFS type. This option is processed by the
automounter and not by the mount command. -strict is used to treat errors when mounting file systems as
fatal. This is important when multiple file systems should be mounted (`multi-mounts'). If this option is
given, no file system is mounted at all if at least one file system can't be mounted. -use-weight-only
is used to make the weight the sole factor in selecting a server when multiple servers are present in a
map entry. and -no-use-weight-only can be used to negate the option if it is present in the master map
entry for the map but is not wanted for the given mount.

location
The location specifies from where the file system is to be mounted. In the most cases this will be an
NFS volume and the usual notation host:pathname is used to indicate the remote filesystem and path to be
mounted. If the filesystem to be mounted begins with a / (such as local /dev entries or smbfs shares) a
: needs to be prefixed (e.g. :/dev/sda1).

EXAMPLE

Indirect map:

kernel -ro,soft,intr ftp.kernel.org:/pub/linux
boot -fstype=ext2 :/dev/hda1
windoze -fstype=smbfs ://windoze/c
removable -fstype=ext2 :/dev/hdd
cd -fstype=iso9660,ro :/dev/hdc
floppy -fstype=auto :/dev/fd0
server -rw,hard,intr / -ro myserver.me.org:/ \
/usr myserver.me.org:/usr \
/home myserver.me.org:/home

In the first line we have a NFS remote mount of the kernel directory on ftp.kernel.org. This is mounted
read-only. The second line mounts an ext2 volume from a local ide drive. The third makes a share
exported from a Windows machine available for automounting. The rest should be fairly self-explanatory.
The last entry (the last three lines) is an example of a multi-map (see below).

If you use the automounter for a filesystem without access permissions (like vfat), users usually can't
write on such a filesystem because it is mounted as user root. You can solve this problem by passing the
option gid=<gid>, e.g. gid=floppy. The filesystem is then mounted as group floppy instead of root. Then
you can add the users to this group, and they can write to the filesystem. Here's an example entry for an
autofs map:

floppy-vfat -fstype=vfat,sync,gid=floppy,umask=002 :/dev/fd0

Direct map:

/nfs/apps/mozilla bogus:/usr/local/moxill
/nfs/data/budgets tiger:/usr/local/budgets
/tst/sbin bogus:/usr/sbin

FEATURES

   Map Key Substitution
       An  &  character  in  the location is expanded to the value of the key field that matched the line (which
       probably only makes sense together with a wildcard key).

   Wildcard Key
       A map key of * denotes a wild-card entry. This entry is consulted if the specified key does not exist  in
       the map.  A typical wild-card entry looks like this:

         *         server:/export/home/&

       The  special  character '&' will be replaced by the provided key.  So, in the example above, a lookup for
       the key 'foo' would yield a mount of server:/export/home/foo.

   Variable Substitution
       The following special variables will be substituted in the key and location fields of an automounter  map
       if prefixed with $ as customary from shell scripts (Curly braces can be used to separate the field name):

         ARCH           Architecture (uname -m)
         CPU            Processor Type
         HOST           Hostname (uname -n)
         OSNAME         Operating System (uname -s)
         OSREL          Release of OS (uname -r)
         OSVERS         Version of OS (uname -v)

       autofs provides additional variables that are set based on the user requesting the mount:

         USER           The user login name
         UID            The user login ID
         GROUP          The user group name
         GID            The user group ID
         HOME           The user home directory
         HOST           Hostname (uname -n)

       Additional entries can be defined with the -Dvariable=Value map-option to automount(8).

   Executable Maps
       A  map  can  be  marked  as executable. A program map will be called with the key as an argument.  It may
       return no lines of output if there's an error, or one or more  lines  containing  a  map  entry  (with  \
       quoting line breaks). The map entry corresponds to what would normally follow a map key.

       An  executable map can return an error code to indicate the failure in addition to no output at all.  All
       output sent to stderr is logged into the system logs.

   Multiple Mounts
       A multi-mount map can be used to name multiple filesystems to mount.  It takes the form:

         key [-options] [mount-point [-options] location...]...

       This may extend over multiple lines, quoting the line-breaks with `\´.  If  present,  the  per-mountpoint
       mount-options are appended to the default mount-options.

   Replicated Server
         Multiple replicated hosts, same path:
         <path> host1,host2,hostn:/path/path

         Multiple hosts, some with same path, some with another
         <path> host1,host2:/blah host3:/some/other/path

         Multiple replicated hosts, different (potentially) paths:
         <path> host1:/path/pathA host2:/path/pathB

         Mutliple weighted, replicated hosts same path:
         <path> host1(5),host2(6),host3(1):/path/path

         Multiple weighted, replicated hosts different (potentially) paths:
         <path> host1(3):/path/pathA host2(5):/path/pathB

         Anything else is questionable and unsupported, but these variations will also work:
         <path> host1(3),host:/blah

UNSUPPORTED

       This version of the automounter supports direct maps stored in FILE, NIS, NISPLUS and LDAP only.

AUTHOR

       This  manual  page  was written by Christoph Lameter <chris@waterf.org>, for the Debian GNU/Linux system.
       Edited by H.  Peter  Avian  <hpa@transmeta.com>,  Jeremy  Fitzhardinge  <jeremy@goop.org>  and  Ian  Kent
       <raven@themaw.net>.

                                                   14 Jan 2000                                         AUTOFS(5)