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)