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automount(8)							 automount(8)



NAME

  automount - Automatically and	transparently mounts and unmounts NFS file
  systems

SYNOPSIS

  /usr/sbin/automount [-hmnpTv]	[-D name=value]	[-f master-file] [-M mount-
  directory] [-tl duration] [-tm interval] [-tw	interval] [directory map
  [-mount-options]]

OPTIONS

  -h  Includes the host	name in	mount-point pathnames.	The host name is
      inserted just after the mount-directory in a mount-point pathname.
      This ensures that	NFS mount points to different servers are placed in
      separate directories.  This avoids a limitation of getwd(3).

  -m  Ignores directory-mapname	pairs listed in	the auto.master	NIS database.

  -n  Disables dynamic mounts.	Lookups	intercepted by the automount daemon
      succeed only when	the target file	system has been	previously mounted.

  -p  Uses local mounts	for primary Internet addresses and NFS loopback
      mounts for Internet alias	addresses.  Without this option, the
      command's	default	behavior is to bypass NFS for all local	Internet
      addresses, including Internet alias addresses.

  -T  Traces all NFS requests received by the daemon.  Information about the
      details of the request are expanded and sent to standard output.

  -v  Logs status messages to the console.  (Stands for	"verbose.")

  -D name=value
      Defines an automount environment variable	by assigning value to the
      variable.

  -f master-file
      Uses master-file for a list of initial directory to mapname pairs,
      ahead of the auto.master NIS map.	 If an entry exists in both master-
      file and auto.master, the	one specified in master-file is	used since it
      is read first.  Similarly, entries on the	command	line take precedence
      over master-file entries.	 This technique	can be used to replace
      entries in global	maps with your own.

  -M mount-directory
      Uses mount-directory instead of the default, /tmp_mnt.

  -tl duration
      Specifies	a duration (in seconds)	that a file system is to remain
      mounted when not in use. The default is 5	minutes.

  -tm interval
      Specifies	an interval (in	seconds) between attempts to mount a file
      system. The default is 30	seconds.

  -tw interval
      Specifies	an interval (in	seconds) between attempts to unmount file
      systems that have	exceeded their cached times. The default is 1 minute.

  directory
      Specifies	the full pathname of a local directory if the map argument is
      the name of an indirect map or the name of a special map.	If the map
      argument is the name of a	direct map, the	dummy directory	"/-" is
      specified	as the directory.

  map Names a map that the automount command uses to find the mount points
      and locations.  This can either be a file	name, an NIS map name, or a
      special map name.

  -mount-options
      Specifies	the mount options to be	applied	to all of the directories
      listed in	map. If	mount options are listed in the	specified map, they
      take precedence over these options.

DESCRIPTION

  The automount	daemon automatically and transparently mounts and unmounts
  NFS file systems on an as-needed basis.  It provides an alternative to
  using	/etc/fstab for NFS mounting file systems on client machines.

  Note that the	automount daemon will be retired in a future release of	the
  operating system. For	information about migrating from Automount to its
  replacement, AutoFS, see Network Administration: Services.  For more infor-
  mation about AutoFS, see autofsd(8).

  The automount	daemon can be started from the /etc/rc.config.common file or
  from the command line.  Once started,	it sleeps until	a user attempts	to
  access a directory that is associated	with an	automount map, or any direc-
  tory or file in the directory	structure.  The	daemon awakes and consults
  the appropriate map and mounts the NFS file system. By default, the daemon
  mounts the remote file system	under the directory /tmp_mnt and creates a
  symbolic link	to the temporary mount point. If the indicated directory has
  not already been created, the	daemon creates it and removes it after
  automatic unmount. After a specified period of inactivity on a file system,
  5 minutes by default,	the automount daemon unmounts that file	system.

  The maps indicate where to find the file system to be	mounted	and the	mount
  options to use. The names of the maps	are passed to automount	from the com-
  mand line or from a master map.  If the command line and the master map
  contain contradictory	arguments, the command line arguments take pre-
  cedence.

				     Note

       The automount program reads the master map only at startup.  If you
       make any	changes	to the master map, you must restart automount.

  An individual	automount map is either	local or served	by NIS.	A system,
  however, can use both	local and NIS automount	maps.  When a map is refer-
  enced, the automount daemon checks whether a full pathname is	specified.
  If it	is, automount looks for	the designated mapname locally.	 If the	map-
  name is not a	full pathname, automount looks for an NIS map by that name.

  By default, automount	uses UDP.  If the tcp option is	specified in a map,
  automount will try TCP.  If TCP is not available, automount will then	use
  UDP.



  Maps


  Conventionally, automount maps are files that	are located in the /etc
  directory with names that have the prefix auto.  They	indicate which remote
  file systems to mount, where to mount	them, and which	options	to use.

  The Master Map


  The automount	program	can consult a master map, which	contains entries that
  point	to other maps that can be either direct	or indirect.  If NIS is	run-
  ning,	automount checks for the presence of an	NIS map	named auto.master;
  you are not required to run NIS or have an auto.master map. A	master map
  can also be a	file whose location is specified with the -f command line
  option.

  The master map provides automount with a list	of maps, and with arguments
  that pertain to each of the maps. Each line in the master map	has the	fol-
  lowing syntax:

  directory map	[mount-options]

  directory
      Specifies	the full pathname of a local directory if the map argument is
      the name of an indirect map or the name of a special map.	If the map
      argument is the name of a	direct map, the	dummy directory	"/-" is
      specified	as the directory.

  map Names the	map that the automount command uses to find the	mount points
      and locations.  This can either be a file	name, an NIS map name, or a
      special map name.

  mount-options
      Lists the	options	used to	regulate the mounting of entries listed	in
      map.

  Direct Maps


  Direct maps specify which remote file	systems	to mount locally and what the
  local	mount points are. They also can	specify	mount options. Direct maps
  have the following syntax:

  key [mount-options] location

  key Specifies	the full pathname of the mount point.

  mount-options
      Lists the	options	for this specific mount. When present, these options
      override any mount options specified on the command line or in the mas-
      ter map.

  location
      Specifies	the location of	the resource being mounted and uses the	for-
      mat server:pathname. Multiple location fields can	be specified; see
      Replicated File Systems for more information.









  Indirect Maps


  Indirect maps	have the same format as	direct maps. However, unlike the key
  in a direct map, the key in an indirect map is a simple name that does not
  begin	with a slash. (Remember	that the indirect map as a whole has been
  associated with a directory specified	in the master map or on	the command
  line.	 The entries in	an indirect map	list subdirectories that are indivi-
  dually mounted within	the directory associated with the map.)

  Special Maps


  The -hosts map is a special automount	map that is used to access all direc-
  tories exported by a server to a client.

  The following	command	allows a client	to access directories that are
  exported from	any host in its	/etc/hosts file, the NIS hosts database:

       # automount /net	-hosts

  For example, suppose that hera and sheba are both hosts on a local area
  network that is running NIS. If superuser on hera enters the automount /net
  -hosts command, users	on hera	can access any directories that	sheba exports
  to hera. All of the exported directories are mounted under /net/sheba	on
  hera.

  The -null map, when indicated	on the command line, cancels the map associ-
  ated with the	directory indicated.  It can be	used to	cancel a map speci-
  fied in the master map.  For example,	invoking the automount command in the
  following manner causes the /net entry in auto.master	to be ignored:

       # automount /net	-null

  Pattern Matching


  The ampersand	(&) is expanded	into the key field in a	map wherever it
  appears.  In the following example, the ampersand (&)	expands	to oak:

       #key	 mount_options	    location
       #
       oak			     &:/export/&

  The asterisk (*), when supplied as the key field, is recognized as the
  catch-all entry.  It is used to substitute for lines that are	all formatted
  similarly. Any entry following the asterisk is ignored. In the following
  example, the automount program uses the asterisk to match any	host name
  other	than oak:

       #key	    mount_options	 location
       #
       oak				 &:/export/&
       *				 &:/home/&

  Environment Variables


  The value of an environment variable can be used within an automount map by
  prefixing a dollar sign ($) to its name.  You	can also use braces to del-
  imit the name	of the variable	from appended letters or digits. The environ-
  ment variables can be	inherited from the environment or can be explicitly
  defined with the -D command line option.



  Multiple Mounts


  A multiple mount entry causes	several	NFS mount points to be mounted and
  unmounted together. Multiple mounts have the following syntax:

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

  [mountpoint [mount-options] location...] ...

  key Specifies	the full pathname or simple name of the	mount point, depend-
      ing on whether it	is a direct or indirect	map entry.

  mountpoint
      Specifies	the full pathname of a local directory.	All mount points must
      begin with a slash (/). A	slash is acceptable as the first mountpoint.

  mount-options
      Lists the	options	for this specific mount. When present, these options
      override any mount options specified on the command line or in the mas-
      ter map.

  location
      Specifies	the location of	the resource being mounted and uses the	for-
      mat server:pathname. Multiple location fields can	be specified; see
      Replicated File Systems for more information.

  If multiple mounts are hierarchically	related, the order in which they
  appear in the	entry is the order in which they are mounted.

  In the following example, the	directories /usr/local,	/usr/local/bin,
  /usr/local/src, and /usr/local/tools are mounted from	the machines host1,
  host2, host3,	and host4, respectively.  When the root	of the hierarchy is
  referenced, the automount program mounts the whole hierarchy.

       /usr/local \
	/	  -ro	    host1:/usr/local \
	/bin	  -ro	    host2:/usr/local/bin \
	/src	  -ro	    host3:/usr/local/src \
	/tools	  -ro	    host4:/usr/src/tools

  Readability has been improved	by splitting the entry into five lines and
  indenting the	continuation lines.

  Shared Mounts


  A shared mount prevents duplicate mounts of a	remote file system by creat-
  ing symbolic links for subdirectories	that the file system contains.	When
  you mount multiple directories from within a common remote directory,	you
  can specify the location field as follows:

  host:path:subdir

  host
      Specifies	the remote host	from which to mount the	file system.

  path
      Specifies	a pathname for the common directory that contains the direc-
      tories you want to mount.

  subdir
      Specifies	the name of a subdirectory to which you	want to	make a sym-
      bolic link.

  Suppose an indirect map called /auto.myindirect is specified in a master
  file as follows:

       /mydir	       /auto.myindirect


  And the /auto.myindirect map consists	of the following entries:

       mybin	       host1:/usr/staff/diane:bin
       mystuff	       host1:/usr/staff/diane:stuff

  When a user accesses a file in /mydir/mybin, the automount daemon mounts
  host1:/usr/staff/diane, but creates a	symbolic link called /mydir/mybin to
  the bin subdirectory in the temporarily mounted file system. If a user
  immediately tries to access a	file in	/mydir/mystuff,	the automount daemon
  needs	only to	create a symbolic link that points to the stuff	subdirectory
  because the /usr/staff/diane directory is already mounted.  With the fol-
  lowing map, the daemon would perform two separate mount operations:

       mybin	       host1:/usr/staff/diane/bin
       mystuff	       host1:/usr/staff/diane/stuff

  Replicated File Systems


  You can specify multiple locations for a single mount.  If a file system is
  located on several servers and one of	the servers is disabled, the file
  system can be	mounted	from one of the	other servers. This makes sense	only
  when mounting	a read-only file system.

  In the following example, the	reference pages	can be mounted from host1,
  machine2, or system3:

       /usr/man\
		       -ro,soft	       host1:/usr/man \
				       machine2:/usr/man \
				       system3:/usr/man

  The preceding	example	can also be expressed as a list	of servers, separated
  by commas and	followed by a colon and	the pathname, for example:

       /usr/man	 -ro,soft  host1,machine2,system3:/usr/man

  This syntax is valid only if the pathname is the same	on each	server.

  When you access the reference	pages, the automount daemon issues a ping
  (NFS v2 noop request)	to each	of the specified servers concurrently. The
  server that first responds to	the ping request is used for the mount.

NOTES

  Sending the SIGTERM signal (kill -TERM) to the automount daemon causes it
  to unmount all file systems that it has mounted, and to exit.	 This is the
  preferred method.  If	you send any other signals that	automount cannot
  catch	(for example, kill -KILL or kill -INT),	any NFS	mount points that
  automount was	not able to remove before exiting will hang.  The hang will
  occur	from any program that attempts to access those mount points.  You
  must reboot the system in order to remove the	NFS mount points.

  Sending the SIGHUP signal to the automount daemon causes it to reread	the
  system mount table to	update its internal record of currently	mounted	file
  systems.  If a file system mounted with automount is unmounted by a umount
  command, automount should be forced to reread	the system mount table.




RESTRICTIONS

  Shell	filename expansion does	not apply to objects not currently mounted.


  Because automount is singlethreaded, any request that	is delayed by a	slow
  or nonresponding NFS server will delay all subsequent	automount requests
  until	the delayed request has	been completed.

EXAMPLES

   1.  The following is	a sample auto.master map:


	    #
	    # mount-point	    mapname	      mount-options
	    #
	    /net		    -hosts
	    /home		    auto.indirect     -rw
	    /-			    auto.direct	      -ro,intr

   2.  The following is	a typical automount indirect map:


	    #
	    # key		mount-options	      location
	    #
	    john				      merge:/usr/staff/john
	    mary				      stripe:/usr/staff/mary
	    fred				      blur:/usr/staff/fred

   3.  The following is	a typical automount direct map:


	    #
	    # key		mount-options	      location
	    #
	    /usr/source		-ro		      merge:/usr/src/proto
	    /usr/local				      blur:/usr/bin/tools

   4.  The following is	a sample indirect map that specifies multiple mount
       locations for the file system reference.	The file system	is mounted
       from the	first server to	respond	to the mount request.


	    reference		-ro	       earl:/usr/src/ref\
					       fern:/usr/staff/ron/ref\
					       irv:/usr/backup/reference



FILES

  /tmp_mnt
      Directory	where automounted file systems reside.

SEE ALSO

  Commands: autofsd(8),	autofsmount(8),	mount(8)

  Network Administration: Services