AUTO.MASTER(5)                File Formats Manual               AUTO.MASTER(5)

       auto.master - Master Map for automounter consulted by autofs

       The auto.master map is consulted to set up automount managed mount
       points when the autofs(8) script is invoked or the automount(8) program
       is run. Each line describes a mount point and refers to an autofs map
       describing file systems to be mounted under the mount point.

       The default location of the master map is /etc/autofs/auto.master but
       an alternate name may be given on the command line when running the
       automounter and the default master map may changed by setting the
       MASTER_MAP_NAME configuration variable in /etc/default/autofs.  If the
       master map name has no path then the system Name Service Switch
       configuration will be consulted and each of the sources searched in
       line with the rules given in the Name Service Switch configuration.

       Access to mounts in maps is governed by a key.

       For direct maps the mount point is always specified as:


       and the key used within the direct map is the full path to the mount
       point. The direct map may have multiple entries in the master map.

       For indirect maps access is by using the path scheme:


       where mount-point is one of the entries listed in the master map. The
       key is a single directory component and is matched against entries in
       the map given in the entry (See autofs(5)).

       Additionally, a map may be included from its source as if it were
       itself present in the master map by including a line of the form:

       +[maptype[,format]:]map [options]

       and automount(8) will process the map according to the specification
       described below for map entries. Plus map inclusion is only permitted
       in file map sources.  Indirect map entries must be unique in the master
       map so second and subsequent entries for an indirect mount point are
       ignored by automount(8).

       NOTE:  autofs currently does not collapse multiple slashes in paths, so
              it is important to ensure paths used in maps are correct. If
              unnecessary multiple slashes are present in a path it can lead
              to unexpected failures such as an inability to expire
              automounts. An exception to this is a trailing slash at the end
              of the automount point path in the master map which will be
              removed if present.

       Master map entries have three fields separated by an arbitrary number
       of spaces or tabs. Lines beginning with # are comments. The first field
       is the mount point described above and the second field is the name of
       the map to be consulted for the mount point followed by the third field
       which contains options to be applied to all entries in the map.

       The format of a master map entry is:

       mount-point [map-type[,format]:]map [options]

              Base location for the autofs filesystem to be mounted.  For
              indirect maps this directory will be created (as with mkdir -p)
              and is removed when the autofs filesystem is umounted.

              Type of map used for this mount point.  The following are valid
              map types:

              file   The map is a regular text file.

                     The map is an executable program, which is passed a key
                     on the command line and returns an entry (everything
                     besides the key) on stdout if successful.  Optinally, the
                     keyword exec may be used as a synonym for program to
                     avoid confusion with amd formated maps mount type

              yp     The map is a NIS (YP) database.

                     The map is a NIS+ database.

              hesiod The map is a hesiod database whose filsys entries are
                     used for maps.

              ldap or ldaps
                     The map is stored in an LDAP directory. If ldaps is used
                     the appropriate certificate must be configured in the
                     LDAP client.

              multi  This map type allows the specification of multiple maps
                     separated by "--". These maps are searched in order to
                     resolve key lookups.

              dir    This map type can be used at + master map including
                     notation. The contents of files under given directory are
                     included to the master map. The name of file to be
                     included must be ended with ".autofs". A file will be
                     ignored if its name is not ended with the suffix. In
                     addition a dot file, a file which name is started with
                     "." is also ignored.

              Format of the map data; currently the formats recognized are
              sun, which is a subset of the Sun automounter map format,
              hesiod, for hesiod filesys entries and amd for amd formated map
              entries.  If the format is left unspecified, it defaults to sun
              for all map types except hesiod unless it is a top level amd
              mount that has a configuration entry for the mount point path,
              in which case the format used is amd.

              Name of the map to use.  This is an absolute UNIX pathname for
              maps of types file, dir, or program, and the name of a database
              in the case for maps of type yp, nisplus, or hesiod or the dn of
              an LDAP entry for maps of type ldap.

              Any remaining command line arguments without leading dashes (-)
              are taken as options (-o) to mount.  Arguments with leading
              dashes are considered options for the maps and are passed to
              automount (8).

              The sun format supports the following options:

                     Replace variable with value in map substitutions.

                     Treat errors when mounting file systems as fatal. This is
                     important when multiple file systems should be mounted
                     (`multimounts'). If this option is given, no file system
                     is mounted at all if at least one file system can't be

                     This is an autofs specific option that is a pseudo mount
                     option and so is given without a leading dash. Use of the
                     browse option pre-creates mount point directories for
                     indirect mount maps so the map keys can be seen in a
                     directory listing without being mounted. Use of this
                     option can cause performance problem if the indirect map
                     is large so it should be used with caution. The internal
                     program default is to enable browse mode for indirect
                     mounts but the default installed configuration overrides
                     this by setting BROWSE_MODE to "no" because of the
                     potential performance problem. This option does the same
                     as the deprecated --ghost option, the browse option is
                     preferred because it is used by other autofs

              nobind This is an autofs specific option that is a pseudo mount
                     option and so is given without a leading dash. It may be
                     used either in the master map entry (so it effects all
                     the map entries) or with individual map entries to
                     prevent bind mounting of local NFS filesystems. For
                     direct mount maps the option is only effective if
                     specified on the first direct map entry and is applied to
                     all direct mount maps in the master map. It is ignored if
                     given on subsequent direct map entries. It may be used on
                     individual map entries of both types. Preventing bind
                     mounts of NFS file systems can no longer be done by using
                     the "port=" option, the nobind option must be used

                     This option makes bind mounting use a symlink instead of
                     an actual bind mount. It is an autofs specific option
                     that is a pseudo mount option and so is given without a
                     leading dash. It may be used with indirect map entries
                     only, either in the master map (so it effects all map
                     entries) or with individual map entries. The option is
                     ignored for direct mounts and non-root offest mount

                     Use a strict expire policy for this automount. Using this
                     option means that last use of autofs directory entries
                     will not be updated during path walks so that mounts in
                     an automount won't be kept mounted by applications
                     scanning the mount tree. Note that this doesn't
                     completely resolve the problem of expired automounts
                     being immediately re-mounted due to application accesses
                     triggered by the expire itself.

              slave or private
                     This option allows mount propagation of bind mounts to be
                     set to either slave or private. This option may be needed
                     when using multi-mounts that have bind mounts that bind
                     to a file system that is propagation shared. This is
                     because the bind mount will have the same properties as
                     its target which causes problems for offset mounts. When
                     this happens an unwanted offset mount is propagated back
                     to the target file system resulting in a deadlock when
                     attempting to access the offset.  This option is an
                     autofs pseudo mount option that can be used in the master
                     map only. By default, bind mounts will inherit the mount
                     propagation of the target file system.

              -r, --random-multimount-selection
                     Enables the use of random selection when choosing a host
                     from a list of replicated servers. This option is applied
                     to this mount only, overriding the global setting that
                     may be specified on the command line.

              -w, --use-weight-only
                     Use only specified weights for server selection where
                     more than one server is specified in the map entry. If no
                     server weights are given then each available server will
                     be tried in the order listed, within proximity.

              -t, --timeout <seconds>
                     Set the expire timeout for map entries. This option can
                     be used to override the global default given either on
                     the command line or in the configuration.

              -n, --negative-timeout <seconds>
                     Set the timeout for caching failed key lookups. This
                     option can be used to override the global default given
                     either on the command line or in the configuration.

              --mode <octal_mode>
                     Set the directory mode for the base location of the
                     autofs mount point.  If this option is given, autofs will
                     chmod that directory with this mode.

       If "-hosts" is given as the map then accessing a key under the mount
       point which corresponds to a hostname will allow access to the exports
       of that host. The hosts map cannot be dynamically updated and requires
       a HUP signal to be sent to the daemon for it to check hosts for an
       update. Due to possible hierarchic dependencies within a mount tree, it
       might not be completely updated during the HUP signal processing.

       For example, with an entry in the master map of /net -hosts accessing
       /net/myserver will mount exports from myserver on directories below

       NOTE: mounts done from a hosts map will be mounted with the
       "nosuid,nodev,intr" options unless overridden by explicitly specifying
       the "suid", "dev" or "nointr" options in the master map entry.

       If the map type ldap is specified the mapname is of the form
       [//servername/]dn, where the optional servername is the name of the
       LDAP server to query, and dn is the Distinguished Name of a subtree to
       search for map entries.  The old style ldap:servername:mapname is also
       understood. Alternatively, the type can be obtained from the Name
       Service Switch configuration, in which case the map name alone must be

       If no schema is set in the autofs configuration then autofs will check
       each of the commonly used schema for a valid entry and if one is found
       it will be used for subsequent lookups.

       There are three common schemas in use:

              Entries in the nisMap schema are nisObject objects in the
              specified subtree, where the cn attribute is the key (the
              wildcard key is "/"), and the nisMapEntry attribute contains the
              information used by the automounter.

              The automountMap schema has two variations that differ in the
              attribute used for the map key. Entries in the automountMap
              schema are automount objects in the specified subtree, where the
              cn or automountKey attribute (depending on local usage) is the
              key (the wildcard key is "/"), and the automountInformation
              attribute contains the information used by the automounter. Note
              that the cn attribute is case insensitive.

       The object classes and attributes used for accessing automount maps in
       LDAP can be changed by setting entries in the autofs configuration
       located in /etc/default/autofs.conf.

       NOTE:  If a schema is given in the configuration then all the schema
              configuration values must be set, any partial schema
              specification will be ignored.

       For amd format maps a different schema is used:

              The amdmap schema contains attributes amdmapName, amdmapKey and
              amdmapValue where amdmapName contains the name of the containing
              map, amdmapKey contains the map key and amdmapValue contains the
              map entry.

       LDAP authenticated binds, TLS encrypted connections and certification
       may be used by setting appropriate values in the autofs authentication
       configuration file and configuring the LDAP client with appropriate
       settings.  The default location of this file is

       If this file exists it will be used to establish whether TLS or
       authentication should be used.

       An example of this file is:

         <?xml version="1.0" ?>

       If TLS encryption is to be used the location of the Certificate
       Authority certificate must be set within the LDAP client configuration
       in order to validate the server certificate. If, in addition, a
       certified connection is to be used then the client certificate and
       private key file locations must also be configured within the LDAP

       In OpenLDAP these may be configured in the ldap.conf file or in the
       per-user configuration. For example, it may be sensible to use the
       system wide configuration for the location of the Certificate Authority
       certificate and set the location of the client certificate and private
       key in the per-user configuration. The location of these files and the
       configuration entry requirements is system dependent so the
       documentation for your installation will need to be consulted to get
       further information.

       See autofs_ldap_auth.conf (5) for more information.

         /home     /etc/auto.home

       This will generate two mountpoints for /home and /mnt and install
       direct mount triggers for each entry in the direct mount map
       All accesses to /home will lead to the consultation of the map in
       /etc/auto.home and all accesses to /mnt will consult the NIS map  All accesses to paths in the map will trigger
       mounts when they are accessed and the Name Service Switch configuration
       will be used to locate the source of the map

       To avoid making edits to /etc/autofs/auto.master,
       /etc/autofs/auto.master.d may be used.  Files in that directory must
       have a ".autofs" suffix, e.g.  /etc/autofs/auto.master.d/extra.autofs.
       Such files contain lines of the same format as the auto.master file,

         /foo    /etc/

       automount(8), autofs(5), autofs(8), autofs.conf(5),

       This manual page was written by Christoph Lameter <>,
       for the Debian GNU/Linux system. Edited by <> and Ian
       Kent <> .

                                  11 Apr 2006                   AUTO.MASTER(5)