Provided by: autofs_5.1.5-1ubuntu1_amd64 bug


       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/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

       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. 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.
                     Optionally, the keyword exec may be used as a synonym for program  to  avoid
                     confusion with amd formatted maps mount type program.

              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  formatted  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 implementations.

              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 instead.

                     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 entries.

              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  a  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

              --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 /net/myserver.

       NOTE:  mounts  done  from a hosts map will be mounted with the "nosuid,nodev,intr" options
       unless overridden by explicily 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 given.

       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  used  for  subsequent

       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

       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 client.

       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


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