The auto.master map is consulted to set up automount managed mount
points when the autofs(8) script is invoked or the automount(8) pro‐
gram is run. Each line describes a mount point and refers to an aut‐
ofs map describing file systems to be mounted under the mount point.
The default location of the master map is @mapdir@/auto.master but an
alternate name may be given on the command line when running the au‐
tomounter and the default master map may changed by setting the
MASTER_MAP_NAME configuration variable in @confdir@/autofs. If the
master map name has no path then the system Name Service Switch con‐
figuration 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 it‐
self present in the master map by including a line of the form:
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).
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 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 mounted.
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
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. Bind mounting of NFS file systems can also
be prevented for specific map entrys by adding the
"port=" mount option to the entries.
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.
Enables the use of ramdom 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.
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.
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
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 "no‐
suid,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 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 automountInforma‐tion attribute contains the information used by the auto‐
mounter. 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 @confdir@/autofs.conf.
NOTE: If a schema is given in the configuration then all the schema
configuration values must be set, any partial schema specifi‐
cation 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 con‐
taining map, amdmapKey contains the map key and amdmapValue
contains the map entry.
LDAP AUTHENTICATION, ENCRYPTED AND CERTIFIED CONNECTIONS top
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 au‐
thentication 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 Au‐
thority certificate must be set within the LDAP client configuration
in order to validate the server certificate. If, in addition, a cer‐
tified connection is to be used then the client certificate and pri‐
vate 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 Author‐
ity 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.
This will generate two mountpoints for /home and /mnt and install
direct mount triggers for each entry in the direct mount map
auto.data. 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 mnt.map. All accesses to paths in the map auto.data will
trigger mounts when they are accessed and the Name Service Switch
configuration will be used to locate the source of the map auto.data.
This page is part of the autofs (automount) project. Information
about the project can be found at ⟨http://www.autofs.org/⟩. If you
have a bug report for this manual page, send it to
email@example.com. This page was obtained from the project's
upstream Git repository
2017-03-13. If you discover any rendering problems in this HTML ver‐
sion of the page, or you believe there is a better or more up-to-date
source for the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original man‐
ual page), send a mail to firstname.lastname@example.org
11 Apr 2006 AUTO.MASTER(5)