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NAME | DESCRIPTION | FORMAT | BUILTIN MAP -hosts | BUILTIN MAP -null | LDAP MAPS | LDAP AUTHENTICATION, ENCRYPTED AND CERTIFIED CONNECTIONS | EXAMPLE | SEE ALSO | AUTHOR | COLOPHON |
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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 @mapdir@/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 @confdir@/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 mas‐
ter map.
For indirect maps access is by using the path scheme:
/mount-point/key
where mount-point is one of the entries listed in the master map.
The key is a single directory component and is matched against en‐
tries 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 specifica‐
tion 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 inabili‐
ty 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]
mount-point
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.
map-type
Type of map used for this mount point. The following are
valid map types:
file The map is a regular text file.
program
The map is an executable program, which is passed a
key on the command line and returns an entry (every‐
thing 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 program.
yp The map is a NIS (YP) database.
nisplus
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 directo‐
ry 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
Format of the map data; currently the formats recognized
are sun, which is a subset of the Sun automounter map for‐
mat, 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.
map
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 hes‐
iod or the dn of an LDAP entry for maps of type ldap.
options
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:
-Dvariable=value
Replace variable with value in map substitutions.
-strict
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.
[no]browse
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 di‐
rectories 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 imple‐
mentations.
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 on‐
ly 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 di‐
rect 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 in‐
stead.
symlink
This option makes bind mounting use a symlink in‐
stead of an actual bind mount. It is an autofs spe‐
cific 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.
strictexpire
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 ap‐
plication accesses triggered by the expire itself.
slave, private or shared
This option allows mount propagation of bind mounts
to be set to slave, private or shared. This option
defaults to slave if no option is given. When using
multi-mounts that have bind mounts the bind mount
will have the same properties as its parent which is
commonly propagation shared. And if the mount target
is also propagation shared this can lead to a dead‐
lock when attempting to access the offset mounts.
When this happens an unwanted offset mount is propa‐
gated back to the target file system resulting in a
deadlock since the automount target is itself an
(unwanted) automount trigger. This option is an
autofs pseudo mount option that can be used in the
master map only.
-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 ei‐
ther 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 configu‐
ration.
--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 up‐
dated 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 ac‐
cessing /net/myserver will mount exports from myserver on directo‐
ries below /net/myserver.
NOTE: mounts done from a hosts map will be mounted with the "no‐
suid,nodev" options unless overridden by explicitly specifying the
"suid", "dev" options in the master map entry.
If "-null" is given as the map it is used to tell automount(8) to
ignore a subsequent master map entry with the given path.
It can be used for paths that appear in the master map or in di‐
rect mount maps (but not in direct mount maps themselves) or as a
key in an indirect mount map.
An indirect mount map key can be nulled. If so the map key is ig‐
nored and does not result in a mount attempt (essentially the key
lookup is abandoned early on).
An indirect mount map top level mount point path can be nulled. If
so no mounts from the nulled mount are performed (essentially it
isn't mounted).
Direct mount map path entries can be nulled. Since they must be
present at startup they are (notionally) part of the master map so
direct mount paths that use the -null map may be used in the mas‐
ter map to ignore subsequent direct mount map entries.
A nulled master map entry path will ignore a single subsequent
matching entry. Any matching entry following that will be treated
as it normally would be. An example use of this is allowing local
master map entries to override remote ones.
NOTE: If a duplicate master map entry path is seen (excluding
paths of null entries) it will be ignored and noted in the log,
that is the first encountered master map entry is used unless
there is a corresponding null 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 be used for subsequent lookups.
There are three common schemas in use:
nisMap
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 con‐
tains the information used by the automounter.
automountMap
The automountMap schema has two variations that differ in
the attribute used for the map key. Entries in the auto‐
mountMap schema are automount objects in the specified sub‐
tree, 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 con‐
figuration 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
specification will be ignored.
For amd format maps a different schema is used:
amdMap
The amdmap schema contains attributes amdmapName, amdmapKey
and amdmapValue where amdmapName contains the name of the
containing map, amdmapKey contains the map key and amdmap‐
Value contains the map entry.
LDAP authenticated binds, TLS encrypted connections and certifica‐
tion may be used by setting appropriate values in the autofs au‐
thentication configuration file and configuring the LDAP client
with appropriate settings. The default location of this file is
@mapdir@/autofs_ldap_auth.conf.
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" ?>
<autofs_ldap_sasl_conf
usetls="yes"
tlsrequired="no"
authrequired="no"
authtype="DIGEST-MD5"
user="xyz"
secret="abc"
/>
If TLS encryption is to be used the location of the Certificate
Authority certificate must be set within the LDAP client configu‐
ration in order to validate the server certificate. If, in addi‐
tion, a certified connection is to be used then the client cer‐
tificate 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 certifi‐
cate 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.
/- auto.data
/home /etc/auto.home
/mnt yp:mnt.map
This will generate two mountpoints for /home and /mnt and install
direct mount triggers for each entry in the direct mount map au‐
to.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.
To avoid making edits to @mapdir@/auto.master, @mapdir@/auto.mas‐
ter.d may be used. Files in that directory must have a ".autofs"
suffix, e.g. @mapdir@/auto.master.d/extra.autofs. Such files
contain lines of the same format as the auto.master file, e.g.
/foo /etc/auto.foo
/baz yp:baz.map
automount(8), autofs(5), autofs(8), autofs.conf(5),
autofs_ldap_auth.conf(5).
This manual page was written by Christoph Lameter <chris@wa‐
terf.org>, for the Debian GNU/Linux system. Edited by <hpa@trans‐
meta.com> and Ian Kent <raven@themaw.net> .
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
autofs@vger.kernel.org. This page was obtained from the project's
upstream Git repository
⟨git://git.kernel.org/pub/scm/linux/storage/autofs/autofs.git⟩ on
2025-02-02. (At that time, the date of the most recent commit
that was found in the repository was 2024-08-14.) If you discover
any rendering problems in this HTML version 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 manual page), send a
mail to man-pages@man7.org
11 Apr 2006 AUTO.MASTER(5)
Pages that refer to this page: autofs(5), autofs.conf(5), autofs_ldap_auth.conf(5), autofs(8), automount(8)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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