AUTO.MASTER(5) File Formats Manual AUTO.MASTER(5)
NAME
auto.master - Master Map for automounter consulted by autofs
DESCRIPTION
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 al-
ternate name may be given on the command line when running the auto-
mounter 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 config-
uration 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:
/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 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:
+[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 un-
necessary 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 auto-
mount point path in the master map which will be removed if
present.
FORMAT
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 in-
direct 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 (everything be-
sides 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 pro-
gram.
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 nota-
tion. The contents of files under given directory are in-
cluded 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 ig-
nored.
format
Format of the map data; currently the formats recognized are
sun, which is a subset of the Sun automounter map format, hes-
iod, 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.
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 hesiod 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 au-
tomount (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 directories for in-
direct mount maps so the map keys can be seen in a direc-
tory 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 poten-
tial performance problem. This option does the same as
the deprecated --ghost option, the browse option is pre-
ferred because it is used by other autofs implementa-
tions.
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 pre-
vent 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 individ-
ual 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.
symlink
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 en-
tries) or with individual map entries. The option is ig-
nored for direct mounts and non-root offest mount en-
tries.
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 scan-
ning the mount tree. Note that this doesn't completely
resolve the problem of expired automounts being immedi-
ately re-mounted due to application 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 prop-
erties as its parent which is commonly propagation
shared. And if the mount target is also propagation
shared this can lead to a deadlock when attempting to ac-
cess the offset mounts. When this happens an unwanted
offset mount is propagated back to the target file system
resulting in a deadlock since the automount target is it-
self 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 either on
the command line or in the configuration.
-n, --negative-timeout <seconds>
Set the timeout for caching failed key lookups. This op-
tion can be used to override the global default given ei-
ther on the command line or in the configuration.
--mode <octal_mode>
Set the directory mode for the base location of the aut-
ofs mount point. If this option is given, autofs will
chmod that directory with this mode.
BUILTIN MAP -hosts
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 up-
date. 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 "no-
suid,nodev,intr" options unless overridden by explicitly specifying the
"suid", "dev" or "nointr" options in the master map entry.
LDAP MAPS
If the map type ldap is specified the mapname is of the form [//server-
name/]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 speci-
fied subtree, where the cn attribute is the key (the wildcard
key is "/"), and the nisMapEntry attribute contains the informa-
tion used by the automounter.
automountMap
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 at-
tribute 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 lo-
cated 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 specifica-
tion 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 amdmapValue contains the
map entry.
LDAP AUTHENTICATION, ENCRYPTED AND CERTIFIED CONNECTIONS
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
/etc/autofs_ldap_auth.conf.
If this file exists it will be used to establish whether TLS or authen-
tication 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 Author-
ity certificate must be set within the LDAP client configuration in or-
der 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 sys-
tem 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 documenta-
tion for your installation will need to be consulted to get further in-
formation.
See autofs_ldap_auth.conf (5) for more information.
EXAMPLE
/- auto.data
/home /etc/auto.home
/mnt yp:mnt.map
This will generate two mountpoints for /home and /mnt and install di-
rect 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.
To avoid making edits to /etc/auto.master, /etc/auto.master.d may be
used. Files in that directory must have a ".autofs" suffix, e.g.
/etc/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
SEE ALSO
automount(8), autofs(5), autofs(8), autofs.conf(5), aut-
ofs_ldap_auth.conf(5).
AUTHOR
This manual page was written by Christoph Lameter <chris@waterf.org>,
for the Debian GNU/Linux system. Edited by <hpa@transmeta.com> and Ian
Kent <raven@themaw.net> .
11 Apr 2006 AUTO.MASTER(5)