Provided by: autofs_5.1.8-1ubuntu3_amd64 
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 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:
/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 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.
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 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 (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.
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 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
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.
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 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 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.
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 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
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
properties 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 access 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 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 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.
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 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" options unless
overridden by explicitly specifying the "suid", "dev" options in the master map entry.
BUILTIN MAP -null
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 only be used for paths that appear in the master map (or in direct mount maps).
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.
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.
LDAP MAPS
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 contains 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 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:
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 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 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.
EXAMPLE
/- 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 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), autofs_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)