automount(1M)automount(1M)NAMEautomount - install automatic mount points
SYNOPSIS
master-file] duration]
DESCRIPTION
The command installs mount points and associates an map with each mount
point. The filesystem monitors attempts to access directories within
it and notifies the daemon (see automountd(1M)). The daemon uses the
map to locate a filesystem, which it then mounts at the point of refer‐
ence within the filesystem. You can assign a map to an mount using an
entry in the map or a direct map.
If the filesystem is not accessed within an appropriate interval (10
minutes by default), the daemon unmounts the file system.
The file determines the locations of all mount points. By default,
this file contains the following entry:
The first field in the master file specifies a directory on which an
mount will be made, and the second field specifies the automounter map
to be associated with it. Mount options may be supplied as an optional
third field in the entry. These options are used for any entries in
the map that do not specify mount options explicitly. The command is
usually run without arguments. It compares the entries with the cur‐
rent list of mounts in and adds, removes, or updates mounts to bring
the up to date with the At boot time, it installs all mounts from the
master map. Subsequently, it may be run to install mounts for new
entries in the master map or a direct map, or to perform unmounts for
entries that have been removed.
If the first field specifies the directory as treats the second field
as the name of a direct map. In a direct map, each entry associates
the full path name of a mount point with a remote file system to mount.
If the first field is a path name, the second field names an indirect
map or a special map (described below). An indirect map contains a
list of the subdirectories within the indicated directory. With an
indirect map, it is these subdirectories that are mounted automati‐
cally.
The automounter maps, including the auto_master map, may be distributed
by NIS or LDAP. The Name Service Switch configuration file, determines
where the command will look for the maps.
Options
recognizes the following options:
Specify a local master file for initialization.
When the option is used and the master file spec‐
ified is not found, then defaults to and then to
the NIS map.
Specify a duration, in seconds, that a file system is to
remain mounted when not in use. The default is
600 (10 minutes). The new duration value will
apply to new mount points and their associated
mounts. Note that setting a new duration does
not affect any existing mount points or associ‐
ated mounts. In order for the new duration to
take effect, an existing mount point must first
be unmounted, then remounted.
Verbose mode. Notify of mounts, unmounts, or other non-essen‐
tial information. Messages are written to stan‐
dard error.
Map Entry Format
A simple map entry (mapping) takes the form:
where key is the full path name of the directory to mount when used in
a direct map, or the simple name of a subdirectory in an indirect map.
mount-options is a comma-separated list of mount options, and location
specifies a file system from which the directory may be mounted. In
the case of a simple NFS mount, the options that can be used are as
specified in mount_nfs(1M), and location takes the form:
host is the name of the host from which to mount the file system and
pathname is the path name of the directory to mount.
Default mount options can be assigned to an entire map when specified
as an optional third field in the master map. These options apply only
to map entries that have no mount options.
Replicated Filesystems
Multiple location fields can be specified for replicated NFS filesys‐
tems, in which case the information is used to try to increase avail‐
ability. The server chosen for the mount is the one with the strongest
preference based on a sorting order. Note that does not monitor the
status of mounts when dealing with replicated filesystems and does not
select alternate servers.
The sorting order used gives strongest preference to servers on the
same local subnet with servers on the local net given the second
strongest preference. Among servers equally far away, response times
will determine the order if no weighting factors are used (see below).
If the list of locations contains some servers using the NFS Version 2
Protocol and some servers using the NFS Version 3 Protocol, then will
choose a subset of the list having only servers with the same protocol.
This subset is formed of servers using the NFS Version 3 Protocol
unless there are no such servers on the list or there is a server using
the NFS Version 2 Protocol that has the strongest preference as
described previously.
If each location in the list shares the same pathname then a single
location may be used with a comma-separated list of hostnames:
Requests for a server may be weighted, with the weighting factor
appended to the server name as an integer in parentheses. Servers
without a weighting default to a value of zero (most likely to be
selected). Progressively higher values decrease the chance of being
selected. In the example,
hosts and have the highest priority; host has the lowest priority.
NOTE: Server proximity takes priority in the selection process. In
the example above, if the server is on the same network segment
as the client, but the others are on different network segments,
then will be selected; the weighting value is ignored. The
weighting has effect only when selecting between servers with
the same network proximity.
In cases where each server has a different export point, you can still
apply the weighting. For example:
A mapping can be continued across input lines by escaping the newline
with a backslash Comments begin with a number sign and end at the sub‐
sequent newline.
Map Key Substitution
The ampersand character is expanded to the value of the key field for
the entry in which it occurs. In this case:
the expands to
Wildcard Key
The asterisk character, when supplied as the key field, is recognized
as the catch-all entry. Such an entry will match any key not previ‐
ously matched. For instance, if the following entry appeared in the
indirect map for
it would allow automatic mounts in of any remote file system whose
location could be specified as:
Variable Substitution
Client specific variables can be used within an map. For instance, if
appeared within a map, would expand it to its current value for the
client's host name. Supported variables are:
The processor type.
The possible values are:
The output of
The host name. For example,
The output of
The OS name. For example,
The output of
The OS release name. For example,
The output of
The OS version. For example,
If a reference needs to be protected from neighboring characters, you
can surround the variable name with braces
Multiple Mounts
A multiple mount entry takes the form:
key mount-options] [[mountpoint] mount-options] location]...
The initial mountpoint] is optional for the first mount and mandatory
for all subsequent mounts. The optional mountpoint is taken as a path
name relative to the directory named by key. If mountpoint is omitted
in the first occurrence, a mountpoint of (root) is implied.
Given an entry in the indirect map for
All offsets must already exist on the server under would automatically
mount and as needed, from either or whichever host is nearest and
responds first.
The mount points must not be hierarchically related. does not allow an
mount point to be created within another mount.
Other Filesystem Types
The automounter assumes NFS mounts as a default filesystem type. Other
filesystem types can be described using the mount option. Other mount
options specific to this filesystem type can be combined with the
option. The location field must contain information specific to the
filesystem type. If the location field begins with a slash, a colon
character must be prepended, for instance, to mount a CD filesystem:
or to perform an mount:
Mounts using CacheFS are most useful when applied to an entire map as
map defaults (see cfsadmin(1M)). The following entry in the master map
describes cached home directory mounts. It assumes the default loca‐
tion of the cache directory,
Indirect Maps
An indirect map allows you to specify mappings for the subdirectories
you wish to mount under the directory indicated in the map. In an
indirect map, each key consists of a simple name that refers to the
subdirectory of one or more filesystems that are to be mounted as
needed.
Entries in both direct and indirect maps can be modified at any time.
The new information is used when next uses the map entry to do a mount.
Direct Maps
Entries in a direct map are associated directly with mount points.
Each key is the full path name of an mount point. The direct map as a
whole is not associated with any single directory.
Since each direct map entry results in a new mount, such maps should be
kept short.
If a directory contains direct map mount points, then an in the direc‐
tory will force all the direct map mounts to occur.
Entries in both direct and indirect maps can be modified at any time.
The new information is used when next uses the map entry to do a mount.
New entries added to a master map or direct map will not be useful
until the command is run to install them as new mount points. New
entries added to an indirect map may be used immediately.
Included Maps
The contents of another map can be included within a map with an entry
of the form:
If mapname begins with a slash then it is assumed to be the path name
of a local file. Otherwise the location of the map is determined by
the policy of the name service switch according to the entry for the
automounter in such as
If the name service is then the name is assumed to be that of a local
file in If the key being searched for is not found in the included map,
the search continues with the next entry.
Special Maps
There are two special maps available: and The map is used with the
directory and assumes that the map key is the hostname of an NFS
server. The daemon dynamically constructs a map entry from the
server's list of exported filesystems. References to a directory under
will refer to the corresponding directory relative to root.
The map cancels a map for the directory indicated. This is most useful
in the map for cancelling entries that would otherwise be inherited
from the include entry. To be effective, the entries must be inserted
before the included map entry.
Executable Maps
Local maps that have the execute bit set in their file permissions will
be executed by the automounter and provided with a key to be looked up
as an argument. The executable map is expected to return the content
of an automounter map entry on its standard output or no output if the
entry cannot be determined. A direct map cannot be made executable.
Configuration and the auto_master Map
When initiated without arguments, consults the master map for a list of
mount points and their maps. It mounts any mounts that are not already
mounted, and unmounts mounts that have been removed from the master map
or direct map.
The master map is assumed to be called and its location is determined
by the name service switch policy. Normally the master map is located
initially as a local file,
Browsing
Browsing of indirect maps allows all of the potential mount points to
be visible for that map regardless of whether they are mounted or not.
The option can be added to any indirect map to disable browsing. For
example:
In this case, any host names would only be visible in after they are
mounted. The option enables browsing of file systems. This is the
default for all indirect maps, although it is suggested that the entry
contain the option.
Note that, although a listing of the directory associated with an indi‐
rect map shows all potential mountable entries, the attributes associ‐
ated with those entries are temporary until the actual filesystem
attributes can be retrieved once the filesystem has been mounted.
Network Information Service (NIS) and Yellow Pages (YP)
The Network Information Service (NIS) was formerly known as Sun Yellow
Pages (YP). The functionality of the two remains the same.
RETURN VALUE
returns the following values:
Success.
Failure.
Map not found.
AUTHOR
was developed by Sun Microsystems, Inc.
FILES
Master automount map.
Name service switch configuration file.
command.
SEE ALSOautomountd(1M), cfsadmin(1M), mount(1M).
automount(1M)
