System Administration Commands automount(1M)
NAME
automount - install automatic mount points
SYNOPSIS
/usr/sbin/automount [-t duration] [-v]
DESCRIPTION
The automount utility installs autofs mount points and asso-
ciates an automount map with each mount point. It starts the
automountd(1M) daemon if it finds any non-trivial entries in
either local or distributed automount maps and if the daemon
is not already running. The autofs file system monitors
attempts to access directories within it and notifies the
automountd(1M) daemon. The daemon uses the map to locate a
file system, which it then mounts at the point of reference
within the autofs file system. A map can be assigned to an
autofs mount using an entry in the /etc/automaster map or a
direct map.
If the file system is not accessed within an appropriate
interval (10 minutes by default), the automountd daemon
unmounts the file system.
The file /etc/automaster determines the locations of all
autofs mount points. By default, this file contains three
entries:
# Master map for automounter
#
]automaster
/net -hosts -nosuid
/home autohome
The ]automaster entry is a reference to an external NIS or
NIS] master map. If one exists, then its entries are read as
if they occurred in place of the ]automaster entry. The
remaining entries in the master file specify a directory on
which an autofs mount will be made followed by the auto-
mounter map to be associated with it. Optional mount options
may be supplied as an optional third field in the each
entry. These options are used for any entries in the map
that do not specify mount options explicitly. The automount
command is usually run without arguments. It compares the
entries /etc/automaster with the current list of autofs
mounts in /etc/mnttab and adds, removes or updates autofs
mounts to bring the /etc/mnttab up to date with the
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/etc/automaster. At boot time it installs all autofs mounts
from the master map. Subsequently, it may be run to install
autofs mounts for new entries in the master map or the
direct map, or to perform unmounts for entries that have
been removed from these maps.
Automount with Solaris Trusted Extensions
If a system is configured with Solaris Trusted Extensions,
additional processing is performed to facilitate multilevel
home directory access. A list of zones whose labels are dom-
inated by the current zone is generated and default
autohome automount maps are generated if they do not
currently exist. These automount maps are named
autohome, where is the name of each
zone's lower-level zone. An autofs mount of each such
autohome map is then performed, regardless of whether it is
explicitly or implicitly listed in the master map. Instead
of autofs mounting the standard autohome map, the zone uses
an autohome file appended with its own zone name. Each
zone's autohome map is uniquely named so that it can be
maintained and shared by all zones using a common name
server.
By default, the home directories of lower-level zones are
mounted read-only under /zone//export/home when
each zone is booted. The default autohome auto-
mount map specifies that path as the source directory for an
lofs remount onto /zone//home/. For
example, the file autohomepublic, as generated from a
higher level zone would contain:
]autohomepublic
* -fstype=lofs :/zone/public/export/home/&
When a home directory is referenced and the name does not
match any other keys in the autohomepublic map, it will
match this loopback mount specification. If this loopback
match occurs and the name corresponds to a valid user whose
home directory does not exist in the public zone, the direc-
tory is automatically created on behalf of the user.
OPTIONS
The following options are supported:
-t duration Specifies a duration, in seconds, that a file
system is to remain mounted when not in use.
The default is 10 minutes.
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-v Verbose mode. Notifies of autofs mounts,
unmounts, or other non-essential information.
USAGE
Map Entry Format
A simple map entry (mapping) takes the form:
key [ -mount-options ] location ...
where key is the full pathname of the directory to mount
when used in a direct map, or the simple name of a subdirec-
tory 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 speci-
fied in mountnfs(1M), and location takes the form:
host:pathname
host is the name of the host from which to mount the file
system, and pathname is the absolute pathname of the direc-
tory to mount.
Options to other file systems are documented on the other
mount* reference manual pages, for example,
mountcachefs(1M).
Replicated File Systems
Multiple location fields can be specified for replicated NFS
file systems, in which case automount and the kernel will
each try to use that information to increase availability.
If the read-only flag is set in the map entry, automountd
mounts a list of locations that the kernel may use, sorted
by several criteria. Only locations available at mount time
will be mounted, and thus be available to the kernel. When a
server does not respond, the kernel will switch to an alter-
nate server. The sort ordering of automount is used to
determine how the next server is chosen. If the read-only
flag is not set, automount will mount the best single loca-
tion, chosen by the same sort ordering, and new servers will
only be chosen when an unmount has been possible, and a
remount is done. Servers on the same local subnet are given
the strongest preference, and servers on the local net are
given the second strongest preference. Among servers equally
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far away, response times will determine the order if no
weighting factors (see below) are used.
If the list includes server locations using both the NFS
Version 2 Protocol and the NFS Version 3 Protocol, automount
will choose only a subset of the server locations on the
list, so that all entries will be the same protocol. It will
choose servers with the NFS Version 3 Protocol so long as an
NFS Version 2 Protocol server on a local subnet will not be
ignored. See the for additional details.
If each location in the list shares the same pathname then a
single location may be used with a comma-separated list of
hostnames:
hostname,hostname...:pathname
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 are assumed to have
a value of zero (most likely to be selected). Progressively
higher values decrease the chance of being selected. In the
example,
man -ro alpha,bravo,charlie(1),delta(4):/usr/man
hosts alpha and bravo have the highest priority; host delta
has the lowest.
Server proximity takes priority in the selection process. In
the example above, if the server delta is on the same net-
work segment as the client, but the others are on different
network segments, then delta will be selected; the weighting
value is ignored. The weighting has effect only when select-
ing between servers with the same network proximity. The
automounter always selects the localhost over other servers
on the same network segment, regardless of weighting.
In cases where each server has a different export point, the
weighting can still be applied. For example:
man -ro alpha:/usr/man bravo,charlie(1):/usr/share/man
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delta(3):/export/man
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 subsequent 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:
jane sparcserver:/home/&
the & expands to jane.
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 previously matched. For instance, if the
following entry appeared in the indirect map for /config:
* &:/export/config/&
this would allow automatic mounts in /config of any remote
file system whose location could be specified as:
hostname:/export/config/hostname
Note that the wildcard key does not work in conjunction with
the -browse option.
Variable Substitution
Client specific variables can be used within an automount
map. For instance, if $HOST appeared within a map, automount
would expand it to its current value for the client's host
name. Supported variables are:
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ARCH The output of arch The architecture name.
For example, sun4 on a
sun4u machine.
CPU The output of uname -p The processor type.
For example, "sparc"
HOST The output of uname -n The host name.
For example, myhost.
KARCH The output of arch -k or uname -m The kernel architec-
ture name or machine
hardware name. For
example, sun4u.
OSNAME The output of uname -s The OS name.
For example, "SunOS"
OSREL The output of uname -r The OS release name.
For example "5.3"
OSVERS The output of uname -v The OS version.
For example, "beta1.0"
NATISA The output of isainfo -n The native instruction
set architecture for
the system.
For example, "sparcv9"
PLATFORM The output of uname -i The platform name. For
example, SUNW,Sun-
Fire-V240.
If a reference needs to be protected from affixed charac-
ters, you can surround the variable name with curly 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 pathname 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 /src
beta -ro\
/ svr1,svr2:/export/src/beta \
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/1.0 svr1,svr2:/export/src/beta/1.0 \
/1.0/man svr1,svr2:/export/src/beta/1.0/man
All offsets must exist on the server under beta. automount
will automatically mount /src/beta, /src/beta/1.0, and
/src/beta/1.0/man, as needed, from either svr1 or svr2,
whichever host is nearest and responds first.
Other File System Types
The automounter assumes NFS mounts as a default file system
type. Other file system types can be described using the
fstype mount option. Other mount options specific to this
file system type can be combined with the fstype option. The
location field must contain information specific to the file
system type. If the location field begins with a slash, a
colon character must be prepended, for instance, to mount a
CD file system:
cdrom -fstype=hsfs,ro :/dev/sr0
or to perform an autofs mount:
src -fstype=autofs autosrc
Use this procedure only if you are not using Volume Manager.
Mounts using CacheFS are most useful when applied to an
entire map as map defaults. The following entry in the mas-
ter map describes cached home directory mounts. It assumes
the default location of the cache directory, /cache.
/home autohome -fstype =cachefs,backfstype=nfs
See the NOTES section for information on option inheri-
tance.
Indirect Maps
An indirect map allows you to specify mappings for the sub-
directories you wish to mount under the directory indicated
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on the command line. In an indirect map, each key consists
of a simple name that refers to one or more file systems
that are to be mounted as needed.
Direct Maps
Entries in a direct map are associated directly with autofs
mount points. Each key is the full pathname of an autofs
mount point. The direct map as a whole is not associated
with any single directory.
Direct maps are distinguished from indirect maps by the /-
key. For example:
# Master map for automounter
#
]automaster
/net -hosts -nosuid,nobrowse
/home autohome -nobrowse
/- autodirect
Included Maps
The contents of another map can be included within a map
with an entry of the form
]mapname
If mapname begins with a slash, it is assumed to be the
pathname 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
/etc/nsswitch.conf, such as
automount: files nis
If the name service is files, then the name is assumed to be
that of a local file in /etc. 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: -hosts and -null. The
-hosts map is used with the /net directory and assumes that
the map key is the hostname of an NFS server. The automountd
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daemon dynamically constructs a map entry from the server's
list of exported file systems. References to a directory
under /net/hermes will refer to the corresponding directory
relative to hermes root.
The -null map cancels a previous map for the directory indi-
cated. This is most useful in the /etc/automaster for can-
celling entries that would otherwise be inherited from the
]automaster include entry. To be effective, the -null
entries must be inserted before the included map entry.
Executable Maps
Local maps that have the execute bit set in their file per-
missions 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 stdout or no output if the entry cannot be
determined. A direct map cannot be made executable.
Configuration and the automaster Map
When initiated without arguments, automount consults the
master map for a list of autofs mount points and their maps.
It mounts any autofs mounts that are not already mounted,
and unmounts autofs mounts that have been removed from the
master map or direct map.
The master map is assumed to be called automaster and its
location is determined by the name service switch policy.
Normally the master map is located initially as a local file
/etc/automaster.
Browsing
The automount daemon supports browsability of indirect maps.
This allows all of the potential mount points to be visible,
whether or not they are mounted. The -nobrowse option can be
added to any indirect autofs map to disable browsing. For
example:
/net -hosts -nosuid,nobrowse
/home autohome
In this case, any hostnames would only be visible in /net
after they are mounted, but all potential mount points would
be visible under /home. The -browse option enables browsa-
bility of autofs file systems. This is the default for all
indirect maps.
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The -browse option does not work in conjunction with the
wildcard key.
Restricting Mount Maps
Options specified for a map are used as the default options
for all the entries in that map. They are ignored when map
entries specify their own mount options.
In some cases, however, it is desirable to force nosuid,
nodevices, nosetuid, or noexec for a complete mount map and
its submounts. This can be done by specifying the additional
mount option, -restrict.
/home autohome -restrict,nosuid,hard
The -restrict option forces the inheritance of all the res-
trictive options nosuid, nodevices, nosetuid, and noexec as
well as the restrict option itself. In this particular exam-
ple, the nosuid and restrict option are inherited but the
hard option is not. The restrict option also prevents the
execution of "executable maps" and is enforced for auto
mounts established by programs with fewer than all
privileges available in their zone.
EXIT STATUS
The following exit values are returned:
0 Successful completion.
1 An error occurred.
FILES
/etc/automaster Master automount map.
/etc/autohome Map to support automounted home
directories.
/etc/default/autofs Supplies default values for parame-
ters for automount and automountd.
See autofs(4).
/etc/nsswitch.conf Name service switch configuration
file. See nsswitch.conf(4).
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ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWcsu
SEE ALSO
isainfo(1), ls(1), svcs(1), uname(1), automountd(1M),
mount(1M), mountcachefs( 1M), mountnfs(1M), svcadm(1M),
autofs(4), attributes(5), nfssec(5), smf(5)
NOTES
autofs mount points must not be hierarchically related.
automount does not allow an autofs mount point to be created
within another autofs mount.
Since each direct map entry results in a new autofs mount
such maps should be kept short.
Entries in both direct and indirect maps can be modified at
any time. The new information is used when automountd 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 automount command is run to install them as
new autofs mount points. New entries added to an indirect
map may be used immediately.
As of the Solaris 2.6 release, a listing (see ls(1)) of the
autofs directory associated with an indirect map shows all
potential mountable entries. The attributes associated with
the potential mountable entries are temporary. The real file
system attributes will only be shown once the file system
has been mounted.
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. Note that map entities with options override the
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default options, as at this time, the options do not con-
catenate. The concatenation feature is planned for a future
release.
When operating on a map that invokes an NFS mount, the
default number of retries for the automounter is 0, that is,
a single mount attempt, with no retries. Note that this is
significantly different from the default (10000) for the
mountnfs(1M) utility.
The Network Information Service (NIS) was formerly known as
Sun Yellow Pages (YP). The functionality of the two remains
the same.
The automount service is managed by the service management
facility, smf(5), under the service identifier:
svc:/system/filesystem/autofs:default
Administrative actions on this service, such as enabling,
disabling, or requesting restart, can be performed using
svcadm(1M). The service's status can be queried using the
svcs(1) command.
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