automount(8) — Linux manual page


AUTOMOUNT(8)             System Manager's Manual            AUTOMOUNT(8)

NAME         top

       automount - manage autofs mount points

SYNOPSIS         top

       automount [options] [master_map]

DESCRIPTION         top

       The automount program is used to manage mount points for autofs,
       the inlined Linux automounter.  automount works by reading the
       auto.master(5) map and sets up mount points for each entry in the
       master map allowing them to be automatically mounted when
       accessed. The file systems are then automatically umounted after
       a period of inactivity.

OPTIONS         top

       -h, --help
              Print brief help on program usage.

       -p, --pid-file
              Write the pid of the daemon to the specified file.

       -t <seconds>, --timeout <seconds>
              Set the global minimum timeout, in seconds, until
              directories are unmounted. The default is 10 minutes.
              Setting the timeout to zero disables umounts completely.
              The internal program default is 10 minutes, but the
              default installed configuration overrides this and sets
              the timeout to 5 minutes to be consistent with earlier
              autofs releases.

       -M <seconds>, --master-wait <seconds>
              Set the maximum time to wait for the master map to become
              available if it cannot be read at program start.

       -n <seconds>, --negative-timeout <seconds>
              Set the default timeout for caching failed key lookups.
              The default is 60 seconds.

       -v, --verbose
              Enables logging of general status and progress messages
              for all autofs managed mounts.

       -d, --debug
              Enables logging of general status and progress messages as
              well as debugging messages for all autofs managed mounts.

       -Dvariable=value, --define variable=value
              Define a global macro substitution variable. Global
              definitions are over-ridden macro definitions of the same
              name specified in mount entries.

       -S, --systemd-service
              Used when running the automounter as a systemd service to
              ensure log entry format is consistent with the log entry
              format when running as a daemon.

       -f, --foreground
              Run the daemon in the foreground and log to stderr instead
              of syslog."

       -r, --random-multimount-selection
              Enables the use of random selection when choosing a host
              from a list of replicated servers.

       -m, --dumpmaps [<map type> <map name>]
              With no parameters, list information about the configured
              automounter maps, then exit.

              If the dumpmaps option is given and is followed by two
              parameters, "<map type> <map name>" then simple "<key,
              value>" pairs that would be read in by a map read are
              printed to stdout if the given map type and map name are
              found in the map configuration.

              If the map is an LDAP map and there is more than one map
              of same name in different base dns only the first map
              encountered by autofs will be listed. Similarly, if the
              map is a file map and there is more than one map of the
              same name in different directories, only the first map
              encountered will be listed.

              If the map type is an old style multi-map and any one of
              the map names in the multi-map entry matches the given map
              name the entries that would be used by autofs for the
              whole multi-map will be listed.

       -O, --global-options
              Allows the specification of global mount options used for
              all master map entries. These options will either replace
              or be appended to options given in a master map entry
              depending on the APPEND_OPTIONS configuration setting.

       -V, --version
              Display the version number, then exit.

       -l, --set-log-priority priority path [path,...]
              Set the daemon log priority to the specified value.  Valid
              values include the numbers 0-7, or the strings emerg,
              alert, crit, err, warning, notice, info, or debug. Log
              level debug will log everything, log levels info, warn (or
              warning), or notice with enable the daemon verbose
              logging. Any other level will set basic logging. Note that
              enabling debug or verbose logging in the autofs global
              configuration will override dynamic log level changes. For
              example, if verbose logging is set in the configuration
              then attempting to set logging to basic logging, by using
              alert, crit, err or emerg won't stop the verbose logging.
              However, setting logging to debug will lead to everything
              (debug logging) being logged witch can then also be
              disabled, returning the daemon to verbose logging. This
              option can be specified to change the logging priority of
              an already running automount process.

              The path argument corresponds to the automounted path name
              as specified in the master map.

       -C, --dont-check-daemon
              Don't check if the daemon is currently running (see

       -F, --force
              Force an unlink umount of existing mounts under configured
              autofs managed mount points during startup. This can cause
              problems for processes with working directories within
              these mounts (see NOTES).

       -U, --force-exit
              Force an unlink umount of existing mounts under configured
              autofs managed mount points and exit rather than
              continuing the startup. This can cause problems for
              processes with working directories within these mounts
              (see NOTES).

ARGUMENTS         top

       automount takes one optional argument, the name of the master map
       to use.

              Location for autofs master map that defines autofs managed
              mount points and the mount maps they will use. The default
              is auto.master.

NOTES         top

       If the automount daemon catches a USR1 signal, it will umount all
       currently unused autofs managed mounted file systems and continue
       running (forced expire).  If it catches the TERM signal it will
       umount all unused autofs managed mounted file systems and exit if
       there are no remaining busy file systems. If autofs has been
       compiled with the option to ignore busy mounts on exit it will
       exit leaving any busy mounts in place otherwise busy file systems
       will not be umounted and autofs will not exit.  Alternatively, if
       autofs has been compiled with the option to enable forced
       shutdown then a USR2 signal to the daemon will cause all mounts
       to be umounted and any busy mounts to be forcibly umounted,
       including autofs mount point directories (summary execution).
       Note that the forced umount is an unlink operation and the actual
       umount will not happen in the kernel until active file handles
       are released.  The daemon also responds to a HUP signal which
       triggers an update of the maps for each mount point.

       If any autofs mount point directories are busy when the daemon is
       sent an exit signal the daemon will not exit. The exception to
       this is if autofs has been built with configure options to either
       ignore busy mounts at exit or force umount at exit. If the ignore
       busy mounts at exit option is used the filesystems will be left
       in a catatonic (non-functional) state and can be manually
       umounted when they become unused. If the force umount at exit
       option is used the filesystems will be umounted but the mount
       will not be released by the kernel until they are no longer in
       use by the processes that held them busy.  If automount managed
       filesystems are found mounted when autofs is started they will be
       recovered unless they are no longer present in the map in which
       case they need to umounted manually.

       If the option to disable the check to see if the daemon is
       already running is used be aware that autofs currently may not
       function correctly for certain types of automount maps. The
       mounts of the separate daemons might interfere with one another.
       The implications of running multiple daemon instances needs to be
       checked and tested before we can say this is supported.

       If the option to force an unlink of mounts at startup is used
       then processes whose working directory is within unlinked
       automounted directories will not get the correct pwd from the
       system. This is because, after the mount is unlinked from the
       mount tree, anything that needs to walk back up the mount tree to
       construct a path, such as getcwd(2) and the proc filesystem
       /proc/<pid>/cwd, cannot work because the point from which the
       path is constructed has been detached from the mount tree.

SEE ALSO         top

       autofs(5), autofs(8), autofs.conf(5), auto.master(5), mount(8),

BUGS         top

       Don't know, I've fixed everything I know about.

       The documentation could be better.

       Please report other bugs along with a detailed description to
       <>. Visit for information
       about the list.

AUTHOR         top

       H. Peter Anvin <> and Ian Kent

COLOPHON         top

       This page is part of the autofs (automount) project.  Information
       about the project can be found at ⟨⟩.  If
       you have a bug report for this manual page, send it to  This page was obtained from the
       project's upstream Git repository
       ⟨git://⟩ on
       2021-08-27.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-07-07.)  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

                               12 Apr 2006                  AUTOMOUNT(8)

Pages that refer to this page: autofs(5)autofs.conf(5)auto.master(5)nfs(5)systemd.automount(5)autofs(8)