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

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

       -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

              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 NOTES).

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

ARGUMENTS         top

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

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

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

       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
       2020-11-01.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-08-25.)  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)