AUTOMOUNT(8) | System Manager's Manual | AUTOMOUNT(8) |
automount - manage autofs mount points
automount [options] [master_map]
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.
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.
The path argument corresponds to the automounted path name as specified in the master map.
automount takes one optional argument, the name of the master map to use.
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.
autofs(5), autofs(8), autofs.conf(5), auto.master(5), mount(8), autofs_ldap_auth.conf(5).
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 <autofs@vger.kernel.org>. Visit http://vger.kernel.org/vger-lists.html#autofs for information about the list.
H. Peter Anvin <hpa@transmeta.com> and Ian Kent <raven@themaw.net>.
12 Apr 2006 |