1AUTOFS(5) File Formats Manual AUTOFS(5)
2
6 autofs - Format of the automounter maps
7
9 The automounter maps are FILE, NIS, NISPLUS or LDAP maps referred to by
10 the master map of the automounter (see auto.master(5)). These maps
11 describe how file systems below the mount point of the map (given in
12 the master map) are to be mounted. This page describes the sun map
13 format; if another map format, other than amd , is specified (e.g. hes‐
14 iod), this documentation does not apply.
15 Indirect maps, except for the internal hosts map, can be changed on the
17 fly and the automouter will recognize those changes on the next opera‐
18 tion it performs on that map. Direct maps require a HUP signal be sent
19 to the daemon to refresh their contents as does the master map.
20
22 This is a description of the text file format. Other methods of speci‐
23 fying these files may exist. All empty lines or lines beginning with #
24 are ignored. The basic format of one line in such maps is:
25 key [-options] location
27 key
29 For indirect mounts this is the part of the path name between
30 the mount point and the path into the filesystem when it is
31 mounted. Usually you can think about the key as a sub-directory
32 name below the autofs managed mount point.
33 For direct mounts this is the full path of each mount point.
35 This map is always associated with the /- mount point in the
36 master map.
37 options
39 Zero or more options may be given. Options can also be given in
40 the auto.master file in which case both values are cumulative
41 (this is a difference from SunOS). The options are a list of
42 comma separated options as customary for the mount(8) command.
43 There are several special options
45 -fstype=
47 is used to specify a filesystem type if the filesystem is
48 not of the default NFS type. This option is processed by
49 the automounter and not by the mount command.
50 -strict
52 is used to treat errors when mounting file systems as
53 fatal. This is important when multiple file systems
54 should be mounted (`multi-mounts'). If this option is
55 given, no file system is mounted at all if at least one
56 file system can't be mounted.
57 -use-weight-only
59 is used to make the weight the sole factor in selecting a
60 server when multiple servers are present in a map entry.
61 and
62 -no-use-weight-only
64 can be used to negate the option if it is present in the
65 master map entry for the map but is not wanted for the
66 given mount.
67 location
69 The location specifies from where the file system is to be
70 mounted. In the most cases this will be an NFS volume and the
71 usual notation host:pathname is used to indicate the remote
72 filesystem and path to be mounted. If the filesystem to be
73 mounted begins with a / (such as local /dev entries or smbfs
74 shares) a : needs to be prefixed (e.g. :/dev/sda1).
75
77 Indirect map:
78 kernel -ro,soft,intr ftp.kernel.org:/pub/linux
80 boot -fstype=ext2 :/dev/hda1
81 windoze -fstype=smbfs ://windoze/c
82 removable -fstype=ext2 :/dev/hdd
83 cd -fstype=iso9660,ro :/dev/hdc
84 floppy -fstype=auto :/dev/fd0
85 server -rw,hard,intr / -ro myserver.me.org:/ \
86 /usr myserver.me.org:/usr \
87 /home myserver.me.org:/home
88 In the first line we have a NFS remote mount of the kernel directory on
90 ftp.kernel.org. This is mounted read-only. The second line mounts an
91 ext2 volume from a local ide drive. The third makes a share exported
92 from a Windows machine available for automounting. The rest should be
93 fairly self-explanatory. The last entry (the last three lines) is an
94 example of a multi-map (see below).
95 If you use the automounter for a filesystem without access permissions
97 (like vfat), users usually can't write on such a filesystem because it
98 is mounted as user root. You can solve this problem by passing the
99 option gid=<gid>, e.g. gid=floppy. The filesystem is then mounted as
100 group floppy instead of root. Then you can add the users to this group,
101 and they can write to the filesystem. Here's an example entry for an
102 autofs map:
103 floppy-vfat -fstype=vfat,sync,gid=floppy,umask=002 :/dev/fd0
105 Direct map:
107 /nfs/apps/mozilla bogus:/usr/local/moxill
109 /nfs/data/budgets tiger:/usr/local/budgets
110 /tst/sbin bogus:/usr/sbin
111
114 Map Key Substitution
115 An & character in the location is expanded to the value of the key
116 field that matched the line (which probably only makes sense together
117 with a wildcard key).
118 Wildcard Key
120 A map key of * denotes a wild-card entry. This entry is consulted if
121 the specified key does not exist in the map. A typical wild-card entry
122 looks like this:
123 * server:/export/home/&
125 The special character '&' will be replaced by the provided key. So, in
127 the example above, a lookup for the key 'foo' would yield a mount of
128 server:/export/home/foo.
129 Variable Substitution
131 The following special variables will be substituted in the location
132 field of an automounter map entry if prefixed with $ as customary from
133 shell scripts (curly braces can be used to separate the field name):
134 ARCH Architecture (uname -m)
136 CPU Processor Type
137 HOST Hostname (uname -n)
138 OSNAME Operating System (uname -s)
139 OSREL Release of OS (uname -r)
140 OSVERS Version of OS (uname -v)
141 autofs provides additional variables that are set based on the user
143 requesting the mount:
144 USER The user login name
146 UID The user login ID
147 GROUP The user group name
148 GID The user group ID
149 HOME The user home directory
150 SHOST Short hostname (domain part removed if present)
151 If a program map is used these standard environment variables will have
153 a prefix of "AUTOFS_" to prevent interpreted languages like python from
154 being able to load and execute arbitray code from a user home direc‐
155 tory.
156 Additional entries can be defined with the -Dvariable=Value map-option
158 to automount(8).
159 Executable Maps
161 A map can be marked as executable. A program map will be called with
162 the key as an argument. It may return no lines of output if there's an
163 error, or one or more lines containing a map entry (with \ quoting line
164 breaks). The map entry corresponds to what would normally follow a map
165 key.
166 An executable map can return an error code to indicate the failure in
168 addition to no output at all. All output sent to stderr is logged into
169 the system logs.
170 Multiple Mounts
172 A multi-mount map can be used to name multiple filesystems to mount.
173 It takes the form:
174 key [ -options ] [[/] location [/relative-mount-point [ -options ] location...]...
176 This may extend over multiple lines, quoting the line-breaks with `\´.
179 If present, the per-mountpoint mount-options are appended to the
180 default mount-options. This behaviour may be overridden by the
181 append_options configuration setting.
182 Replicated Server
184 A mount location can specify multiple hosts for a location, porten‐
185 tially with a different export path for the same file system. Histori‐
186 cally these different locations are read-only and provide the same
187 replicated file system.
188 Multiple replicated hosts, same path:
190 <path> host1,host2,hostn:/path/path
191 Multiple hosts, some with same path, some with another
193 <path> host1,host2:/blah host3:/some/other/path
194 Multiple replicated hosts, different (potentially) paths:
196 <path> host1:/path/pathA host2:/path/pathB
197 Mutliple weighted, replicated hosts same path:
199 <path> host1(5),host2(6),host3(1):/path/path
200 Multiple weighted, replicated hosts different (potentially) paths:
202 <path> host1(3):/path/pathA host2(5):/path/pathB
203 Anything else is questionable and unsupported, but these variations will also work:
205 <path> host1(3),host:/blah
206
208 This version of the automounter supports direct maps stored in FILE,
209 NIS, NISPLUS and LDAP only.
210
212 This is a description of the text file format. Other methods of speci‐
213 fying mount map entries may be required for different map sources. All
214 empty lines or lines beginning with # are ignored. The basic format of
215 one line in such maps is:
216 key location-list
218 key
220 A key is a path (or a single path component alone) that may end
221 in the wildcard key, "*", or the wildcard key alone and must not
222 begin with the "/" character.
223 location-list
225 Following the key is a mount location-list.
226 A location-list list has the following syntax:
228 location[ location[ ... ]] [|| location[ location[ ... ]]
230 A mount location-list can use the cut operator, ||, to specify loca‐
232 tions that should be tried if none of the locations to the left of it
233 where selected for a mount attempt.
234 A mount location consists of an optional colon seperated list of selec‐
236 tors, followed by a colon seperated list of option:=value pairs.
237 The selectors that may be used return a value or boolean result. Those
239 that return a value may be to used with the comparison operators == and
240 != and those that return a boolean result may be negated with the !.
241 For a location to be selected for a mount attempt all of its selectors
243 must evaluate to true. If a location is selected for a mount attempt
244 and succeeds the lookup is completed and returns success. If the mount
245 attempt fails the proceedure continues with the next location until
246 they have all been tried.
247 In addition some selectors take no argumenets, some one argument and
249 others optionally take two arguments.
250 The selectors that take no arguments are:
252 arch
254 The machine architecture which, if not set in the confu‐
255 gration, is obtained using uname(2).
256 karch
258 The machine kernel architecture which, if not set in the
259 confugration, is obtained using uname(2).
260 os
262 The operating system name, if not set in the confugra‐
263 tion, is obtained using uname(2).
264 osver
266 The operating system version, if not set in the confugra‐
267 tion, is obtained using uname(2).
268 full_os
270 The full operating system name, if not set in the confu‐
271 gration this selector has no value.
272 vendor
274 The operating system vendor name, if not set in the
275 confugration this selector has the value "unknown".
276 byte
278 The endianess of the hardware.
279 cluster
281 The name of the local cluster. It has a value only if it
282 is set in the configuration.
283 autodir
285 The base path under which external mounts are done if
286 they are needed. Most mounts are done in place but some
287 can't be and this is the base path under which those
288 mounts will be done.
289 domain
291 The local domain name. It is set to the value of the con‐
292 figuration option sub_domain. If sub_domain is not given
293 in the configuration it is set to the domain part of the
294 local host name, as given by gethostname(2).
295 host
297 The local host name, without the domain part, as given by
298 gethostname(2).
299 hostd
301 The full host name. If sub_domain is given in the config‐
302 uration this is set to the contatenation of host and
303 sub_domain deperated by a .. If sub_domain is not set in
304 the configuration the value of domain is used instead of
305 sub_domain.
306 uid
308 The numeric value of the uid of the user that first
309 requested the mount. Note this is usual the same as that
310 used by amd but can be different within autofs.
311 gid
313 The numeric value of the gid of the user that first
314 requested the mount. Note this is usual the same as that
315 used by amd but can be different within autofs.
316 key
318 The string value of the key being looked up.
319 map
321 The string value of the map name used to lookup keys.
322 path
324 The string value of the full path to the mount being
325 requested.
326 dollar
328 Evaluates to the string "$".
329 The selectors that take one argument are:
331 in_network(network) , network(network) , netnumber(network) ,
333 wire(network)
334 These selectors are all the same. in_network() is the
335 preferred usage. The network argument is an address
336 (which may include a subnet mask) or network name. The
337 function compares network against each interface and
338 returns true if network belongs to the network the inter‐
339 face is connected to.
340 xhost(hostname)
342 The xhost() selector compares hostname to the ${host} and
343 if it doesn't match it attempts to lookup the cannonical
344 name of hostname and compares it to {host} as well.
345 exists(filename)
347 Returns true if filename exits as determined by lstat(2).
348 true()
350 Evaluates to true, the argument is ignored and may be
351 empty.
352 false()
354 Evaluates to false, the argument is ignored and may be
355 empty.
356 The selectors that take up to two arguments are:
358 netgrp(netgroup[,hostname])
360 The netgrp() selector returns true if hostname is a mem‐
361 ber of the netgroup netgroup. If hostname is not given
362 ${host} is used for the comparison.
363 netgrpd(netgroup[,hostname])
365 The netgrpd()i selector behaves the same as netgrp()
366 except that if hostname is not given ${hostd}, the fully
367 qualified hostname, is used instead of ${host}.
368 The options that may be used are:
370 type
372 This is the mount filesystem type. It can have a value
373 of auto, link, linkx, host, lofs, ext2-4, xfs, nfs, nfsl
374 or cdfs. Other types that are not yet implemented or are
375 not available in autofs are nfsx, lustre, jfs, program,
376 cachefs and direct.
377 maptype
379 The maptype option specifies the type of the map source
380 and can have a value of file, nis, nisplus, exec, ldap or
381 hesiod. Map sources either not yet implemented or not
382 available in autofs are sss, ndbm, passwd and union.
383 fs
385 The option fs is used to specify the local filesystem.
386 The meaning of this option (and whether or not it is
387 used) is dependent on the mount filesystem type.
388 rhost
390 The remote host name for network mount requests.
391 rfs
393 The remote host filesystem path for network mount
394 requests.
395 dev
397 Must resolve to the device file for local device mount
398 requests.
399 sublink
401 The sublink option is used to specify a subdirectory
402 within the mount location to which this entry will point.
403 pref
405 The pref option is used to specify a prefix that is
406 prepended to the lookup key before looking up the map
407 entry key.
408 opts
410 The opts option is used to specify mount options to be
411 used for the mount. If a "-" is given it is ignored.
412 Options that may be used are dependend on the mount
413 filesystem.
414 addopts
416 The addopts option is used to specify additional mount
417 options used in addition to the default mount options for
418 the mount location.
419 remopts
421 The addopts option is used to specify mount options used
422 instead the options given in opts when the mount location
423 is on a remote retwork.
424 A number of options aren't available or aren't yet implemented
426 within autofs, these are:
427 cache
429 The cache option isn't used by autofs. The map entry
430 cache is continually updated and stale entries cleaned on
431 re-load when map changes are detected so these configura‐
432 tion entries are not used. The regex map key matching is
433 not implemented and may not be due to the potential over‐
434 head of the full map scans needed on every key lookup.
435 cachedir
437 The cachefs filesystem is not available on Linux, a dif‐
438 ferent implementation is used for caching network mounted
439 file systems.
440 mount , unmount , umount
442 These options are used by the amd program mount type
443 which is not yet implemented.
444 delay
446 This option is not used by the autofs implementation and
447 is ignored.
448
451 Key Matching
452 The amd parser key matching is unusual.
453 The key string to be looked up is constructed by prepending the prefix,
455 if there is one.
456 The resulting relative path string is matched by first trying the sting
458 itself. If no match is found the last component of the key string is
459 replaced with the wilcard match cahracter ("*") and a wildcard match is
460 attemted. This process continues until a match is found or until the
461 last match, against the wilcard match key alone, fails to match a map
462 entry and the key lookup fails.
463 Macro Usage
465 Macros are used a lot in the autofs amd implementation.
466 Many of the option values are set as macro variables corresponding to
468 the option name during the map entry parse. So they may be used in sub‐
469 sequent option values. Beware though, the order in which option values
470 is not necessarily left to right so you may get unexpected results.
471
473 Example NFS mount map:
474 Assuming we have the autofs master map entry:
476 /test file,amd:/etc/amd.test
478 And the following map in /etc/amd.test:
480 /defaults type:=nfs;rhost:=bilbo
482 apps rfs:=/autofs
483 util rhost:=zeus;rfs:=/work/util
484 local rfs:=/shared;sublink:=local
485 In the first line we have an NFS remote mount of the exported directory
487 /autofs from host bilbo which would be mounted on /test/apps. Next
488 another nfs mount for the exported directory /work/util from host zeus.
489 This would be mounted on /test/util.
490 Finally we have an example of the use of the sublink option. In this
492 case the filesystem bilbo:/shared would be mounted on a path external
493 the automount directory (under the direcory given by configuration
494 option auto_dir) and the path /test/local either symlinked or bind
495 mounted (depending on the setting autofs_use_lofs) to the "local" sub‐
496 directory of the external mount.
497
499 automount(8), auto.master(5), autofs(8), autofs.conf(5), mount(8), aut‐
500 ofs_ldap_auth.conf(5).
501
503 This manual page was written by Christoph Lameter <chris@waterf.org>,
504 for the Debian GNU/Linux system. Edited by H. Peter Avian <hpa@trans‐
505 meta.com>, Jeremy Fitzhardinge <jeremy@goop.org> and Ian Kent
506 <raven@themaw.net>.
507 9 Feb 2014 AUTOFS(5)