The automounter maps are FILE, NIS, NISPLUS or LDAP maps referred to by
the master map of the automounter (see
auto.master(5)).
These maps describe how file systems below the mount point of the map
(given in the master map) are to be mounted. This page describes the
sun
map format; if another map format is specified (e.g. hesiod),
this documentation does not apply.
Indirect maps can be changed on the fly and the automouter will recognize
those changes on the next operation it performs on that map. Direct maps
require a HUP signal be sent to the daemon to refresh their contents as does
the master map.
FORMAT
This is a description of the text file format. Other methods of specifying
these files may exist. All empty lines or lines beginning with # are
ignored. The basic format of one line in such maps is:
key [-options] location
key
For indirect mounts this is the part of the path name between the mount point
and the path into the filesystem when it is mounted. Usually you can think about the
key as a sub-directory name below the autofs managed mount point.
For direct mounts this is the full path of each mount point. This map is always
associated with the /- mount point in the master map.
options
Zero or more options may be given. Options can also be given in the
auto.master
file in which case both values are cumulative (this is a difference
from SunOS). The options are a list of comma separated options as
customary for the
mount(8)
command. There are two special options
-fstype=
used to specify a filesystem type if the filesystem is not of the default
NFS type. This option is processed by the automounter and not by the mount
command.
-strict
is used to treat errors when mounting file systems as fatal. This is important when
multiple file systems should be mounted (`multi-mounts'). If this option
is given, no file system is mounted at all if at least one file system
can't be mounted.
location
The location specifies from where the file system is to be mounted. In the
most cases this will be an NFS volume and the usual notation
host:pathname
is used to indicate the remote filesystem and path to be mounted. If
the filesystem to be mounted begins with a / (such as local
/dev
entries or smbfs shares) a : needs to be prefixed (e.g.
:/dev/sda1).
In the first line we have a NFS remote mount of the kernel directory on
ftp.kernel.org.
This is mounted read-only. The second line mounts an ext2 volume from a
local ide drive. The third makes a share exported from a Windows
machine available for automounting. The rest should be fairly
self-explanatory. The last entry (the last three lines) is an example
of a multi-map (see below).
If you use the automounter for a filesystem without access permissions
(like vfat), users usually can't write on such a filesystem
because it is mounted as user root.
You can solve this problem by passing the option gid=<gid>,
e.g. gid=floppy. The filesystem is then mounted as group
floppy instead of root. Then you can add the users
to this group, and they can write to the filesystem. Here's an
example entry for an autofs map:
An & character in the
location
is expanded to the value of the
key
field that matched the line (which probably only makes sense together with
a wildcard key).
Wildcard Key
A map key of * denotes a wild-card entry. This entry is consulted
if the specified key does not exist in the map. A typical wild-card
entry looks like this:
* server:i/export/home/&
The special character '&' will be replaced by the provided key. So,
in the example above, a lookup for the key 'foo' would yield a mount
of server:/export/home/foo.
Variable Substitution
The following special variables will be substituted in the key and location
fields of an automounter map if prefixed with $ as customary from shell
scripts (Curly braces can be used to separate the field name):
ARCH Architecture (uname -m)
CPU Processor Type
HOST Hostname (uname -n)
OSNAME Operating System (uname -s)
OSREL Release of OS (uname -r)
OSVERS Version of OS (uname -v)
autofs provides additional variables that are set based on the
user requesting the mount:
USER The user login name
UID The user login ID
GROUP The user group name
GID The user group ID
HOME The user home directory
HOST Hostname (uname -n)
Additional entries can be defined with the -Dvariable=Value map-option to
automount(8).
Executable Maps
A map can be marked as executable. A
program
map will be called with the key as an argument. It may
return no lines of output if there's an error, or one or more lines
containing a map entry (with \ quoting line breaks). The map entry
corresponds to what would normally follow a map key.
An executable map can return an error code to indicate the failure in addition
to no output at all. All output sent to stderr is logged into the system
logs.
Multiple Mounts
A
multi-mount map
can be used to name multiple filesystems to mount. It takes the form:
This may extend over multiple lines, quoting the line-breaks with `\'.
If present, the per-mountpoint mount-options are appended to the
default mount-options.
Replicated Server
Multiple replicated hosts, same path:
<path> host1,host2,hostn:/path/path
Multiple hosts, some with same path, some with another
<path> host1,host2:/blah host3:/some/other/path
Multiple replicated hosts, different (potentially) paths:
<path> host1:/path/pathA host2:/path/pathB
Mutliple weighted, replicated hosts same path:
<path> host1(5),host2(6),host3(1):/path/path
Multiple weighted, replicated hosts different (potentially) paths:
<path> host1(3):/path/pathA host2(5):/path/pathB
Anything else is questionable and unsupported, but these variations will also work:
<path> host1(3),host:/blah
UNSUPPORTED
This version of the automounter supports direct maps stored in FILE, NIS, NISPLUS
and LDAP only.
