README.amd-maps

amd map parser
==============

The ability to parse amd format maps has been added to autofs.

How to use amd maps in autofs
-----------------------------

To add amd map parsing to autofs a new "format" module has been added.

There are two ways to use this new map format module. First, the existing
master map syntax can be used as described below, and second, sections that
use the top level mount path may be added to the autofs configuration below
the "amd" section in much the same way as is done with amd.

The master map entry syntax is:

mount-point [map-type[,format]:]map [options]

For amd format maps this becomes:

/amd/mp   file,amd:amd.mp

which will use file as the map source and the amd format parser for
the map.

In order to use nsswitch to specify the map source an amd per-mount
section needs to be added to the autofs configuration so autofs
knows the master map entry is an amd format mount.

If an amd-per-mount section is added to the autofs configuration a
corresponding master map entry is optional. If both are present the
map name given in the master map entry will override a "map_name"
option in the amd per-mount section.

If an amd per-mount section is used alone then not giving the "map_type"
option will alow the use of nsswicth for map selection.

See below for an example of an amd per-mount configuration entry.


Configuration sub-system changes
--------------------------------

The configuration sub-system has changed to accommodate the amd parser.
See autofs.conf(5) for more information on format changes.

The configuration is now split into system initialization only
configuration and the daemon configuration. Previously everything was
located in the system initialization configuration file, but now the
configuration is located in autofs.conf in the directory the distribution
uses for the autofs configuration.

There is information about what amd configuration entries can be used
in comments of the installed configuration so that's worth a look.

All that's needed to add an existing amd configuration to autofs is to
add it below the autofs configuration. Apart from changing the amd
"[ global ]" section name to "[ amd ]" nothing else should need to be
changed. However, quite a few amd configuration options don't have
meaning within autofs. When these options are seen they are logged.

Be aware that, if the an old configuration exists and the configuration
hasn't been updated after the installation, changes to the the old
configuration will override changes to the new configuration because
backward compatibility takes priority over the new implementation.

The amd per-mount sections have two functions, to allow per-mount
configuration, as it does in amd, and to allow master map entries to
avoid the need to specify the "type,format" part of the master map
entry. This allows them to use the nsswitch map source functionality
in the same way autofs master map entries do.

If amd per-mount sections are present in the autofs configuration
their corresponding master map entries are optional. This allows
amd maps to be used without adding incompatible entries to the autofs
master map in shared infrastructure environments.

If a section for an amd mount is added below the global amd section
using the mount point path (as is done in amd.conf) then autofs will
know the map format is amd (it doesn't matter if there are no other
configuration options in the mount point section).

If there is a corresponding master map entry the map given in the
master map entry will be used over the map_name option if it is
present in an amd per-mount section.

If a mount point is present in the master map and the source of the
map is nis then it is sufficient to use (for example):

/amd/mp           amd.mp

in the master map and

automount: nis

in /etc/nsswitch.conf or

[ amd ]
map_type = nis

in the configuration along with

[ /amd/mp ]

or

[ /amd/mp ]
map_type = nis

An example of an amd per-mount configuration entry is:

[ amd ]
...

[ /test ]
map_name = /etc/amd.test
#map_type = file
#search_path =			/etc
#browsable_dirs =		yes | no
browsable_dirs =		yes


amd map options that can be used
--------------------------------

In an attempt to describe the usable amd map options, many of the amd
map options have been added to autofs(5).

Not all the amd functionality has been implemented. The autofs(5) man
page usually mentions if something hasn't been implemented so that's
worth checking.

What hasn't been implemented
----------------------------

The configuration options fully_qualified_hosts, unmount_on_exit and
browsable_dirs = full (and a couple of others) aren't implemented.

Map types (sources) ndbm, passwd are not implemented.
The map source "sss" can't be used for amd format maps.

Map caching options aren't used, the existing autofs map caching is
always used for available map sources.

The regex map key matching feature is not implemented.

Mount types lustre, nfsx, jfs, program and direct haven't been
implemented and other mount types that aren't implemented in amd are
also not available.

How to find out more
--------------------

Have a look at the man pages autofs.conf(5), autofs(5) and to a
lesser extent auto.master(5). These may help.

But the best way to get more information is to ask on the
autofs mailing list as described in the README file.

Ian