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6 Amd Configuration File

The `amd.conf' file is the configuration file for Amd, as part of the am-utils suite. This file contains runtime configuration information for the Amd automounter program.

6.1 File Format

The `amd.conf' file consists of sections and parameters. A section begins with the name of the section in square brackets `[]' and continues until the next section begins or the end of the file is reached. Sections contain parameters of the form `name = value'.

The file is line-based -- that is, each newline-terminated line represents either a comment, a section name or a parameter. No line-continuation syntax is available.

Section names, parameter names and their values are case sensitive.

Only the first equals sign in a parameter is significant. Whitespace before or after the first equals sign is discarded. Leading, trailing and internal whitespace in section and parameter names is irrelevant. Leading and trailing whitespace in a parameter value is discarded. Internal whitespace within a parameter value is not allowed, unless the whole parameter value is quoted with double quotes as in `name = "some value"'.

Any line beginning with a pound sign `#' is ignored, as are lines containing only whitespace.

The values following the equals sign in parameters are all either a string (no quotes needed if string does not include spaces) or a boolean, which may be given as `yes'/`no'. Case is significant in all values. Some items such as cache timeouts are numeric.

6.2 The Global Section

The global section must be specified as `[global]'. Parameters in this section either apply to Amd as a whole, or to all other regular map sections which follow. There should be only one global section defined in one configuration file.

It is highly recommended that this section be specified first in the configuration file. If it is not, then regular map sections which precede it will not use global values defined later.

6.3 Regular Map Sections

Parameters in regular (non-global) sections apply to a single map entry. For example, if the map section `[/homes]' is defined, then all parameters following it will be applied to the `/homes' Amd-managed mount point.

6.4 Common Parameters

These parameters can be specified either in the global or a map-specific section. Entries specified in a map-specific section override the default value or one defined in the global section. If such a common parameter is specified only in the global section, it is applicable to all regular map sections that follow.

6.4.1 browsable_dirs Parameter

(type=string, default=`no'). If `yes', then Amd's top-level mount points will be browsable to readdir(3) calls. This means you could run for example ls(1) and see what keys are available to mount in that directory. Not all entries are made visible to readdir(3): the `/defaults' entry, wildcard entries, and those with a `/' in them are not included. If you specify `full' to this option, all but the `/defaults' entry will be visible. Note that if you run a command which will attempt to stat(2) the entries, such as often done by `ls -l' or `ls -F', Amd will attempt to mount every entry in that map. This is often called a "mount storm".

6.4.2 map_options Parameter

(type=string, default no options). This option is the same as specifying map options on the command line to Amd, such as `cache:=all'.

6.4.3 map_type Parameter

(type=string, default search all map types). If specified, Amd will initialize the map only for the type given. This is useful to avoid the default map search type used by Amd which takes longer and can have undesired side-effects such as initializing NIS even if not used. Possible values are

`file'
plain files
`hesiod'
Hesiod name service from MIT
`ldap'
Lightweight Directory Access Protocol
`ndbm'
(New) dbm style hash files
`nis'
Network Information Services (version 2)
`nisplus'
Network Information Services Plus (version 3)
`passwd'
local password files
`union'
union maps

6.4.4 mount_type Parameter

(type=string, default=`nfs'). All Amd mount types default to NFS. That is, Amd is an NFS server on the map mount points, for the local host it is running on. If `autofs' is specified, Amd will be an autofs server for those mount points.

6.4.5 search_path Parameter

(type=string, default no search path). This provides a (colon-delimited) search path for file maps. Using a search path, sites can allow for local map customizations and overrides, and can distributed maps in several locations as needed.

6.5 Global Parameters

The following parameters are applicable to the `[global]' section only.

6.5.1 arch Parameter

(type=string, default to compiled in value). Allows you to override the value of the arch Amd variable.

6.5.2 auto_dir Parameter

(type=string, default=`/a'). Same as the -a option to Amd. This sets the private directory where Amd will create sub-directories for its real mount points.

6.5.3 cache_duration Parameter

(type=numeric, default=300). Same as the -c option to Amd. Sets the duration in seconds that looked up map entries remain in the cache.

6.5.4 cluster Parameter

(type=string, default no cluster). Same as the -C option to Amd. Specifies the alternate HP-UX cluster to use.

6.5.5 debug_options Parameter

(type=string, default no debug options). Same as the -D option to Amd. Specify any debugging options for Amd. Works only if am-utils was configured for debugging using the --enable-debug option. The `mem' option alone can be turned on via --enable-debug=mem. Otherwise debugging options are ignored. Options are comma delimited, and can be preceded by the string `no' to negate their meaning. You can get the list of supported debugging options by running amd -v. Possible values are:

`all'
all options
`amq'
register for amq
`daemon'
enter daemon mode
`fork'
fork server
`full'
program trace
`mem'
trace memory allocations
`mtab'
use local `./mtab' file
`str'
debug string munging
`test'
full debug but no daemon
`trace'
protocol trace

6.5.6 dismount_interval Parameter

(type=numeric, default=120). Same as the -w option to Amd. Specify in seconds, the time between attempts to dismount file systems that have exceeded their cached times.

6.5.7 fully_qualified_hosts Parameter

(type=string, default=`no'). If `yes', Amd will perform RPC authentication using fully-qualified host names. This is necessary for some systems, and especially when performing cross-domain mounting. For this function to work, the Amd variable `${hostd}' is used, requiring that `${domain}' not be null.

6.5.8 hesiod_base Parameter

(type=string, default=`automount'). Specify the base name for hesiod maps.

6.5.9 karch Parameter

(type=string, default to karch of the system). Same as the -k option to Amd. Allows you to override the kernel-architecture of your system. Useful for example on Sun (Sparc) machines, where you can build one Amd binary, and run it on multiple machines, yet you want each one to get the correct karch variable set (for example, sun4c, sun4m, sun4u, etc.) Note that if not specified, Amd will use uname(2) to figure out the kernel architecture of the machine.

6.5.10 ldap_base Parameter

(type=string, default not set). Specify the base name for LDAP.

6.5.11 ldap_cache_maxmem Parameter

(type=numeric, default=131072). Specify the maximum memory Amd should use to cache LDAP entries.

6.5.12 ldap_cache_seconds Parameter

(type=numeric, default=0). Specify the number of seconds to keep entries in the cache.

6.5.13 ldap_hostports Parameter

(type=string, default not set). Specify LDAP-specific values such as country and organization.

6.5.14 local_domain Parameter

(type=string, default no sub-domain). Same as the -d option to Amd. Specify the local domain name. If this option is not given the domain name is determined from the hostname, by removing the first component of the fully-qualified host name.

6.5.15 log_file Parameter

(type=string, default=`stderr'). Same as the -l option to Amd. Specify a file name to log Amd events to. If the string `/dev/stderr' is specified, Amd will send its events to the standard error file descriptor.

If the string `syslog' is given, Amd will record its events with the system logger syslogd(8). If your system supports syslog facilities, then the default facility used is `LOG_DAEMON'.

When using syslog, if you wish to change the facility, append its name to the option name, delimited by a single colon. For example, if it is the string `syslog:local7' then Amd will log messages via syslog(3) using the `LOG_LOCAL7' facility. If the facility name specified is not recognized, Amd will default to `LOG_DAEMON'. Note: while you can use any syslog facility available on your system, it is generally a bad idea to use those reserved for other services such as `kern', `lpr', `cron', etc.

6.5.16 log_options Parameter

(type=string, default no logging options). Same as the -x option to Amd. Specify any logging options for Amd. Options are comma delimited, and can be preceded by the string `no' to negate their meaning. The `debug' logging option is only available if am-utils was configured with --enable-debug. You can get the list of supported debugging options by running amd -v. Possible values are:

`all'
all messages
`debug'
debug messages
`error'
non-fatal system errors
`fatal'
fatal errors
`info'
information
`map'
map errors
`stats'
additional statistical information
`user'
non-fatal user errors
`warn'
warnings
`warning'
warnings

6.5.17 nfs_retransmit_counter Parameter

(type=numeric, default=110). Same as the counter part of the -t interval.counter option to Amd. Specifies the retransmit counter's value in tenths of seconds.

6.5.18 nfs_retry_interval Parameter

(type=numeric, default=8). Same as the interval part of the -t interval.counter option to Amd. Specifies the interval in tenths of seconds, between NFS/RPC/UDP retries.

6.5.19 nis_domain Parameter

(type=string, default to local NIS domain name). Same as the -y option to Amd. Specify an alternative NIS domain from which to fetch the NIS maps. The default is the system domain name. This option is ignored if NIS support is not available.

6.5.20 normalize_hostnames Parameter

(type=boolean, default=`no'). Same as the -n option to Amd. If `yes', then the name referred to by ${rhost} is normalized relative to the host database before being used. The effect is to translate aliases into "official" names.

6.5.21 os Parameter

(type=string, default to compiled in value). Same as the -O option to Amd. Allows you to override the compiled-in name of the operating system. Useful when the built-in name is not desired for backward compatibility reasons. For example, if the built-in name is `sunos5', you can override it to `sos5', and use older maps which were written with the latter in mind.

6.5.22 osver Parameter

(type=string, default to compiled in value). Same as the -o option to Amd. Allows you to override the compiled-in version number of the operating system. Useful when the built-in version is not desired for backward compatibility reasons. For example, if the build in version is `2.5.1', you can override it to `5.5.1', and use older maps that were written with the latter in mind.

6.5.23 pid_file Parameter

(type=string, default=`/dev/stdout'). Specify a file to store the process ID of the running daemon into. If not specified, Amd will print its process id onto the standard output. Useful for killing Amd after it had run. Note that the PID of a running Amd can also be retrieved via Amq (see section 7.4.7 Amq -p option).

This file is used only if the `print_pid' option is on (see section 6.5.26 print_pid Parameter).

6.5.24 plock Parameter

(type=boolean, default=`yes'). Same as the -S option to Amd. If `yes', lock the running executable pages of Amd into memory. To improve Amd's performance, systems that support the plock(3) call can lock the Amd process into memory. This way there is less chance the operating system will schedule, page out, and swap the Amd process as needed. This improves Amd's performance, at the cost of reserving the memory used by the Amd process (making it unavailable for other processes).

6.5.25 portmap_program Parameter

(type=numeric, default=300019). Specify an alternate Port-mapper RPC program number, other than the official number. This is useful when running multiple Amd processes. For example, you can run another Amd in "test" mode, without affecting the primary Amd process in any way. For safety reasons, the alternate program numbers that can be specified must be in the range 300019-300029, inclusive. Amq has an option -P which can be used to specify an alternate program number of an Amd to contact. In this way, amq can fully control any number of Amd processes running on the same host.

6.5.26 print_pid Parameter

(type=boolean, default=`no'). Same as the -p option to Amd. If `yes', Amd will print its process ID upon starting.

6.5.27 print_version Parameter

(type=boolean, default=`no'). Same as the -v option to Amd, but the version prints and Amd continues to run. If `yes', Amd will print its version information string, which includes some configuration and compilation values.

6.5.28 restart_mounts Parameter

(type=boolean, default=`no'). Same as the -r option to Amd. If `yes' Amd will scan the mount table to determine which file systems are currently mounted. Whenever one of these would have been auto-mounted, Amd inherits it.

6.5.29 selectors_on_default Parameter

(type=boolean, default=`no'). If `yes', then the `/defaults' entry of maps will be looked for and any selectors processed before setting defaults for all other keys in that map. Useful when you want to set different options for a complete map based on some parameters. For example, you may want to better the NFS performance over slow slip-based networks as follows:

/defaults \
    wire==slip-net;opts:=intr,rsize=1024,wsize=1024 \
    wire!=slip-net;opts:=intr,rsize=8192,wsize=8192

6.5.30 show_statfs_entries Parameter

(type=boolean), default=`no'). If `yes', then all maps which are browsable will also show the number of entries (keys) they have when df(1) runs. (This is accomplished by returning non-zero values to the statfs(2) system call).

6.5.31 unmount_on_exit Parameter

(type=boolean), default=`no'). If `yes', then Amd will attempt to unmount all file systems which it knows about. Normally it leaves all (esp. NFS) mounted file systems intact. Note that Amd does not know about file systems mounted before it starts up, unless the `restart_mounts' option is used (see section 6.5.28 restart_mounts Parameter).

6.6 Regular Map Parameters

The following parameters are applicable only to regular map sections.

6.6.1 map_name Parameter

(type=string, must be specified). Name of the map where the keys are located.

6.6.2 tag Parameter

(type=string, default no tag). Each map entry in the configuration file can be tagged. If no tag is specified, that map section will always be processed by Amd. If it is specified, then Amd will process the map if the -T option was given to Amd, and the value given to that command-line option matches that in the map section.

6.7 amd.conf Examples

The following is the actual amd.conf file I use at the Computer Science Department of Columbia University.

# GLOBAL OPTIONS SECTION
[ global ]
normalize_hostnames =    no
print_pid =              no
#pid_file =              /var/run/amd.pid
restart_mounts =         yes
#unmount_on_exit =       yes
auto_dir =               /n
log_file =               /var/log/amd
log_options =            all
#debug_options =         all
plock =                  no
selectors_on_default =   yes
# config.guess picks up "sunos5" and I don't want to edit my maps yet
os =                     sos5
# if you print_version after setting up "os", it will show it.
print_version =          no
map_type =               file
search_path =            /etc/amdmaps:/usr/lib/amd:/usr/local/AMD/lib
browsable_dirs =         yes
fully_qualified_hosts =  no

# DEFINE AN AMD MOUNT POINT
[ /u ]
map_name =               amd.u
                         
[ /proj ]                
map_name =               amd.proj
                         
[ /src ]                 
map_name =               amd.src
                         
[ /misc ]                
map_name =               amd.misc
                         
[ /import ]              
map_name =               amd.import
                         
[ /tftpboot/.amd ]       
tag =                    tftpboot
map_name =               amd.tftpboot


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