MAN page from Mandriva 2009 am-utils-6.1.5-5.1mdv2009.0.i586.rpm


Section: File Formats (5)
Updated: 7 August 1997


amd.conf - Amd configuration file 




Theamd.conffile is the configuration file for Amd, as part of the am-utils suite.amd.confcontains runtime configuration information for theAmdautomounter program. 


The file consists of sections and parameters. A section begins with thename of the section in square brackets and continues until the next sectionbegins or the end the file is reached. Sections contain parameters of theform 'name = value'.The file is line-based - that is, each newline-terminated line representseither a comment, a section name or a parameter. No line-continuationsyntax is available.Section, parameter names and their values are case sensitive.Only the first equals sign in a parameter is significant. Whitespace beforeor after the first equals sign is discarded. Leading, trailing andinternal whitespace in section and parameter names is irrelevant. Leadingand trailing whitespace in a parameter value is discarded. Internalwhitespace within a parameter value is not allowed, unless the wholeparameter value is quoted with double quotes as in 'name = "some value"'.Any line beginning with a pound sign (#) is ignored, as are lines containingonly 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 maybe given as yes/no. Case is significant in all values. Some items such ascache timeouts are numeric. 



The [global] section

Parameters in this section either apply to Amd as a whole, or to all otherregular map sections which follow. There should be only one global sectiondefined in one configuration file.It is highly recommended that this section be specified first in theconfiguration file. If it is not, then regular map sections which precedeit will not use global values defined later.


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/homesAmd-managed mount point. 



Parameters common to all sections

These parameters can be specified either in the global or a map specificsection. Entries specified in a map-specific section override the defaultvalue or one defined in the global section. If such a common parameter isspecified only in the global section, it is applicable to all regular mapsections that follow.
browsable_dirs (string, default=no)
If "yes," then Amd's top-level mount points will be browsable toreaddir(3)calls. This means you could run for examplels(1)and see what keys are available to mount in that directory. Not all entriesare made visible to readdir(3): the "/default" entry, wildcardentries, and those with a "/" in them are not included. If you specify"full" to this option, all but "/default" will be visible.Note that if you run a command which will attempt tostat(2)the entries, such as often done by "ls -l" or "ls -F," Amd will attempt tomounteveryentry in that map. This is often called a ``mount storm.''

map_defaults (string, default to empty)
This option sets a string to be used as the map's /defaults entry,overriding any /defaults specified in the map. This allows local users tooverride map defaults without modifying maps globally.

map_options (string, default no options)
This option is the same as specifying map options on the command line toAmd, such as "cache:=all".

map_type (string, default search all map types)
If specified, Amd will initialize the map only for the type given. This isuseful to avoid the default map search type used by Amd which takes longerand can have undesired side-effects such as initializing NIS even if notused. Possible values are

exec      executable mapsfile      plain fileshesiod    Hesiod name service from MITldap      Lightweight Directory Access Protocolndbm      (New) dbm style hash filesnis       Network Information Services (version 2)nisplus   Network Information Services Plus (version 3)passwd    local password filesunion     union maps

mount_type (string, default=nfs)
All Amd mount types default to NFS. That is, Amd is an NFS server on themap mount points, for the local host it is running on. If "autofs" isspecified, Amd will be an autofs server for those mount points.

autofs_use_lofs (string, default=yes)
When set to "yes" and using Autofs, Amd will use lofs-type (loopback) mountsfor type:=link mounts. This has the advantage of mounting in place, andusers get to the see the same pathname that they chdir'ed into. If thisoption is set to "no," then Amd will use symlinks instead: that code is moretested, but negates autofs's big advantage of in-place mounts.

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

selectors_in_defaults (boolean, default=no)
If "yes," then the /defaults entry of maps will search for and process anyselectors before setting defaults for all other keys in that map. Usefulwhen you want to set different options for a complete map based on someparameters. For example, you may want to better the NFS performance overslow slip-based networks as follows:

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

Deprecated form: selectors_on_default


Parameters applicable to the global section only

arch (string, default to compiled in value)
Same as the-Aoption to Amd. Allows you to override the value of thearchAmd variable.

auto_attrcache (numeric, default=0)
Specify in seconds (or units of 0.1 seconds, depending on the OS), what isthe (kernel-side) NFS attribute cache timeout for @i{Amd}'s own automountpoints. A value of 0 is supposed to turn off attribute caching, meaningthat @i{Amd} will be consulted via a kernel-RPC each time someone stat()'sthe mount point (which could be abused as a denial-of-service attack).Warning: some OSs are incapable of turning off the NFS attribute cachereliably. On such systems, Amd may not work reliably under heavy load. Seethe README.attrcache document in the Am-utils distribution for more details.

auto_dir (string, default=/a)
Same as the-aoption to Amd. This sets the private directory where Amd will createsub-directories for its real mount points.

cache_duration (numeric, default=300)
Same as the-coption to Amd. Sets the duration in seconds that looked-up or mounted mapentries remain in the cache.

cluster (string, default no cluster)
Same as the-Coption to Amd. Specifies the alternate HP-UX cluster to use.

debug_mtab_file (string, default=/tmp/mnttab)
Path to mtab file that is used by Amd to store a list of mountedfile systems during debug-mtab mode. This option only appliesto systems that store mtab information on disk.
debug_options (string, default no debug options)
Same as the-Doption to Amd. Specify any debugging options for Amd. Works only ifam-utils was configured for debugging using the --enable-debug option. The"mem" option, as well as all other options, can be turned on via--enable-debug=mem. Otherwise debugging options are ignored. Options arecomma delimited, and can be preceded by the string "no" to negate theirmeaning. You can get the list of supported debugging options by running Amd-H. Possible values are:

all       all optionsamq       register for amqdaemon    enter daemon modefork      fork serverfull      program tracehrtime    print high resolution time stamps (only if syslog(3) is not used)info      info service specific debugging (hesiod, nis, etc.)mem       trace memory allocationsmtab      use local "./mtab" filereaddir   show browsable_dirs progressstr       debug string mungingtest      full debug but no daemontrace     trace protocol and NFS mount argumentsxdrtrace  trace XDR routines

dismount_interval (numeric, default=120)
Same as the-woption to Amd. Specify in seconds, the time between attempts to dismountfile systems that have exceeded their cached times.

domain_strip (boolean, default=yes)
If "yes," then the domainname part referred to by ${rhost} is stripped off. This isuseful to keep logs and smaller. If "no," then the domain namepart is left changed. This is useful when using multiple domains withthe same maps (as you may have hosts whose domain-stripped name isidentical).

exec_map_timeout (numeric, default=10)
The timeout in seconds thatAmdwill wait for an executable map program before an answer is returned fromthat program (or script). This value should be set to as small as possiblewhile still allowing normal replies to be returned before the timer expires,because during the time that the executable map program is queried,Amdis essentially waiting and is thus not responding to any other queries.

forced_unmounts (boolean, default=no)
If set to "yes," and the client OS supports forced or lazy unmounts, thenAmdwill attempt to use them if it gets any of three serious error conditionswhen trying to unmount an existing mount point or mount on top of one: EIO,ESTALE, or EBUSY.

This could be useful to recover from serious conditions such as hardwarefailure of mounted disks, or NFS servers which are down permanently, weremigrated, or changed their IP address. Only "type:=toplvl" mounts hung withEBUSY are forcibly unmounted using this option, which is useful to recoverfrom a hungAmd).

full_os (string, default to compiled in value)
The full name of the operating system, along with its version. Allows youto override the compiled-in full name and version of the operating system.Useful when the compiled-in name is not desired. For example, the fulloperating system name on linux comes up as ``linux'', but you can overrideit to ``linux-2.2.5.''

fully_qualified_hosts (string, default=no)
If "yes,"Amdwill perform RPC authentication using fully-qualified host names. This isnecessary for some systems, and especially when performing cross-domainmounting. For this function to work, theAmdvariable ${hostd} is used, requiring that ${domain} not be null.

hesiod_base (string, default=automount)
Specify the base name for hesiod maps.

karch (string, default to karch of the system)
Same as the-koption to Amd. Allows you to override the kernel-architecture of yoursystem. Useful for example on Sun (Sparc) machines, where you can build oneAmd binary, and run it on multiple machines, yet you want each one to getthe correctkarchvariable set (for example, sun4c, sun4m, sun4u, etc.) Note that if notspecified, Amd will use uname(3) to figure out the kernel architecture ofthe machine.

ldap_base (string, default not set)
Specify the base name for LDAP. This often includes LDAP-specificvalues such as country and organization.

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

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

ldap_hostports (string, default not set)
Specify the LDAP host and port values.

ldap_proto_version (numeric, default=2)
Specify the version of the LDAP protocol to use.

local_domain (string, default no sub-domain)
Same as the-doption to Amd. Specify the local domain name. If this option is not giventhe domain name is determined from the hostname, by removing the firstcomponent of the fully-qualified host name.

localhost_address (string, default to localhost or
Specify the name or IP address for Amd to use when connecting the socketsfor the local NFS server and the RPC server. This defaults to orwhatever the host reports as its local address. This parameter is useful onhosts with multiple addresses where you want to force Amd to connect to aspecific address.

log_file (string, default=/dev/stderr)
Same as the-loption to Amd. Specify a file name to log Amd events to.If the string/dev/stderris specified, Amd will send its events to the standard error file descriptor.If the stringsyslogis given, Amd will record its events with the system loggersyslogd(8).The default syslog facility used is LOG_DAEMON. If youwish to change it, append its name to the log file name, delimited by asingle colon. For example, iflogfileis the stringsyslog:local7then Amd will log messages viasyslog(3)using the LOG_LOCAL7 facility (if it exists on the system).

log_options (string, default no logging options)
Same as the-xoption to Amd. Specify any logging options for Amd. Options are commadelimited, 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 and loggingoptions by runningamd-H.Possible values are:

all       all messagesdebug     debug messageserror     non-fatal system errorsfatal     fatal errorsinfo      informationmap       map errorsstats     additional statistical informationuser      non-fatal user errorswarn      warningswarning   warnings

map_reload_interval (numeric, default=3600)
The number of seconds that Amd will wait before it checks to see if any mapshave changed at their source (NIS servers, LDAP servers, files, etc.). Amdwill reload only those maps that have changed.

nfs_allow_any_interface (string, default=no)
Normally Amd accepts local NFS packets only from If thisparameter is set to "yes" then Amd will accept local NFS packets from anylocal interface; this is useful on hosts that may have multiple interfaceswhere the system is forced to send all outgoing packets (even those bound tothe same host) via an address other than

nfs_allow_insecure_port (string, default=no)
Normally Amd will refuse requests coming from unprivileged ports (i.e.ports >= 1024 on Unix systems), so that only privileged users and the kernelcan send NFS requests to it. However, some kernels (certain versions ofDarwin, MacOS X, and Linux) have bugs that cause them to use unprivilegedports in certain situations, which causes Amd to stop dead in its tracks.This parameter allows Amd to operate normally even on such systems, at theexpense of a slight decrease in the security of its operations. If you seemessages like "ignoring request from foo:1234, port not reserved" in yourAmd log, try enabling this parameter and give it another go.

nfs_proto (string, default to trying version tcp then udp)
By default, Amd tries TCP and then UDP. This option forces the overall NFSprotocol used to TCP or UDP. It overrides what is in the Amd maps, and isuseful when Amd is compiled with NFSv3 support that may not be stable. Withthis option you can turn off the complete usage of NFSv3 dynamically(without having to recompile Amd) until such time as NFSv3 support isdesired again.

nfs_retransmit_counter (numeric, default=11)
Same as theretransmitpart of the-t timeout.retransmitoption to Amd.Specifies the number of NFS retransmissions that the kernel will use tocommunicate with Amd.

nfs_retransmit_counter_udp (numeric, default=11)
Same as thenfs_retransmit_counteroption, but for all UDP mounts only.

nfs_retransmit_counter_tcp (numeric, default=11)
Same as thenfs_retransmit_counteroption, but for all TCP mounts only.

nfs_retransmit_counter_toplvl (numeric, default=11)
Same as thenfs_retransmit_counteroption, but only for Amd's top-level UDP mounts.

nfs_retry_interval (numeric, default=8)
Same as thetimeoutpart of the-t timeout.retransmitoption to Amd. Specifies the NFS timeout interval, intenthsof seconds, between NFS/RPC retries (for UDP and TCP).This is the value that the kernel will use tocommunicate with Amd.

Amd relies on the kernel RPC retransmit mechanism to trigger mount retries.The values of thenfs_retransmit_counterand thenfs_retry_intervalparameters change the overall retry interval. Too long an interval givespoor interactive response; too short an interval causes excessive retries.

nfs_retry_interval_udp (numeric, default=8)
Same as thenfs_retry_intervaloption, but for all UDP mounts only.

nfs_retry_interval_tcp (numeric, default=8)
Same as thenfs_retry_intervaloption, but for all TCP mounts only.

nfs_retry_interval_toplvl (numeric, default=8)
Same as thenfs_retry_intervaloption, but only for Amd's top-level UDP mounts.

nfs_vers (numeric, default to trying version 3 then 2)
By default, Amd tries version 3 and then version 2. This option forces theoverall NFS protocol used to version 3 or 2. It overrides what is in theAmd maps, and is useful when Amd is compiled with NFSv3 support that may notbe stable. With this option you can turn off the complete usage of NFSv3dynamically (without having to recompile Amd) until such time as NFSv3support is desired again.

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

normalize_hostnames (boolean, default=no)
Same as the-noption to Amd. If "yes," then the name refereed to by ${rhost} isnormalized relative to the host database before being used. The effect isto translate aliases into ``official'' names.

normalize_slashes (boolean, default=yes)

If "yes," then Amd will condense all multiple ``/'' (slash) characters intoone and remove all trailing slashes. If "no," then Amd will not touchstrings that may contain repeated or trailing slashes. The latter issometimes useful with SMB mounts, which often require multiple slashcharacters in pathnames.

os (string, default to compiled in value)
Same as the-Ooption to Amd. Allows you to override the compiled-in name of the operatingsystem. Useful when the built-in name is not desired for backwardcompatibility reasons. For example, if the build in name is ``sunos5'', youcan override it to ``sos5'', and use older maps which were written with thelatter in mind.

osver (string, default to compiled in value)
Same as the-ooption to Amd. Overrides the compiled-in version number of the operatingsystem. Useful when the built in version is not desired for backwardcompatibility 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 withthe latter in mind.

pid_file (string, default=/dev/stdout)
Specify a file to store the process ID of the running daemon into. If notspecified, Amd will print its process id onto the standard output. Usefulfor killing Amd after it had run. Note that the PID of a running Amd canalso be retrieved viaamq-p.This file is used only if the print_pid option is on.

plock (boolean, default=yes)
Same as the-Soption to Amd.If "yes," lock the running executable pages of Amd into memory. To improveAmd's performance, systems that support theplock(3)ormlockall(2)call can lock the Amd process into memory. This way there is less chance itthe operating system will schedule, page out, and swap the Amd process asneeded. This improves Amd's performance, at the cost of reserving thememory used by the Amd process (making it unavailable for other processes).

portmap_program (numeric, default=300019)
Specify an alternate Port-mapper RPC program number, other than the officialnumber. This is useful when running multiple Amd processes. For example,you can run another Amd in "test" mode, without affecting the primary Amdprocess in any way. For safety reasons, the alternate program numbers thatcan be specified must be in the range 300019-300029, inclusive.Amqhas an option-Pwhich can be used to specify an alternate program number of an Amd tocontact. In this way, amq can fully control any number of Amd processesrunning on the same host.

preferred_amq_port (numeric, default=0)
Specify an alternate Port-mapper RPC port number for Amd'sAmqservice. This is used for both UDP and TCP. Setting this value to 0 (ornot defining it) will causeAmdto select an arbitrary port number. Setting theAmqRPC service port to a specific number is useful in firewalled or NAT'edenvironments, where you need to know which portAmdwill listen on.

print_pid (boolean, default=no)
Same as the-poption to Amd. If "yes," Amd will print its process ID upon starting.

print_version (boolean, default=no)
Same as the-voption to Amd, but the version prints and Amd continues to run. If "yes,"Amd will print its version information string, which includes someconfiguration and compilation values.

restart_mounts (boolean, default=no)
Same as the-roption to Amd. If "yes"Amdwill scan the mount table to determine which file systems are currentlymounted. Whenever one of these would have been auto-mounted,Amdinherits it.

show_statfs_entries (boolean), default=no)
If "yes," then all maps which are browsable will also show the number ofentries (keys) they have when "df" runs. (This is accomplished by returningnon-zero values to the statfs(2) system call).

truncate_log (boolean), default=no)
If "yes," then the log file (if it is a regular file), will be truncatedupon startup.

unmount_on_exit (boolean), default=no)
If "yes," then Amd will attempt to unmount all file systems which it knowsabout. Normally Amd 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 or-rflag are used.

use_tcpwrappers (boolean), default=yes)
If "yes," then Amd will use the tcpd/librwap tcpwrappers library(if available) to controlaccess to Amd via the /etc/hosts.allow and /etc/hosts.deny files.

vendor (string, default to compiled in value)
The name of the vendor of the operating system. Overrides the compiled-invendor name. Useful when the compiled-in name is not desired. For example,most Intel based systems set the vendor name to ``unknown'', but you can setit to ``redhat.''


Parameters applicable to regular map sections

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

tag (string, default no tag)
Each map entry in the configuration file can be tagged. If no tag isspecified, that map section will always be processed by Amd. If it isspecified, then Amd will process the map if the-Toption was given to Amd, and the value given to that command-line optionmatches that in the map section.



Here is a real Amd configuration file I use daily.
# GLOBAL OPTIONS SECTION[ global ]normalize_hostnames =    noprint_pid =              norestart_mounts =         yesauto_dir =               /nlog_file =               /var/log/amdlog_options =            all#debug_options =         allplock =                  noselectors_in_defaults =  yes# config.guess picks up "sunos5" and I don't want to edit my maps yetos =                     sos5# if you print_version after setting up "os," it will show it.print_version =          nomap_type =               filesearch_path =            /etc/amdmaps:/usr/lib/amd:/usr/local/AMD/libbrowsable_dirs =         yes# 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 =                    tftpbootmap_name =               amd.tftpboot




Linux NFS and Automounter Administrationby Erez Zadok, ISBN 0-7821-2739-8, (Sybex, 2001).

Amd - The 4.4 BSD Automounter 


Erez Zadok <>, Computer Science Department, Stony BrookUniversity, Stony Brook, New York, USA.Other authors and contributors to am-utils are listed in theAUTHORSfile distributed with am-utils.



The [global] section
Regular [/map] sections
Parameters common to all sections
Parameters applicable to the global section only
Parameters applicable to regular map sections

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