autofs.conf(5) — Linux manual page


AUTOFS.CONF(5)               File Formats Manual              AUTOFS.CONF(5)

NAME         top

       autofs.conf - autofs configuration

DESCRIPTION         top

       Configuration settings used by automount(8) may be changed in the
       configuration file @mapdir@/autofs.conf.

       This file contains two primary sections, autofs and amd.

       Configuration entries may be present at the beginning of the
       configuration file without a section header and are implicitly
       included as part of the autofs section.

       Each section name is enclosed in square brackets with spaces between
       the brackets and the section name. The amd section may be followed by
       further sections, named by the top level mount point path, that
       contain per mount configuration settings.


       Configuration settings available are:

              Sets the default mount timeout in seconds. The internal
              program default is 10 minutes, but the default installed
              configuration overrides this and sets the timeout to 5 minutes
              to be consistent with earlier autofs releases.

              sets the default maximum time to wait for the master map to
              become available if it cannot be read at program start
              (program default 10, wait for 10 seconds then continue).

              Set the default timeout for caching failed key lookups
              (program default 60). If the equivalent command line option is
              given it will override this setting.

              Use the verbose flag when spawning mount(8), and log some
              process info about the requestor and its parent (program
              default "no").

              Set the default time to wait for a response from a spawned
              mount(8) before sending it a SIGTERM. Note that we still need
              to wait for the RPC layer to timeout before the sub-process
              exits so this isn't ideal but it is the best we can do. The
              default is to wait until mount(8) returns without

              Set the default time to wait for a response from a spawned
              umount(8) before sending it a SIGTERM. Note that we still need
              to wait for the RPC layer to timeout before the sub-process
              exits so this isn't ideal but it is the best we can do.

              Maps are browsable by default (program default "yes").

              Set the default protocol that mount.nfs(8) uses when
              performing a mount (program default 3). Autofs needs to know
              the default NFS protocol that mount.nfs(8) uses so it can do
              special case handling for its availability probe for different
              NFS protocols. Since we can't identify this default
              automatically we need to set it in the autofs configuration.

              Determine whether global options, given on the command line or
              per mount in the master map, are appended to map entry options
              or if the map entry options replace the global options
              (program default "yes", append options).

              set default log level "none", "verbose" or "debug" (program
              default "none").

              override the use of a prefix with standard environment
              variables when a program map is executed. Since program maps
              are run as the privileged user setting these standard
              environment variables opens automount(8) to potential user
              privilege escalation when the program map is written in a
              language that can load components from, for example, a user
              home directory (program default "no").

              This configuration option may be used to change the number of
              hash table slots (default 1024).

              This configuration option affects the overhead of searching
              the map entry cache for map entries when there are a large
              number of entries.  It affects the number of entries that must
              be looked at to locate a map entry in the map entry cache. For
              example, the default of 1024 and a direct map with 8000
              entries would result in each slot containing an average of 8
              entries, which should be acceptable.

              However, if excessive CPU usage is observed during automount
              lookups increasing this option can reduce the CPU overhead
              considerably because it reduces the length of the search

              Note that the number of entries in a map doesn't necessarily
              relate to the number of entries used in the map entry cache.

              There are two distinct cases where the map hash table can make
              a significant difference, direct maps and indirect maps that
              use the "browse" option.

              For indirect maps that do not use the "browse" option entries
              are added to the map entry cache at lookup so the number of
              active cache entries, in this case, is usually much less than
              the number of entries in the map. In this last case it would
              be unusual for the map entry cache to grow large enough to
              warrant increasing the default before an event that cleans
              stale entries, a map re-read for example.

              NFS mounts where the host name resolves to more than one IP
              address are probed for availability and to establish the order
              in which mounts to them should be tried. To ensure that mount
              attempts are made only to hosts that are responding and are
              tried in the order of hosts with the quickest response the IP
              address of the host needs to be used for the mount.

              If it is necessary to use the hostname given in the map entry
              for the mount regardless, then set this option to "yes".

              Be aware that if this is done there is no defense against the
              host name resolving to one that isn't responding and while the
              number of attempts at a successful mount will correspond to
              the number of addresses the host name resolves to the order
              will also not correspond to fastest responding hosts.

              The original request to add this log message needed it to be
              unconditional.  That produces, IMHO, unnecessary noise in the
              log so a configuration option has been added to provide the
              ability to turn it off. The default is "no" to maintain the
              current behaviour.

              An option to enable the use of autofs pseudo option "disable".
              This option is used as a hint to user space that the mount
              entry should be ommitted from mount table listings. The
              default is "no" to avoid unexpected changes in behaviour and
              so is an opt-in setting.

              Set the time to wait and retry if sssd returns "no such entry"
              when starting up. When sssd is starting up it can sometimes
              return "no such entry" for a short time until it has read in
              the LDAP map information. Default is 0 seconds, don't wait.

              Set whether to use a mount request log id so that log entries
              for specific mount requests can be easily identified in logs
              that have multiple concurrent requests. Default is don't use
              mount request log ids.

   LDAP Configuration
       Configuration settings available are:

              Set the network response timeout (default 8).  Set timeout
              value for the synchronous API calls. The default is the LDAP
              library default of an infinite timeout.

              Set the network response timeout (default 8).

              A space separated list of server uris of the form
              <proto>://<server>[/] where <proto> can be ldap or ldaps. The
              option can be given multiple times.  Map entries that include
              a server name override this option and it is then not used.
              Default is an empty list in which case either the server given
              in a map entry or the LDAP configured default is used. This
              uri list is read at startup and whenever the daemon receives a
              HUP signal.

              This configuration option can also be used to request autofs
              lookup SRV RRs for a domain of the form <proto>:///[<domain
              dn>]. Note that a trailing "/" is not allowed when using this
              form. If the domain dn is not specified the dns domain name
              (if any) is used to construct the domain dn for the SRV RR
              lookup. The server list returned from an SRV RR lookup is
              refreshed according to the minimum ttl found in the SRV RR
              records or after one hour, whichever is less.

              The base dn to use when searching for amap base dn. This entry
              may be given multiple times and each will be checked for a map
              base dn in the order they occur in the configuration. The
              search base list is read at startup and whenever the daemon
              recieves a HUP signal.

              The map object class. In the nisMap schema this corresponds to
              the class nisMap and in the automountMap schema it corresponds
              to the class automountMap.

              The map entry object class. In the nisMap schema this
              corresponds to the class nisObject and in the automountMap
              schema it corresponds to the class automount.

              The attribute used to identify the name of the map to which
              this entry belongs.  In the nisMap schema this corresponds to
              the attribute nisMapName and in the automountMap schema it
              corresponds to the attribute ou or automountMapName.

              The attribute used to identify a map key. In the nisMap schema
              this corresponds to the attribute cn and in the automountMap
              schema it corresponds to the attribute automountKey.

              The attribute used to identify the value of the map entry. In
              the nisMap schema this corresponds to the attribute
              nisMapEntry and in the automountMap schema it corresponds to
              the attribute automountInformation.

       NOTE:  It is essential that entries use class and attribute in a
              consistent manner for correct operation of autofs. For example
              mixing cn and automountKey attributes in automount schema will
              not work as expected.

              This configuration option may be used to specify an alternate
              location for the ldap authentication configuration file. See
              autofs_ldap_auth.conf(5) for more information.


       A number of the amd configuration options are not used by autofs,
       some because they are not relevant within autofs, some because they
       are done differently in autofs and others that are not yet

       Since mount_type is always autofs (because there's no user space NFS
       server) the configuration entries relating to that aren't used.
       Also, server availability is done differently within autofs so the
       options that relate to the amd server monitoring sub-system are also
       not used.

       These options are mount_type, auto_attrcache, portmap_program,
       nfs_vers_ping, nfs_allow_any_interface, nfs_allow_insecure_port,
       nfs_proto, nfs_retransmit_counter, nfs_retransmit_counter_udp,
       nfs_retransmit_counter_tcp, nfs_retransmit_counter_toplvl,
       nfs_retry_interval, nfs_retry_interval_udp, nfs_retry_interval_tcp,
       nfs_retry_interval_toplvl and nfs_vers.

       Other options that are not used within the autofs implementation:

       log_file, truncate_log
              sends its output to syslog so an alternate log file (or
              truncating the log) can't be used.

              There's no corresponding option for this within autofs.

       use_tcpwrappers, show_statfs_entries
              There's no user space NFS server to control access to so this
              option isn't relevant. The show_statfs_entries can't be
              implemented for the same reason.

              There's no user space NFS server and autofs avoids using file
              based mtab whenever possible.

              Sun map format is handled by autofs itself.

       plock, show_statfs_entries, preferred_amq_port
              Are not supported by autofs.

       ldap_cache_maxmem, ldap_cache_seconds
              External ldap caching is not used by autofs.

              autofs always attempts to use the highest available ldap
              protocol version.

       cache_duration, map_reload_interval, map_options
              The map   entry cache is continually updated and stale entries
              cleaned on re-load, which is done when map changes are
              detected so these configuration entries are not used by
              autofs. An exception to this is the case where the map is
              large. In this case it may be necessary to read the whole map
              at startup even if browsing is not enabled. Adding the
              cache:=all option to map_options can be used to for this.

              This is not used within autofs. This configuration option was
              only used in the amd user space server code and is not
              relevant within autofs.

       Options that are handled differently within autofs:

              To specify a pid file name a command line option must be used
              on startup.

              Program version and feature information is obtained by using
              the automount command line option "-V".

       debug_options ,  log_options
              autofs has somewhat more limited logging and debug logging
              options.  When the log_options options is encountered it is
              converted to the nearest matching autofs logging option. Since
              the configuration option debug_options would be handled the
              same way it is ignored.

              This option has no sensible meaning within autofs because
              autofs always tries to re-connect to existing mounts. While
              this has its own set of problems not re-connecting to existing
              mounts always results in a non-functional automount tree if
              mounts were busy at the last shutdown (as is also the case
              with amd when using mount_type autofs).

              Detaching mounts often causes serious problems for users of
              existing mounts. It is used by autofs in some cases, either at
              the explicit request of the user (with a command line or init
              option) and in some special cases during program operation but
              is avoided whenever possible.

       A number of configuration options are not yet implemented:

              Always a little frustrating, the compiled in map location
              should be used to locate maps but isn't in some cases. This
              requires work within autofs itself and that will (obviously)
              include implementing this configuration option for the amd map
              parser as well.

              Not yet implemented.

              Since autofs always tries to re-connect to mounts left mounted
              from a previous shutdown this is a sensible option to
              implement and that will be done.

              Allow map keys to be shown in directory listings. This option
              can have values of "yes" or "no". The default is "no". A
              variation of this option, "browsable", can be used as a pseudo
              mount option in type "auto" map entries to provide browsing
              functionality in sub-mounts. The amd "browsable_dirs = full"
              option cannot be implemented within the current autofs
              framework and is not supported.

              A timeout is not currently used for program maps but this
              might be implemented in the future.

              The tag option is not implemented within autofs.

       Supported options:

       arch, karch, os, osver
              These options default to what is returned from uname(2) and
              can be overridden if required.

              This option has no default and must be set in the
              configuration if used in maps.

              If not set defaults to the host domain name. This option
              corresponds to the HP_UX cluster name (according to the amd
              source) and is probably not used in Linux but is set anyway.

       vendor This option has a default value of "unknown", it must be set
              in the configuration if used in maps.

              Is the base name of the mount tree used for external mounts
              that are sometimes needed by amd maps. Its default value is

              Specifies the autofs map source, such as file, nis, ldap etc.
              and has no default value set.

              This option is used to override /defaults entries within maps
              and can be used to provide different defaults on specific
              machines without having to modify centrally managed maps. It
              is empty by default.

              Colon separated paths to search for maps that are not
              specified as a full path.

              Is equivalent to the autofs timeout option. It is only
              possible to use this with type "auto" mounts due to the way
              the autofs kernel module performs expiry. It takes its default
              value from the autofs internal default of 600 seconds.

              If set to "yes" autofs will attempt to use bind mounts for
              type "link" entries when possible (default is "yes").

              Allows setting of a domain name other than the system default.

              Is used to override (or set) the host domain name.

              If set to "yes" then the contents of ${rhost} is translated in
              its official host name.

              If set to "yes" the domain name part of the host is stripped
              when normalizing hostnames. This can be useful when using of
              the same maps in a multiple domain environment.

              This option is set to "yes" by default and will collapse
              multiple unescaped occurrences of "/" to a single "/".

       selectors_in_defaults, selectors_on_default
              This option has a default value of "no". If set to "yes" then
              any defaults entry will be checked for selectors to determine
              the values to be used. selectors_in_defaults is the preferred
              option to use.

              iThis option has no default value. It must be set to the base
              dn that is used for queries if ldap is to be used as a map

              This option has no default value set. It must be set to the
              URI of the LDAP server to be used for lookups when ldap is
              used as a map source. It may contain a comma or space
              separated list of LDAP URIs.

              Sets the base name used for hesiod map sources.

              This is an additional configuration option for the autofs amd
              format parser implementation.

              There's no simple way to determine what the system default
              filesystem is and am-utils needs to be continually updated to
              do this and can easily get it wrong ayway. So allow it to be
              set in the configuration.

EXAMPLE         top

         [ autofs ]
         timeout = 300
         browse_mode = no

         [ amd ]
         dismount_interval = 300
         map_type = nis
         autofs_use_lofs = no

         [ /expamle/mount ]
         dismount_interval = 60
         map_type = file

SEE ALSO         top

       automount(8), auto.master(5), autofs_ldap_auth.conf(5).

AUTHOR         top

       This manual page was written by Ian Kent <>.

COLOPHON         top

       This page is part of the autofs (automount) project.  Information
       about the project can be found at ⟨⟩.  If you
       have a bug report for this manual page, send it to  This page was obtained from the project's
       upstream Git repository
       ⟨git://⟩ on
       2020-09-18.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-08-25.)  If you discover any
       rendering problems in this HTML version of the page, or you believe
       there is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

                                 23 Jan 2014                  AUTOFS.CONF(5)

Pages that refer to this page: autofs(5)autofs_ldap_auth.conf(5)auto.master(5)autofs(8)automount(8)