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NAME | DESCRIPTION | SECTION autofs CONFIGURATION OPTIONS | SECTION amd CONFIGURATION OPTIONS | EXAMPLE | SEE ALSO | AUTHOR | COLOPHON |
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AUTOFS.CONF(5) File Formats Manual AUTOFS.CONF(5)
autofs.conf - autofs configuration
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:
+.B open_file_limit
+.br +Set the maximum number of open files. Note there may
be other limits +within the system that prevent this from
being set, systemd for example +may need a setting in the
unit file to increase its default. The autofs +default is
20480. +.TP timeout
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.
master_wait
Sets the default maximum number of retries (actaul
iterations is half this, each is delayed by 2 seconds
before retrying) waiting for the master map to become
available if it cannot be read at program start (program
default 10, then continue). This can be longer if the map
source itself waits for availability (such as sss).
negative_timeout
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.
positive_timeout
Set the default timeout for using cached map entries
(program default 120). If the equivalent command line
option is given it will override this setting.
mount_verbose
Use the verbose flag when spawning mount(8), and log some
process info about the requestor and its parent (program
default "no").
mount_wait
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
intervention.
umount_wait
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.
browse_mode
Maps are browsable by default (program default "yes").
mount_nfs_default_protocol
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.
append_options
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).
logging
set default log level "none", "verbose" or "debug" (program
default "none").
force_standard_program_map_env
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").
map_hash_table_size
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 chains.
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.
use_hostname_for_mounts
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.
disable_not_found_message
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.
use_ignore_mount_option
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.
sss_master_map_wait
Set the time to wait and retry if sssd is unable to read
the master map at program start. Program default is 0
(don't wait) or 10 if sss supports returning EHSTDOWN when
the provider isn't available.
If the sss library supports returning EHOSTDOWN when the
provider is down then this value is how long to wait
between retries reading the master map. When reading
dependent maps or looking up a map key this value is
multiplied by the number of retries that would be used when
reading the master map.
use_mount_request_log_id
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:
ldap_timeout
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.
ldap_network_timeout
Set the network response timeout (default 8).
ldap_uri
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.
search_base
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.
map_object_class
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.
entry_object_class
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.
map_attribute
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.
entry_attribute
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.
value_attribute
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.
auth_conf_file
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
implemented.
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.
print_pid
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.
debug_mtab_file
There's no user space NFS server and autofs avoids using
file based mtab whenever possible.
sun_map_syntax
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.
ldap_proto_version
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.
localhost_address
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:
pid_file
To specify a pid file name a command line option must be
used on startup.
print_version
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.
restart_mounts
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).
forced_unmounts
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:
search_path
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.
fully_qualified_hosts
Not yet implemented.
unmount_on_exit
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.
browsable_dirs
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.
exec_map_timeout
A timeout is not currently used for program maps but this
might be implemented in the future.
tag
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.
full_os
This option has no default and must be set in the
configuration if used in maps.
cluster
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.
auto_dir
Is the base name of the mount tree used for external mounts
that are sometimes needed by amd maps. Its default value is
"/a".
map_type
Specifies the autofs map source, such as file, nis, ldap
etc. and has no default value set.
map_defaults
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.
search_path
Colon separated paths to search for maps that are not
specified as a full path.
dismount_interval
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.
autofs_use_lofs
If set to "yes" autofs will attempt to use bind mounts for
type "link" entries when possible (default is "yes").
nis_domain
Allows setting of a domain name other than the system
default.
local_domain
Is used to override (or set) the host domain name.
normalize_hostnames
If set to "yes" then the contents of ${rhost} is translated
in its official host name.
domain_strip
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.
normalize_slashes
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.
ldap_base
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 source.
ldap_hostports
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.
hesiod_base
Sets the base name used for hesiod map sources.
linux_ufs_mount_type
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.
[ 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
automount(8), auto.master(5), autofs_ldap_auth.conf(5).
This manual page was written by Ian Kent <raven@themaw.net>.
This page is part of the autofs (automount) project. Information
about the project can be found at ⟨http://www.autofs.org/⟩. If
you have a bug report for this manual page, send it to
autofs@vger.kernel.org. This page was obtained from the project's
upstream Git repository
⟨git://git.kernel.org/pub/scm/linux/storage/autofs/autofs.git⟩ on
2025-08-11. (At that time, the date of the most recent commit
that was found in the repository was 2024-08-14.) 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 man-pages@man7.org
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)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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