Ubuntu Manpage: autofs.conf - autofs configuration

Provided by: autofs_5.1.9-1ubuntu4_amd64

NAME

       autofs.conf - autofs configuration

DESCRIPTION

       Configuration  settings  used  by  automount(8)  may  be changed in the configuration file
       /etc/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.

SECTION autofs CONFIGURATION OPTIONS

Configuration settings available are:

open_file_limit
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.

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 (actual 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 omitted 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 receives 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.

SECTION amd CONFIGURATION OPTIONS

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.

EXAMPLE

         [ 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

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