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.TH "SYSTEMD\-SYSTEM\&.CONF" "5" "" "systemd 241" "systemd-system.conf"
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.SH "NAME"
systemd-system.conf, system.conf.d, systemd-user.conf, user.conf.d \- System and session service manager configuration files
.SH "SYNOPSIS"
.PP
/etc/systemd/system\&.conf,
/etc/systemd/system\&.conf\&.d/*\&.conf,
/run/systemd/system\&.conf\&.d/*\&.conf,
/lib/systemd/system\&.conf\&.d/*\&.conf
.PP
/etc/systemd/user\&.conf,
/etc/systemd/user\&.conf\&.d/*\&.conf,
/run/systemd/user\&.conf\&.d/*\&.conf,
/usr/lib/systemd/user\&.conf\&.d/*\&.conf
.SH "DESCRIPTION"
.PP
When run as a system instance, systemd interprets the configuration file
system\&.conf
and the files in
system\&.conf\&.d
directories; when run as a user instance, systemd interprets the configuration file
user\&.conf
and the files in
user\&.conf\&.d
directories\&. These configuration files contain a few settings controlling basic manager operations\&. See
\fBsystemd.syntax\fR(5)
for a general description of the syntax\&.
.SH "CONFIGURATION DIRECTORIES AND PRECEDENCE"
.PP
The default configuration is defined during compilation, so a configuration file is only needed when it is necessary to deviate from those defaults\&. By default, the configuration file in
/etc/systemd/
contains commented out entries showing the defaults as a guide to the administrator\&. This file can be edited to create local overrides\&.
.PP
When packages need to customize the configuration, they can install configuration snippets in
/usr/lib/systemd/*\&.conf\&.d/\&. Files in
/etc/
are reserved for the local administrator, who may use this logic to override the configuration files installed by vendor packages\&. The main configuration file is read before any of the configuration directories, and has the lowest precedence; entries in a file in any configuration directory override entries in the single configuration file\&. Files in the
*\&.conf\&.d/
configuration subdirectories are sorted by their filename in lexicographic order, regardless of which of the subdirectories they reside in\&. When multiple files specify the same option, for options which accept just a single value, the entry in the file with the lexicographically latest name takes precedence\&. For options which accept a list of values, entries are collected as they occur in files sorted lexicographically\&. It is recommended to prefix all filenames in those subdirectories with a two\-digit number and a dash, to simplify the ordering of the files\&.
.PP
To disable a configuration file supplied by the vendor, the recommended way is to place a symlink to
/dev/null
in the configuration directory in
/etc/, with the same filename as the vendor configuration file\&.
.SH "OPTIONS"
.PP
All options are configured in the
"[Manager]"
section:
.PP
\fILogLevel=\fR, \fILogTarget=\fR, \fILogColor=\fR, \fILogLocation=\fR, \fIDumpCore=yes\fR, \fICrashChangeVT=no\fR, \fICrashShell=no\fR, \fICrashReboot=no\fR, \fIShowStatus=yes\fR, \fIDefaultStandardOutput=journal\fR, \fIDefaultStandardError=inherit\fR
.RS 4
Configures various parameters of basic manager operation\&. These options may be overridden by the respective process and kernel command line arguments\&. See
\fBsystemd\fR(1)
for details\&.
.RE
.PP
\fICtrlAltDelBurstAction=\fR
.RS 4
Defines what action will be performed if user presses Ctrl\-Alt\-Delete more than 7 times in 2s\&. Can be set to
"reboot\-force",
"poweroff\-force",
"reboot\-immediate",
"poweroff\-immediate"
or disabled with
"none"\&. Defaults to
"reboot\-force"\&.
.RE
.PP
\fICPUAffinity=\fR
.RS 4
Configures the CPU affinity for the service manager as well as the default CPU affinity for all forked off processes\&. Takes a list of CPU indices or ranges separated by either whitespace or commas\&. CPU ranges are specified by the lower and upper CPU indices separated by a dash\&. Individual services may override the CPU affinity for their processes with the
\fICPUAffinity=\fR
setting in unit files, see
\fBsystemd.exec\fR(5)\&.
.RE
.PP
\fIRuntimeWatchdogSec=\fR, \fIShutdownWatchdogSec=\fR
.RS 4
Configure the hardware watchdog at runtime and at reboot\&. Takes a timeout value in seconds (or in other time units if suffixed with
"ms",
"min",
"h",
"d",
"w")\&. If
\fIRuntimeWatchdogSec=\fR
is set to a non\-zero value, the watchdog hardware (/dev/watchdog
or the path specified with
\fIWatchdogDevice=\fR
or the kernel option
\fIsystemd\&.watchdog\-device=\fR) will be programmed to automatically reboot the system if it is not contacted within the specified timeout interval\&. The system manager will ensure to contact it at least once in half the specified timeout interval\&. This feature requires a hardware watchdog device to be present, as it is commonly the case in embedded and server systems\&. Not all hardware watchdogs allow configuration of all possible reboot timeout values, in which case the closest available timeout is picked\&.
\fIShutdownWatchdogSec=\fR
may be used to configure the hardware watchdog when the system is asked to reboot\&. It works as a safety net to ensure that the reboot takes place even if a clean reboot attempt times out\&. Note that the
\fIShutdownWatchdogSec=\fR
timeout applies only to the second phase of the reboot, i\&.e\&. after all regular services are already terminated, and after the system and service manager process (PID 1) got replaced by the
systemd\-shutdown
binary, see system
\fBbootup\fR(7)
for details\&. During the first phase of the shutdown operation the system and service manager remains running and hence
\fIRuntimeWatchdogSec=\fR
is still honoured\&. In order to define a timeout on this first phase of system shutdown, configure
\fIJobTimeoutSec=\fR
and
\fIJobTimeoutAction=\fR
in the
"[Unit]"
section of the
shutdown\&.target
unit\&. By default
\fIRuntimeWatchdogSec=\fR
defaults to 0 (off), and
\fIShutdownWatchdogSec=\fR
to 10min\&. These settings have no effect if a hardware watchdog is not available\&.
.RE
.PP
\fIWatchdogDevice=\fR
.RS 4
Configure the hardware watchdog device that the runtime and shutdown watchdog timers will open and use\&. Defaults to
/dev/watchdog\&. This setting has no effect if a hardware watchdog is not available\&.
.RE
.PP
\fICapabilityBoundingSet=\fR
.RS 4
Controls which capabilities to include in the capability bounding set for PID 1 and its children\&. See
\fBcapabilities\fR(7)
for details\&. Takes a whitespace\-separated list of capability names as read by
\fBcap_from_name\fR(3)\&. Capabilities listed will be included in the bounding set, all others are removed\&. If the list of capabilities is prefixed with ~, all but the listed capabilities will be included, the effect of the assignment inverted\&. Note that this option also affects the respective capabilities in the effective, permitted and inheritable capability sets\&. The capability bounding set may also be individually configured for units using the
\fICapabilityBoundingSet=\fR
directive for units, but note that capabilities dropped for PID 1 cannot be regained in individual units, they are lost for good\&.
.RE
.PP
\fINoNewPrivileges=\fR
.RS 4
Takes a boolean argument\&. If true, ensures that PID 1 and all its children can never gain new privileges through
\fBexecve\fR(2)
(e\&.g\&. via setuid or setgid bits, or filesystem capabilities)\&. Defaults to false\&. General purpose distributions commonly rely on executables with setuid or setgid bits and will thus not function properly with this option enabled\&. Individual units cannot disable this option\&. Also see
\m[blue]\fBNo New Privileges Flag\fR\m[]\&\s-2\u[1]\d\s+2\&.
.RE
.PP
\fISystemCallArchitectures=\fR
.RS 4
Takes a space\-separated list of architecture identifiers\&. Selects from which architectures system calls may be invoked on this system\&. This may be used as an effective way to disable invocation of non\-native binaries system\-wide, for example to prohibit execution of 32\-bit x86 binaries on 64\-bit x86\-64 systems\&. This option operates system\-wide, and acts similar to the
\fISystemCallArchitectures=\fR
setting of unit files, see
\fBsystemd.exec\fR(5)
for details\&. This setting defaults to the empty list, in which case no filtering of system calls based on architecture is applied\&. Known architecture identifiers are
"x86",
"x86\-64",
"x32",
"arm"
and the special identifier
"native"\&. The latter implicitly maps to the native architecture of the system (or more specifically, the architecture the system manager was compiled for)\&. Set this setting to
"native"
to prohibit execution of any non\-native binaries\&. When a binary executes a system call of an architecture that is not listed in this setting, it will be immediately terminated with the SIGSYS signal\&.
.RE
.PP
\fITimerSlackNSec=\fR
.RS 4
Sets the timer slack in nanoseconds for PID 1, which is inherited by all executed processes, unless overridden individually, for example with the
\fITimerSlackNSec=\fR
setting in service units (for details see
\fBsystemd.exec\fR(5))\&. The timer slack controls the accuracy of wake\-ups triggered by system timers\&. See
\fBprctl\fR(2)
for more information\&. Note that in contrast to most other time span definitions this parameter takes an integer value in nano\-seconds if no unit is specified\&. The usual time units are understood too\&.
.RE
.PP
\fIDefaultTimerAccuracySec=\fR
.RS 4
Sets the default accuracy of timer units\&. This controls the global default for the
\fIAccuracySec=\fR
setting of timer units, see
\fBsystemd.timer\fR(5)
for details\&.
\fIAccuracySec=\fR
set in individual units override the global default for the specific unit\&. Defaults to 1min\&. Note that the accuracy of timer units is also affected by the configured timer slack for PID 1, see
\fITimerSlackNSec=\fR
above\&.
.RE
.PP
\fIDefaultTimeoutStartSec=\fR, \fIDefaultTimeoutStopSec=\fR, \fIDefaultRestartSec=\fR
.RS 4
Configures the default timeouts for starting and stopping of units, as well as the default time to sleep between automatic restarts of units, as configured per\-unit in
\fITimeoutStartSec=\fR,
\fITimeoutStopSec=\fR
and
\fIRestartSec=\fR
(for services, see
\fBsystemd.service\fR(5)
for details on the per\-unit settings)\&. Disabled by default, when service with
\fIType=oneshot\fR
is used\&. For non\-service units,
\fIDefaultTimeoutStartSec=\fR
sets the default
\fITimeoutSec=\fR
value\&.
\fIDefaultTimeoutStartSec=\fR
and
\fIDefaultTimeoutStopSec=\fR
default to 90s\&.
\fIDefaultRestartSec=\fR
defaults to 100ms\&.
.RE
.PP
\fIDefaultStartLimitIntervalSec=\fR, \fIDefaultStartLimitBurst=\fR
.RS 4
Configure the default unit start rate limiting, as configured per\-service by
\fIStartLimitIntervalSec=\fR
and
\fIStartLimitBurst=\fR\&. See
\fBsystemd.service\fR(5)
for details on the per\-service settings\&.
\fIDefaultStartLimitIntervalSec=\fR
defaults to 10s\&.
\fIDefaultStartLimitBurst=\fR
defaults to 5\&.
.RE
.PP
\fIDefaultEnvironment=\fR
.RS 4
Sets manager environment variables passed to all executed processes\&. Takes a space\-separated list of variable assignments\&. See
\fBenviron\fR(7)
for details about environment variables\&.
.sp
Example:
.sp
.if n \{\
.RS 4
.\}
.nf
DefaultEnvironment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6"
.fi
.if n \{\
.RE
.\}
.sp
Sets three variables
"VAR1",
"VAR2",
"VAR3"\&.
.RE
.PP
\fIDefaultCPUAccounting=\fR, \fIDefaultBlockIOAccounting=\fR, \fIDefaultMemoryAccounting=\fR, \fIDefaultTasksAccounting=\fR, \fIDefaultIOAccounting=\fR, \fIDefaultIPAccounting=\fR
.RS 4
Configure the default resource accounting settings, as configured per\-unit by
\fICPUAccounting=\fR,
\fIBlockIOAccounting=\fR,
\fIMemoryAccounting=\fR,
\fITasksAccounting=\fR,
\fIIOAccounting=\fR
and
\fIIPAccounting=\fR\&. See
\fBsystemd.resource-control\fR(5)
for details on the per\-unit settings\&.
\fIDefaultTasksAccounting=\fR
defaults to yes,
\fIDefaultMemoryAccounting=\fR
to no\&.
\fIDefaultCPUAccounting=\fR
defaults to yes if enabling CPU accounting doesn\*(Aqt require the CPU controller to be enabled (Linux 4\&.15+ using the unified hierarchy for resource control), otherwise it defaults to no\&. The other three settings default to no\&.
.RE
.PP
\fIDefaultTasksMax=\fR
.RS 4
Configure the default value for the per\-unit
\fITasksMax=\fR
setting\&. See
\fBsystemd.resource-control\fR(5)
for details\&. This setting applies to all unit types that support resource control settings, with the exception of slice units\&.
.RE
.PP
\fIDefaultLimitCPU=\fR, \fIDefaultLimitFSIZE=\fR, \fIDefaultLimitDATA=\fR, \fIDefaultLimitSTACK=\fR, \fIDefaultLimitCORE=\fR, \fIDefaultLimitRSS=\fR, \fIDefaultLimitNOFILE=\fR, \fIDefaultLimitAS=\fR, \fIDefaultLimitNPROC=\fR, \fIDefaultLimitMEMLOCK=\fR, \fIDefaultLimitLOCKS=\fR, \fIDefaultLimitSIGPENDING=\fR, \fIDefaultLimitMSGQUEUE=\fR, \fIDefaultLimitNICE=\fR, \fIDefaultLimitRTPRIO=\fR, \fIDefaultLimitRTTIME=\fR
.RS 4
These settings control various default resource limits for units\&. See
\fBsetrlimit\fR(2)
for details\&. The resource limit is possible to specify in two formats,
\fBvalue\fR
to set soft and hard limits to the same value, or
\fBsoft:hard\fR
to set both limits individually (e\&.g\&. DefaultLimitAS=4G:16G)\&. Use the string
\fIinfinity\fR
to configure no limit on a specific resource\&. The multiplicative suffixes K (=1024), M (=1024*1024) and so on for G, T, P and E may be used for resource limits measured in bytes (e\&.g\&. DefaultLimitAS=16G)\&. For the limits referring to time values, the usual time units ms, s, min, h and so on may be used (see
\fBsystemd.time\fR(7)
for details)\&. Note that if no time unit is specified for
\fIDefaultLimitCPU=\fR
the default unit of seconds is implied, while for
\fIDefaultLimitRTTIME=\fR
the default unit of microseconds is implied\&. Also, note that the effective granularity of the limits might influence their enforcement\&. For example, time limits specified for
\fIDefaultLimitCPU=\fR
will be rounded up implicitly to multiples of 1s\&. These settings may be overridden in individual units using the corresponding LimitXXX= directives\&. Note that these resource limits are only defaults for units, they are not applied to PID 1 itself\&.
.RE
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1),
\fBsystemd.directives\fR(7),
\fBsystemd.exec\fR(5),
\fBsystemd.service\fR(5),
\fBenviron\fR(7),
\fBcapabilities\fR(7)
.SH "NOTES"
.IP " 1." 4
No New Privileges Flag
.RS 4
\%https://www.kernel.org/doc/html/latest/userspace-api/no_new_privs.html
.RE