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NAME | SYNOPSIS | DESCRIPTION | CONFIGURATION DIRECTORIES AND PRECEDENCE | OPTIONS | SEE ALSO | NOTES | COLOPHON |
SYSTEMD-SYSTEM.CONF(5) systemd-system.conf SYSTEMD-SYSTEM.CONF(5)
systemd-system.conf, system.conf.d, systemd-user.conf, user.conf.d -
System and session service manager configuration files
/etc/systemd/system.conf, /etc/systemd/system.conf.d/*.conf,
/run/systemd/system.conf.d/*.conf,
/usr/lib/systemd/system.conf.d/*.conf
/etc/systemd/user.conf, /etc/systemd/user.conf.d/*.conf,
/run/systemd/user.conf.d/*.conf, /usr/lib/systemd/user.conf.d/*.conf
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 systemd.syntax(7) for a general description of the
syntax.
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.
When packages need to customize the configuration, they can install
configuration snippets in /usr/lib/systemd/*.conf.d/ or
/usr/local/lib/systemd/*.conf.d/. 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 in which of the subdirectories
they reside. 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.
Files in /etc/ are reserved for the local administrator, who may use
this logic to override the configuration files installed by vendor
packages. 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.
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.
All options are configured in the [Manager] section:
LogColor=, LogLevel=, LogLocation=, LogTarget=, LogTime=,
DumpCore=yes, CrashChangeVT=no, CrashShell=no, CrashReboot=no,
ShowStatus=yes, DefaultStandardOutput=journal,
DefaultStandardError=inherit
Configures various parameters of basic manager operation. These
options may be overridden by the respective process and kernel
command line arguments. See systemd(1) for details.
CtrlAltDelBurstAction=
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".
CPUAffinity=
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. This option may be specified more
than once, in which case the specified CPU affinity masks are
merged. If the empty string is assigned, the mask is reset, all
assignments prior to this will have no effect. Individual
services may override the CPU affinity for their processes with
the CPUAffinity= setting in unit files, see systemd.exec(5).
NUMAPolicy=
Configures the NUMA memory policy for the service manager and the
default NUMA memory policy for all forked off processes.
Individual services may override the default policy with the
NUMAPolicy= setting in unit files, see systemd.exec(5).
NUMAMask=
Configures the NUMA node mask that will be associated with the
selected NUMA policy. Note that default and local NUMA policies
don't require explicit NUMA node mask and value of the option can
be empty. Similarly to NUMAPolicy=, value can be overridden by
individual services in unit files, see systemd.exec(5).
RuntimeWatchdogSec=, RebootWatchdogSec=, KExecWatchdogSec=
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 RuntimeWatchdogSec= is set to a
non-zero value, the watchdog hardware (/dev/watchdog or the path
specified with WatchdogDevice= or the kernel option
systemd.watchdog-device=) 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. RebootWatchdogSec= 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 RebootWatchdogSec= 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 bootup(7) for details. During
the first phase of the shutdown operation the system and service
manager remains running and hence RuntimeWatchdogSec= is still
honoured. In order to define a timeout on this first phase of
system shutdown, configure JobTimeoutSec= and JobTimeoutAction=
in the [Unit] section of the shutdown.target unit. By default
RuntimeWatchdogSec= defaults to 0 (off), and RebootWatchdogSec=
to 10min. KExecWatchdogSec= may be used to additionally enable
the watchdog when kexec is being executed rather than when
rebooting. Note that if the kernel does not reset the watchdog on
kexec (depending on the specific hardware and/or driver), in this
case the watchdog might not get disabled after kexec succeeds and
thus the system might get rebooted, unless RuntimeWatchdogSec= is
also enabled at the same time. For this reason it is recommended
to enable KExecWatchdogSec= only if RuntimeWatchdogSec= is also
enabled. These settings have no effect if a hardware watchdog is
not available.
WatchdogDevice=
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.
CapabilityBoundingSet=
Controls which capabilities to include in the capability bounding
set for PID 1 and its children. See capabilities(7) for details.
Takes a whitespace-separated list of capability names as read by
cap_from_name(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 CapabilityBoundingSet= directive for units, but note that
capabilities dropped for PID 1 cannot be regained in individual
units, they are lost for good.
NoNewPrivileges=
Takes a boolean argument. If true, ensures that PID 1 and all its
children can never gain new privileges through execve(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 No New Privileges Flag[1].
SystemCallArchitectures=
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 SystemCallArchitectures= setting of unit files, see
systemd.exec(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.
TimerSlackNSec=
Sets the timer slack in nanoseconds for PID 1, which is inherited
by all executed processes, unless overridden individually, for
example with the TimerSlackNSec= setting in service units (for
details see systemd.exec(5)). The timer slack controls the
accuracy of wake-ups triggered by system timers. See prctl(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.
StatusUnitFormat=
Takes either name or description as the value. If name, the
system manager will use unit names in status messages, instead of
the longer and more informative descriptions set with
Description=, see systemd.unit(5).
DefaultTimerAccuracySec=
Sets the default accuracy of timer units. This controls the
global default for the AccuracySec= setting of timer units, see
systemd.timer(5) for details. AccuracySec= 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 TimerSlackNSec=
above.
DefaultTimeoutStartSec=, DefaultTimeoutStopSec=,
DefaultTimeoutAbortSec=, DefaultRestartSec=
Configures the default timeouts for starting, stopping and
aborting of units, as well as the default time to sleep between
automatic restarts of units, as configured per-unit in
TimeoutStartSec=, TimeoutStopSec=, TimeoutAbortSec= and
RestartSec= (for services, see systemd.service(5) for details on
the per-unit settings). Disabled by default, when service with
Type=oneshot is used. For non-service units,
DefaultTimeoutStartSec= sets the default TimeoutSec= value.
DefaultTimeoutStartSec= and DefaultTimeoutStopSec= default to
90s. DefaultTimeoutAbortSec= is not set by default so that all
units fall back to TimeoutStopSec=. DefaultRestartSec= defaults
to 100ms.
DefaultStartLimitIntervalSec=, DefaultStartLimitBurst=
Configure the default unit start rate limiting, as configured
per-service by StartLimitIntervalSec= and StartLimitBurst=. See
systemd.service(5) for details on the per-service settings.
DefaultStartLimitIntervalSec= defaults to 10s.
DefaultStartLimitBurst= defaults to 5.
DefaultEnvironment=
Sets manager environment variables passed to all executed
processes. Takes a space-separated list of variable assignments.
See environ(7) for details about environment variables.
Example:
DefaultEnvironment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6"
Sets three variables "VAR1", "VAR2", "VAR3".
DefaultCPUAccounting=, DefaultBlockIOAccounting=,
DefaultMemoryAccounting=, DefaultTasksAccounting=,
DefaultIOAccounting=, DefaultIPAccounting=
Configure the default resource accounting settings, as configured
per-unit by CPUAccounting=, BlockIOAccounting=,
MemoryAccounting=, TasksAccounting=, IOAccounting= and
IPAccounting=. See systemd.resource-control(5) for details on the
per-unit settings. DefaultTasksAccounting= defaults to yes,
DefaultMemoryAccounting= to yes. DefaultCPUAccounting= defaults
to yes if enabling CPU accounting doesn't 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.
DefaultTasksMax=
Configure the default value for the per-unit TasksMax= setting.
See systemd.resource-control(5) for details. This setting applies
to all unit types that support resource control settings, with
the exception of slice units. Defaults to 15%, which equals 4915
with the kernel's defaults on the host, but might be smaller in
OS containers.
DefaultLimitCPU=, DefaultLimitFSIZE=, DefaultLimitDATA=,
DefaultLimitSTACK=, DefaultLimitCORE=, DefaultLimitRSS=,
DefaultLimitNOFILE=, DefaultLimitAS=, DefaultLimitNPROC=,
DefaultLimitMEMLOCK=, DefaultLimitLOCKS=, DefaultLimitSIGPENDING=,
DefaultLimitMSGQUEUE=, DefaultLimitNICE=, DefaultLimitRTPRIO=,
DefaultLimitRTTIME=
These settings control various default resource limits for
processes executed by units. See setrlimit(2) for details. These
settings may be overridden in individual units using the
corresponding LimitXXX= directives and they accept the same
parameter syntax, see systemd.exec(5) for details. Note that
these resource limits are only defaults for units, they are not
applied to the service manager process (i.e. PID 1) itself.
DefaultOOMPolicy=
Configure the default policy for reacting to processes being
killed by the Linux Out-Of-Memory (OOM) killer. This may be used
to pick a global default for the per-unit OOMPolicy= setting. See
systemd.service(5) for details. Note that this default is not
used for services that have Delegate= turned on.
systemd(1), systemd.directives(7), systemd.exec(5),
systemd.service(5), environ(7), capabilities(7)
1. No New Privileges Flag
https://www.kernel.org/doc/html/latest/userspace-api/no_new_privs.html
This page is part of the systemd (systemd system and service manager)
project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug
report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This
page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2020-08-13. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2020-08-11.) 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
systemd 246 SYSTEMD-SYSTEM.CONF(5)
Pages that refer to this page: 30-systemd-environment-d-generator(7) , systemd.index(7)