All options are configured in the "[Manager]" section:
LogLevel=, LogTarget=, LogColor=,
LogLocation=, DumpCore=yes, CrashChangeVT=no,
CrashShell=no, CrashReboot=no, ShowStatus=yes,
Configures various parameters of basic manager operation.
These options may be overridden by the respective process and kernel command
line arguments. See systemd(1)
Defines what action will be performed if user presses
Ctrl-Alt-Delete more than 7 times in 2s. Can be set to
"reboot-immediate", "poweroff-immediate" or disabled with
"none". Defaults to "reboot-force".
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
setting in unit files, see systemd.exec(5)
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").
is set to a non-zero value, the watchdog
hardware (/dev/watchdog or the path specified with WatchdogDevice=
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.
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
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
in the "[Unit]"
section of the shutdown.target unit. By default RuntimeWatchdogSec=
defaults to 0 (off), and ShutdownWatchdogSec=
to 10min. These settings
have no effect if a hardware watchdog is not available.
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.
Controls which capabilities to include in the capability
bounding set for PID 1 and its children. See capabilities(7)
details. Takes a whitespace-separated list of capability names as read by
. 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
directive for units, but note that capabilities
dropped for PID 1 cannot be regained in individual units, they are lost for
Takes a boolean argument. If true, ensures that PID 1 and
all its children can never gain new privileges through execve(2)
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
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
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.
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
). 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.
Sets the default accuracy of timer units. This controls
the global default for the AccuracySec=
setting of timer units, see
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=
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 TimeoutStartSec=
(for services, see
for details on the per-unit settings). Disabled by
default, when service with Type=oneshot
is used. For non-service units,
sets the default TimeoutSec=
defaults to 100ms.
Configure the default unit start rate limiting, as
configured per-service by StartLimitIntervalSec=
. See systemd.service(5)
for details on the
per-service settings. DefaultStartLimitIntervalSec=
defaults to 10s.
defaults to 5.
Sets manager environment variables passed to all executed
processes. Takes a space-separated list of variable assignments. See
for details about environment variables.
DefaultEnvironment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6"
Sets three variables "VAR1", "VAR2",
Configure the default resource accounting settings, as
configured per-unit by CPUAccounting=
. See systemd.resource-control(5)
for details on
the per-unit settings. DefaultTasksAccounting=
defaults to yes,
to yes. DefaultCPUAccounting=
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.
Configure the default value for the per-unit
setting. See systemd.resource-control(5)
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.
These settings control various default resource limits
for units. See setrlimit(2)
for details. The resource limit is possible
to specify in two formats, value
to set soft and hard limits to the
same value, or soft:hard
to set both limits individually (e.g.
DefaultLimitAS=4G:16G). Use the string infinity
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 systemd.time(7)
details). Note that if no time unit is specified for DefaultLimitCPU=
the default unit of seconds is implied, while for DefaultLimitRTTIME=
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 DefaultLimitCPU=
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.