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.
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/
. 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. If multiple files
specify the same option, the entry in the file with the
lexicographically latest name takes precedence. 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:
LogLevel=
, LogTarget=
, LogColor=
, LogLocation=
, DumpCore=yes
, CrashShell=no
, ShowStatus=yes
, CrashChVT=1
, DefaultStandardOutput=journal
, DefaultStandardError=inherit
¶Configures various parameters of basic manager operation. These options may be overridden by the respective command line arguments. See systemd(1) for details about these command line arguments.
CPUAffinity=
¶Configures the initial CPU affinity for the init process. Takes a space-separated list of CPU indices.
JoinControllers=cpu,cpuacct net_cls,netprio
¶Configures controllers that shall be mounted in a single hierarchy. By default, systemd will mount all controllers which are enabled in the kernel in individual hierarchies, with the exception of those listed in this setting. Takes a space-separated list of comma-separated controller names, in order to allow multiple joined hierarchies. Defaults to 'cpu,cpuacct'. Pass an empty string to ensure that systemd mounts all controllers in separate hierarchies.
Note that this option is only applied once, at very early boot. If you use an initial RAM disk (initrd) that uses systemd, it might hence be necessary to rebuild the initrd if this option is changed, and make sure the new configuration file is included in it. Otherwise, the initrd might mount the controller hierarchies in a different configuration than intended, and the main system cannot remount them anymore.
RuntimeWatchdogSec=
, ShutdownWatchdogSec=
¶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
) 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 the
reboot timeout, in which case the closest available timeout is
picked. ShutdownWatchdogSec=
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. By
default RuntimeWatchdogSec=
defaults to 0
(off), and ShutdownWatchdogSec=
to 10min.
These settings have 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.
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.
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=
, DefaultRestartSec=
¶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=
,
TimeoutStopSec=
and
RestartSec=
(for services, see
systemd.service(5)
for details on the per-unit settings). For non-service units,
DefaultTimeoutStartSec=
sets the default
TimeoutSec=
value. DefaultTimeoutStartSec=
and
DefaultTimeoutStopSec=
default to
90s. DefaultRestartSec=
defaults to
100ms.
DefaultStartLimitInterval=
, DefaultStartLimitBurst=
¶Configure the default unit start rate
limiting, as configured per-service by
StartLimitInterval=
and
StartLimitBurst=
. See
systemd.service(5)
for details on the per-service settings.
DefaultStartLimitInterval=
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=
¶Configure the default resource accounting
settings, as configured per-unit by
CPUAccounting=
,
BlockIOAccounting=
and
MemoryAccounting=
. See
systemd.resource-control(5)
for details on the per-unit settings.
DefaultLimitCPU=
, DefaultLimitFSIZE=
, DefaultLimitDATA=
, DefaultLimitSTACK=
, DefaultLimitCORE=
, DefaultLimitRSS=
, DefaultLimitNOFILE=
, DefaultLimitAS=
, DefaultLimitNPROC=
, DefaultLimitMEMLOCK=
, DefaultLimitLOCKS=
, DefaultLimitSIGPENDING=
, DefaultLimitMSGQUEUE=
, DefaultLimitNICE=
, DefaultLimitRTPRIO=
, DefaultLimitRTTIME=
¶These settings control various default
resource limits for units. See
setrlimit(2)
for details. Use the string infinity
to
configure no limit on a specific resource. 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.