NAME

       systemd-system.conf, system.conf.d, systemd-user.conf, user.conf.d - System and session
       service manager configuration files

SYNOPSIS

       /etc/systemd/system.conf, /etc/systemd/system.conf.d/*.conf,
       /run/systemd/system.conf.d/*.conf, /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

DESCRIPTION

       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.

CONFIGURATION DIRECTORIES AND PRECEDENCE

       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/. 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.

OPTIONS

       All options are configured in the "[Manager]" section:

       LogLevel=, LogTarget=, LogColor=, LogLocation=, 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 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 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.

       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=,
       DefaultTasksAccounting=
           Configure the default resource accounting settings, as configured per-unit by
           CPUAccounting=, BlockIOAccounting=, MemoryAccounting= and TasksAccounting=. See
           systemd.resource-control(5) for details on the per-unit settings.

       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.

       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. 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) for 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.

SEE ALSO

       systemd(1), systemd.directives(7), systemd.exec(5), systemd.service(5), environ(7),
       capabilities(7)