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, /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.


   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.


   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.

       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

       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.

       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.

       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.

       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.

       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.

   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.

       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.


           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.  DefaultTasksAccounting= defaults to on,
       the other three settings to off.

       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=,
       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.


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


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