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 set during compilation, so configuration is
       only needed when it is necessary to deviate from those defaults.
       Initially, the main configuration file in /etc/systemd/ contains
       commented out entries showing the defaults as a guide to the
       administrator. Local overrides can be created by editing this file or by
       creating drop-ins, as described below. Using drop-ins for local
       configuration is recommended over modifications to the main configuration

       In addition to the "main" configuration file, drop-in configuration
       snippets are read from /usr/lib/systemd/*.conf.d/,
       /usr/local/lib/systemd/*.conf.d/, and /etc/systemd/*.conf.d/. Those
       drop-ins have higher precedence and override the main 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
       sorted last takes precedence, and for options which accept a list of
       values, entries are collected as they occur in the sorted files.

       When packages need to customize the configuration, they can install
       drop-ins under /usr/. Files in /etc/ are reserved for the local
       administrator, who may use this logic to override the configuration files
       installed by vendor packages. Drop-ins have to be used to override
       package drop-ins, since the main configuration file has lower 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:

       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.

           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".

           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

           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).

           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 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.

           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) 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 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].

           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.

           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

           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=,
           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.

           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=, DefaultIOAccounting=,
           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.

           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% of the minimum of kernel.pid_max=,
           kernel.threads-max= and root cgroup pids.max. Kernel has a default
           value for kernel.pid_max= and an algorithm of counting in case of
           more than 32 cores. For example with the default kernel.pid_max=,
           DefaultTasksMax= defaults to 4915, but might be greater in other
           systems or smaller in OS containers.

       DefaultLimitCPU=, DefaultLimitFSIZE=, DefaultLimitDATA=,
       DefaultLimitSTACK=, DefaultLimitCORE=, DefaultLimitRSS=,
       DefaultLimitNOFILE=, DefaultLimitAS=, DefaultLimitNPROC=,
       DefaultLimitMEMLOCK=, DefaultLimitLOCKS=, DefaultLimitSIGPENDING=,
       DefaultLimitMSGQUEUE=, DefaultLimitNICE=, DefaultLimitRTPRIO=,
           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.

           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

systemd 247                                               SYSTEMD-SYSTEM.CONF(5)