system.conf.d(5)



SYSTEMD-SYSTEM.CONF(5)        systemd-system.conf       SYSTEMD-SYSTEM.CONF(5)

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. See
       systemd.syntax(5) for a general description of the syntax.

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/ or
       /usr/local/lib/systemd/*.conf.d/. 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 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 with the
       lexicographically latest name takes precedence. For options which
       accept a list of values, entries are collected as they occur in files
       sorted lexicographically.

       Files in /etc/ are reserved for the local administrator, who may use
       this logic to override the configuration files installed by vendor
       packages. 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 process and kernel
           command line arguments. See systemd(1) for details.

       CtrlAltDelBurstAction=
           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".

       CPUAffinity=
           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 systemd.exec(5).

       NUMAPolicy=
           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).

       NUMAMask=
           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
           shutdown.target 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.

       WatchdogDevice=
           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.

       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.

       NoNewPrivileges=
           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].

       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.

       StatusUnitFormat=
           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
           systemd.unit(5).

       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=,
       DefaultTimeoutAbortSec=, DefaultRestartSec=
           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.

       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=,
       DefaultIOAccounting=, DefaultIPAccounting=
           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.

       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
           processes executed by units. See setrlimit(2) for details. These
           settings may be overridden in individual units using the
           corresponding LimitXXX= directives, see systemd.exec(5), for
           details, and they accept the same parameter syntax. Note that these
           resource limits are only defaults for units, they are not applied
           to the service manager process (i.e. PID 1) itself.

       DefaultOOMPolicy=
           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.

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

NOTES
        1. No New Privileges Flag
           https://www.kernel.org/doc/html/latest/userspace-api/no_new_privs.html

systemd 245                                             SYSTEMD-SYSTEM.CONF(5)

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