systemd-system.conf(5) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | CONFIGURATION DIRECTORIES AND PRECEDENCE | OPTIONS | RESOURCE MANAGEMENT | HARDWARE WATCHDOG | SECURITY | TIMEOUTS AND RATE LIMITS | ENVIRONMENT | SPECIFIERS | HISTORY | SEE ALSO | NOTES | COLOPHON

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

NAME         top

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

SYNOPSIS         top

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

       ~/.config/systemd/user.conf, /etc/systemd/user.conf,
       /run/systemd/user.conf, /usr/lib/systemd/user.conf,
       /etc/systemd/user.conf.d/*.conf, /run/systemd/user.conf.d/*.conf,
       /usr/lib/systemd/user.conf.d/*.conf

DESCRIPTION         top

       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, it interprets the
       configuration file user.conf (in order of priority, in the home
       directory of the user and under /etc/systemd/, /run/systemd/, and
       /usr/lib/systemd/) 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.

CONFIGURATION DIRECTORIES AND PRECEDENCE         top

       The default configuration is set during compilation, so
       configuration is only needed when it is necessary to deviate from
       those defaults. The main configuration file is loaded from one of
       the listed directories in order of priority, only the first file
       found is used: /etc/systemd/, /run/systemd/,
       /usr/local/lib/systemd/ [1], /usr/lib/systemd/. The vendor version
       of the file contains commented out entries showing the defaults as
       a guide to the administrator. Local overrides can also be created
       by creating drop-ins, as described below. The main configuration
       file can also be edited for this purpose (or a copy in /etc/ if it
       is shipped under /usr/), however using drop-ins for local
       configuration is recommended over modifications to the main
       configuration file.

       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. This also defines a concept of
       drop-in priorities to allow OS vendors to ship drop-ins within a
       specific range lower than the range used by users. This should
       lower the risk of package drop-ins overriding accidentally
       drop-ins defined by users. It is recommended to use the range
       10-40 for drop-ins in /usr/ and the range 60-90 for drop-ins in
       /etc/ and /run/, to make sure that local and transient drop-ins
       take priority over drop-ins shipped by the OS vendor.

       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         top

       All options are configured in the [Manager] section:

       LogColor=, LogLevel=, LogLocation=, LogTarget=, LogTime=,
       DumpCore=yes, CrashChangeVT=no, CrashShell=no, CrashAction=freeze,
       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.

           Added in version 198.

       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".

           Added in version 232.

       StatusUnitFormat=
           Takes name, description or combined as the value. If name, the
           system manager will use unit names in status messages (e.g.
           "systemd-journald.service"), instead of the longer and more
           informative descriptions set with Description= (e.g.  "Journal
           Logging Service"). If combined, the system manager will use
           both unit names and descriptions in status messages (e.g.
           "systemd-journald.service - Journal Logging Service").

           See systemd.unit(5) for details about unit names and
           Description=.

           Added in version 243.

       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.

           Added in version 212.

RESOURCE MANAGEMENT         top

       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.

           Added in version 198.

       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).

           Added in version 198.

       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).

           Added in version 243.

       NUMAMask=
           Configures the NUMA node mask that will be associated with the
           selected NUMA policy. Note that default and local NUMA
           policies do not 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).

           Added in version 243.

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

           DefaultCPUAccounting= defaults to yes when running on kernel
           ≥4.15, and no on older versions.  DefaultMemoryAccounting=
           defaults to yes.  DefaultTasksAccounting= defaults to yes. The
           other settings default to no.

           Added in version 211.

       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. 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.

           Added in version 228.

       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 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.

           Most of these settings are unset, which means the resource
           limits are inherited from the kernel or, if invoked in a
           container, from the container manager. However, the following
           have defaults:

           •   DefaultLimitNOFILE= defaults to 1024:524288.

           •   DefaultLimitMEMLOCK= defaults to 8M.

           •   DefaultLimitCORE= does not have a default but it is worth
               mentioning that RLIMIT_CORE is set to "infinity" by PID 1
               which is inherited by its children.

           Note that the service manager internally in PID 1 bumps
           RLIMIT_NOFILE and RLIMIT_MEMLOCK to higher values, however the
           limit is reverted to the mentioned defaults for all child
           processes forked off.

           Added in version 198.

       DefaultOOMPolicy=
           Configure the default policy for reacting to processes being
           killed by the Linux Out-Of-Memory (OOM) killer or
           systemd-oomd. 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.

           Added in version 243.

       DefaultOOMScoreAdjust=
           Configures the default OOM score adjustments of processes run
           by the service manager. This defaults to unset (meaning the
           forked off processes inherit the service manager's OOM score
           adjustment value), except if the service manager is run for an
           unprivileged user, in which case this defaults to the service
           manager's OOM adjustment value plus 100 (this makes service
           processes slightly more likely to be killed under memory
           pressure than the manager itself). This may be used to pick a
           global default for the per-unit OOMScoreAdjust= setting. See
           systemd.exec(5) for details. Note that this setting has no
           effect on the OOM score adjustment value of the service
           manager process itself, it retains the original value set
           during its invocation.

           Added in version 250.

       DefaultMemoryPressureWatch=, DefaultMemoryPressureThresholdSec=
           Configures the default settings for the per-unit
           MemoryPressureWatch= and MemoryPressureThresholdSec= settings.
           See systemd.resource-control(5) for details. Defaults to
           "auto" and "200ms", respectively. This also sets the memory
           pressure monitoring threshold for the service manager itself.

           Added in version 254.

HARDWARE WATCHDOG         top

       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"), or the special
           strings "off" or "default". If set to "off" (alternatively:
           "0") the watchdog logic is disabled: no watchdog device is
           opened, configured, or pinged. If set to the special string
           "default" the watchdog is opened and pinged in regular
           intervals, but the timeout is not changed from the default. If
           set to any other time value the watchdog timeout is configured
           to the specified value (or a value close to it, depending on
           hardware capabilities).

           If RuntimeWatchdogSec= is set to a non-zero value, the
           watchdog hardware (/dev/watchdog0 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.

           Added in version 198.

       RuntimeWatchdogPreSec=
           Configure the hardware watchdog device pre-timeout value.
           Takes a timeout value in seconds (or in other time units
           similar to RuntimeWatchdogSec=). A watchdog pre-timeout is a
           notification generated by the watchdog before the watchdog
           reset might occur in the event the watchdog has not been
           serviced. This notification is handled by the kernel and can
           be configured to take an action (i.e. generate a kernel panic)
           using RuntimeWatchdogPreGovernor=. Not all watchdog hardware
           or drivers support generating a pre-timeout and depending on
           the state of the system, the kernel may be unable to take the
           configured action before the watchdog reboot. The watchdog
           will be configured to generate the pre-timeout event at the
           amount of time specified by RuntimeWatchdogPreSec= before the
           runtime watchdog timeout (set by RuntimeWatchdogSec=). For
           example, if the we have RuntimeWatchdogSec=30 and
           RuntimeWatchdogPreSec=10, then the pre-timeout event will
           occur if the watchdog has not pinged for 20s (10s before the
           watchdog would fire). By default, RuntimeWatchdogPreSec=
           defaults to 0 (off). The value set for RuntimeWatchdogPreSec=
           must be smaller than the timeout value for
           RuntimeWatchdogSec=. This setting has no effect if a hardware
           watchdog is not available or the hardware watchdog does not
           support a pre-timeout and will be ignored by the kernel if the
           setting is greater than the actual watchdog timeout.

           Added in version 251.

       RuntimeWatchdogPreGovernor=
           Configure the action taken by the hardware watchdog device
           when the pre-timeout expires. The default action for the
           pre-timeout event depends on the kernel configuration, but it
           is usually to log a kernel message. For a list of valid
           actions available for a given watchdog device, check the
           content of the
           /sys/class/watchdog/watchdogX/pretimeout_available_governors
           file. Typically, available governor types are noop and panic.
           Availability, names and functionality might vary depending on
           the specific device driver in use. If the
           pretimeout_available_governors sysfs file is empty, the
           governor might be built as a kernel module and might need to
           be manually loaded (e.g.  pretimeout_noop.ko), or the watchdog
           device might not support pre-timeouts.

           Added in version 251.

       WatchdogDevice=
           Configure the hardware watchdog device that the runtime and
           shutdown watchdog timers will open and use. Defaults to
           /dev/watchdog0. This setting has no effect if a hardware
           watchdog is not available.

           Added in version 236.

SECURITY         top

       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.

           Added in version 198.

       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[2].

           Added in version 239.

       ProtectSystem=
           Takes a boolean argument or the string "auto". If set to true
           this will remount /usr/ read-only. If set to "auto" (the
           default) and running in an initrd equivalent to true,
           otherwise false. This implements a restricted subset of the
           per-unit setting of the same name, see systemd.exec(5) for
           details: currently, the "full" or "strict" values are not
           supported.

           Added in version 256.

       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.

           Added in version 209.

       DefaultSmackProcessLabel=
           Takes a SMACK64 security label as the argument. The process
           executed by a unit will be started under this label if
           SmackProcessLabel= is not set in the unit. See systemd.exec(5)
           for the details.

           If the value is "/", only labels specified with
           SmackProcessLabel= are assigned and the compile-time default
           is ignored.

           Added in version 252.

TIMEOUTS AND RATE LIMITS         top

       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). For non-service units,
           DefaultTimeoutStartSec= sets the default TimeoutSec= value.

           DefaultTimeoutStartSec= and DefaultTimeoutStopSec= default to
           90 s in the system manager and 90 s in the user manager.
           DefaultTimeoutAbortSec= is not set by default so that all
           units fall back to TimeoutStopSec=.  DefaultRestartSec=
           defaults to 100 ms.

           Added in version 209.

       DefaultDeviceTimeoutSec=
           Configures the default timeout for waiting for devices. It can
           be changed per device via the x-systemd.device-timeout= option
           in /etc/fstab and /etc/crypttab (see systemd.mount(5),
           crypttab(5)). Defaults to 90 s in the system manager and 90 s
           in the user manager.

           Added in version 252.

       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.

           Added in version 209.

       ReloadLimitIntervalSec=, ReloadLimitBurst=
           Rate limiting for daemon-reload and (since v256) daemon-reexec
           requests. The setting applies to both operations, but the rate
           limits are tracked separately. Defaults to unset, and any
           number of operations can be requested at any time.
           ReloadLimitIntervalSec= takes a value in seconds to configure
           the rate limit window, and ReloadLimitBurst= takes a positive
           integer to configure the maximum allowed number of operations
           within the configured time window.

           Added in version 253.

ENVIRONMENT         top

       ManagerEnvironment=
           Takes the same arguments as DefaultEnvironment=, see above.
           Sets environment variables for the manager process itself.
           These variables are inherited by processes spawned by user
           managers, but not the system manager - use DefaultEnvironment=
           for that. Note that these variables are merged into the
           existing environment block. In particular, in case of the
           system manager, this includes variables set by the kernel
           based on the kernel command line. As with DefaultEnvironment=,
           this environment block is internal, and changes are not
           reflected in the manager's /proc/PID/environ.

           Setting environment variables for the manager process may be
           useful to modify its behaviour. See Known Environment
           Variables[3] for a descriptions of some variables understood
           by systemd.

           Simple "%"-specifier expansion is supported, see below for a
           list of supported specifiers.

           Added in version 248.

       DefaultEnvironment=
           Configures environment variables passed to all executed
           processes. Takes a space-separated list of variable
           assignments. See environ(7) for details about environment
           variables.

           Simple "%"-specifier expansion is supported, see below for a
           list of supported specifiers.

           Example:

               DefaultEnvironment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6"

           Sets three variables "VAR1", "VAR2", "VAR3".

           Added in version 205.

SPECIFIERS         top

       Specifiers may be used in the DefaultEnvironment= and
       ManagerEnvironment= settings. The following expansions are
       understood:

       Table 1. Specifiers available
       ┌───────────┬──────────────────┬────────────────────────┐
       │ Specifier Meaning          Details                │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%a"      │ Architecture     │ A short string         │
       │           │                  │ identifying the        │
       │           │                  │ architecture of        │
       │           │                  │ the local system.      │
       │           │                  │ A string such as       │
       │           │                  │ x86, x86-64 or         │
       │           │                  │ arm64. See the         │
       │           │                  │ architectures          │
       │           │                  │ defined for            │
       │           │                  │ ConditionArchitecture= │
       │           │                  │ in systemd.unit(5)     │
       │           │                  │ for a full list.       │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%A"      │ Operating system │ The operating system   │
       │           │ image version    │ image version          │
       │           │                  │ identifier of the      │
       │           │                  │ running system, as     │
       │           │                  │ read from the          │
       │           │                  │ IMAGE_VERSION= field   │
       │           │                  │ of /etc/os-release. If │
       │           │                  │ not set, resolves to   │
       │           │                  │ an empty string. See   │
       │           │                  │ os-release(5) for more │
       │           │                  │ information.           │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%b"      │ Boot ID          │ The boot ID of the     │
       │           │                  │ running system,        │
       │           │                  │ formatted as string.   │
       │           │                  │ See random(4) for more │
       │           │                  │ information.           │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%B"      │ Operating system │ The operating system   │
       │           │ build ID         │ build identifier of    │
       │           │                  │ the running system, as │
       │           │                  │ read from the          │
       │           │                  │ BUILD_ID= field of     │
       │           │                  │ /etc/os-release. If    │
       │           │                  │ not set, resolves to   │
       │           │                  │ an empty string. See   │
       │           │                  │ os-release(5) for more │
       │           │                  │ information.           │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%H"      │ Host name        │ The hostname of the    │
       │           │                  │ running system.        │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%l"      │ Short host name  │ The hostname of the    │
       │           │                  │ running system,        │
       │           │                  │ truncated at the first │
       │           │                  │ dot to remove any      │
       │           │                  │ domain component.      │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%m"      │ Machine ID       │ The machine ID of the  │
       │           │                  │ running system,        │
       │           │                  │ formatted as string.   │
       │           │                  │ See machine-id(5) for  │
       │           │                  │ more information.      │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%M"      │ Operating system │ The operating system   │
       │           │ image identifier │ image identifier of    │
       │           │                  │ the running system, as │
       │           │                  │ read from the          │
       │           │                  │ IMAGE_ID= field of     │
       │           │                  │ /etc/os-release. If    │
       │           │                  │ not set, resolves to   │
       │           │                  │ an empty string. See   │
       │           │                  │ os-release(5) for more │
       │           │                  │ information.           │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%o"      │ Operating system │ The operating system   │
       │           │ ID               │ identifier of the      │
       │           │                  │ running system, as     │
       │           │                  │ read from the ID=      │
       │           │                  │ field of               │
       │           │                  │ /etc/os-release. See   │
       │           │                  │ os-release(5) for more │
       │           │                  │ information.           │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%v"      │ Kernel release   │ Identical to uname -r  │
       │           │                  │ output.                │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%w"      │ Operating system │ The operating system   │
       │           │ version ID       │ version identifier of  │
       │           │                  │ the running system, as │
       │           │                  │ read from the          │
       │           │                  │ VERSION_ID= field of   │
       │           │                  │ /etc/os-release. If    │
       │           │                  │ not set, resolves to   │
       │           │                  │ an empty string. See   │
       │           │                  │ os-release(5) for more │
       │           │                  │ information.           │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%W"      │ Operating system │ The operating system   │
       │           │ variant ID       │ variant identifier of  │
       │           │                  │ the running system, as │
       │           │                  │ read from the          │
       │           │                  │ VARIANT_ID= field of   │
       │           │                  │ /etc/os-release. If    │
       │           │                  │ not set, resolves to   │
       │           │                  │ an empty string. See   │
       │           │                  │ os-release(5) for more │
       │           │                  │ information.           │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%T"      │ Directory for    │ This is either /tmp or │
       │           │ temporary files  │ the path "$TMPDIR",    │
       │           │                  │ "$TEMP" or "$TMP" are  │
       │           │                  │ set to. (Note that the │
       │           │                  │ directory may be       │
       │           │                  │ specified without a    │
       │           │                  │ trailing slash.)       │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%V"      │ Directory for    │ This is either         │
       │           │ larger and       │ /var/tmp or the path   │
       │           │ persistent       │ "$TMPDIR", "$TEMP" or  │
       │           │ temporary files  │ "$TMP" are set to.     │
       │           │                  │ (Note that the         │
       │           │                  │ directory may be       │
       │           │                  │ specified without a    │
       │           │                  │ trailing slash.)       │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%h"      │ User home        │ This is the home       │
       │           │ directory        │ directory of the user  │
       │           │                  │ running the service    │
       │           │                  │ manager instance.      │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%u"      │ Username         │ This is the username   │
       │           │                  │ of the user running    │
       │           │                  │ the service manager    │
       │           │                  │ instance.              │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%U"      │ User id          │ This is the user id of │
       │           │                  │ the user running the   │
       │           │                  │ service manager        │
       │           │                  │ instance.              │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%g"      │ Primary group    │ This is the primary    │
       │           │                  │ group of the user      │
       │           │                  │ running the service    │
       │           │                  │ manager instance.      │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%G"      │ Primary group id │ This is the primary    │
       │           │                  │ group id of the user   │
       │           │                  │ running the service    │
       │           │                  │ manager instance.      │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%s"      │ User shell       │ This is the shell of   │
       │           │                  │ the user running the   │
       │           │                  │ service manager        │
       │           │                  │ instance.              │
       ├───────────┼──────────────────┼────────────────────────┤
       │ "%%"      │ Single percent   │ Use "%%" in place of   │
       │           │ sign             │ "%" to specify a       │
       │           │                  │ single percent sign.   │
       └───────────┴──────────────────┴────────────────────────┘

HISTORY         top

       systemd 252
           Option DefaultBlockIOAccounting= was deprecated. Please switch
           to the unified cgroup hierarchy.

           Added in version 252.

SEE ALSO         top

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

NOTES         top

        1. 💣💥🧨💥💥💣 Please note that those configuration files must
           be available at all times. If /usr/local/ is a separate
           partition, it may not be available during early boot, and must
           not be used for configuration.

        2. No New Privileges Flag
           https://docs.kernel.org/userspace-api/no_new_privs.html

        3. Known Environment Variables
           https://systemd.io/ENVIRONMENT

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have a
       bug report for this manual page, see
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
       This page was obtained from the project's upstream Git repository
       ⟨https://github.com/systemd/systemd.git⟩ on 2025-02-02.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2025-02-02.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there is
       a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

systemd 258~devel                                  SYSTEMD-SYSTEM.CONF(5)

Pages that refer to this page: run0(1)systemctl(1)systemd(1)journald.conf(5)logind.conf(5)systemd.exec(5)systemd.mount(5)systemd.resource-control(5)systemd.scope(5)systemd.service(5)systemd.socket(5)systemd.swap(5)systemd.timer(5)systemd.unit(5)kernel-command-line(7)systemd.directives(7)systemd.index(7)systemd.syntax(7)systemd-oomd.service(8)