NAME
systemd-system.conf, system.conf.d, systemd-user.conf, user.conf.d - System and session service manager configuration filesSYNOPSIS
/etc/systemd/system.conf, /etc/systemd/system.conf.d/*.conf, /run/systemd/system.conf.d/*.conf, /lib/systemd/system.conf.d/*.conf ~/.config/systemd/user.conf, /etc/systemd/user.conf, /etc/systemd/user.conf.d/*.conf, /run/systemd/user.conf.d/*.conf, /usr/lib/systemd/user.conf.d/*.confDESCRIPTION
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 (either in the home directory of the user, or if not found, under /etc/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
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 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 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: LogColor=, LogLevel=, LogLocation=, LogTarget=, LogTime=, DumpCore=yes, CrashChangeVT=no, CrashShell=no, CrashReboot=no, ShowStatus=yes, DefaultStandardOutput=journal, DefaultStandardError=inheritConfigures 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"), 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.
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.
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/watchdog
X/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.
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.
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 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=.
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.
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 90s.
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=
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:
Sets three variables "VAR1", "VAR2", "VAR3".
ManagerEnvironment=
DefaultEnvironment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6"
Takes the same arguments as
DefaultEnvironment=, see above. Sets environment variables just for the
manager process itself. In contrast to user managers, these variables are not
inherited by processes spawned by 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.
Setting environment variables for the manager process may be useful to modify
its behaviour. See ENVIRONMENT[2] for a descriptions of some variables
understood by systemd.
Simple "%"-specifier expansion is supported, see below for a list of
supported specifiers.
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. DefaultTasksAccounting= defaults to yes,
DefaultMemoryAccounting= to yes. DefaultCPUAccounting= defaults
to yes, but really has no effect 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. 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=,
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:
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.
DefaultOOMPolicy=
•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.
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.
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.
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.
SPECIFIERS
Specifiers may be used in the DefaultEnvironment= and ManagerEnvironment= settings. The following expansions are understood: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 image version | The operating system 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 build ID | The operating system 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 image identifier | The operating system 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 ID | The operating system 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 version ID | The operating system 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 variant ID | The operating system 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 temporary files | This is either /tmp or the path "$TMPDIR", "$TEMP" or "$TMP" are set to. (Note that the directory may be specified without a trailing slash.) |
"%V" | Directory for larger and persistent temporary files | This is either /var/tmp or the path "$TMPDIR", "$TEMP" or "$TMP" are set to. (Note that the directory may be specified without a trailing slash.) |
"%%" | Single percent sign | Use "%%" in place of "%" to specify a single percent sign. |
HISTORY
systemd 252Option DefaultBlockIOAccounting= was
deprecated. Please switch to the unified cgroup hierarchy.
SEE ALSO
systemd(1), systemd.directives(7), systemd.exec(5), systemd.service(5), environ(7), capabilities(7)NOTES
- 1.
- No New Privileges Flag
- 2.
- ENVIRONMENT
systemd 252 |