summaryrefslogtreecommitdiffstats
path: root/man/systemd-system.conf.xml
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--man/systemd-system.conf.xml619
1 files changed, 619 insertions, 0 deletions
diff --git a/man/systemd-system.conf.xml b/man/systemd-system.conf.xml
new file mode 100644
index 0000000..2bdfa1c
--- /dev/null
+++ b/man/systemd-system.conf.xml
@@ -0,0 +1,619 @@
+<?xml version='1.0'?>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
+ "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
+<!ENTITY % entities SYSTEM "custom-entities.ent" >
+%entities;
+]>
+<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
+
+<refentry id="systemd-system.conf"
+ xmlns:xi="http://www.w3.org/2001/XInclude">
+ <refentryinfo>
+ <title>systemd-system.conf</title>
+ <productname>systemd</productname>
+ </refentryinfo>
+
+ <refmeta>
+ <refentrytitle>systemd-system.conf</refentrytitle>
+ <manvolnum>5</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+ <refname>systemd-system.conf</refname>
+ <refname>system.conf.d</refname>
+ <refname>systemd-user.conf</refname>
+ <refname>user.conf.d</refname>
+ <refpurpose>System and session service manager configuration files</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <para><filename>/etc/systemd/system.conf</filename>,
+ <filename>/etc/systemd/system.conf.d/*.conf</filename>,
+ <filename>/run/systemd/system.conf.d/*.conf</filename>,
+ <filename>/usr/lib/systemd/system.conf.d/*.conf</filename></para>
+
+ <para><filename>~/.config/systemd/user.conf</filename>,
+ <filename>/etc/systemd/user.conf</filename>,
+ <filename>/etc/systemd/user.conf.d/*.conf</filename>,
+ <filename>/run/systemd/user.conf.d/*.conf</filename>,
+ <filename>/usr/lib/systemd/user.conf.d/*.conf</filename></para>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para>When run as a system instance, <command>systemd</command> interprets the configuration file
+ <filename>system.conf</filename> and the files in <filename>system.conf.d</filename> directories; when
+ run as a user instance, it interprets the configuration file <filename>user.conf</filename> (either in
+ the home directory of the user, or if not found, under <filename>/etc/systemd/</filename>) and the files
+ in <filename>user.conf.d</filename> directories. These configuration files contain a few settings
+ controlling basic manager operations.</para>
+
+ <para>See
+ <citerefentry><refentrytitle>systemd.syntax</refentrytitle><manvolnum>7</manvolnum></citerefentry> for a
+ general description of the syntax.</para>
+ </refsect1>
+
+ <xi:include href="standard-conf.xml" xpointer="main-conf" />
+
+ <refsect1>
+ <title>Options</title>
+
+ <para>All options are configured in the
+ [Manager] section:</para>
+
+ <variablelist class='config-directives'>
+
+ <varlistentry>
+ <term><varname>LogColor=</varname></term>
+ <term><varname>LogLevel=</varname></term>
+ <term><varname>LogLocation=</varname></term>
+ <term><varname>LogTarget=</varname></term>
+ <term><varname>LogTime=</varname></term>
+ <term><varname>DumpCore=yes</varname></term>
+ <term><varname>CrashChangeVT=no</varname></term>
+ <term><varname>CrashShell=no</varname></term>
+ <term><varname>CrashReboot=no</varname></term>
+ <term><varname>ShowStatus=yes</varname></term>
+ <term><varname>DefaultStandardOutput=journal</varname></term>
+ <term><varname>DefaultStandardError=inherit</varname></term>
+
+ <listitem><para>Configures various parameters of basic manager operation. These options may be overridden by
+ the respective process and kernel command line arguments. See
+ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> for
+ details.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>CtrlAltDelBurstAction=</varname></term>
+
+ <listitem><para>Defines what action will be performed
+ if user presses Ctrl-Alt-Delete more than 7 times in 2s.
+ Can be set to <literal>reboot-force</literal>, <literal>poweroff-force</literal>,
+ <literal>reboot-immediate</literal>, <literal>poweroff-immediate</literal>
+ or disabled with <literal>none</literal>. Defaults to
+ <literal>reboot-force</literal>.
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>CPUAffinity=</varname></term>
+
+ <listitem><para>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
+ <varname>CPUAffinity=</varname> setting in unit files, see
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>NUMAPolicy=</varname></term>
+
+ <listitem><para>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
+ <varname>NUMAPolicy=</varname> setting in unit files, see
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>NUMAMask=</varname></term>
+
+ <listitem><para>Configures the NUMA node mask that will be associated with the selected NUMA policy. Note that
+ <option>default</option> and <option>local</option> NUMA policies don't require explicit NUMA node mask and
+ value of the option can be empty. Similarly to <varname>NUMAPolicy=</varname>, value can be overridden
+ by individual services in unit files, see
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>RuntimeWatchdogSec=</varname></term>
+ <term><varname>RebootWatchdogSec=</varname></term>
+ <term><varname>KExecWatchdogSec=</varname></term>
+
+ <listitem><para>Configure the hardware watchdog at runtime and at reboot. Takes a timeout value in
+ seconds (or in other time units if suffixed with <literal>ms</literal>, <literal>min</literal>,
+ <literal>h</literal>, <literal>d</literal>, <literal>w</literal>), or the special strings
+ <literal>off</literal> or <literal>default</literal>. If set to <literal>off</literal>
+ (alternatively: <literal>0</literal>) the watchdog logic is disabled: no watchdog device is opened,
+ configured, or pinged. If set to the special string <literal>default</literal> 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).</para>
+
+ <para>If <varname>RuntimeWatchdogSec=</varname> is set to a non-zero value, the watchdog hardware
+ (<filename>/dev/watchdog0</filename> or the path specified with <varname>WatchdogDevice=</varname> or
+ the kernel option <varname>systemd.watchdog-device=</varname>) 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.</para>
+
+ <para><varname>RebootWatchdogSec=</varname> 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 <varname>RebootWatchdogSec=</varname> 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
+ <filename>systemd-shutdown</filename> binary, see system
+ <citerefentry><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
+ details. During the first phase of the shutdown operation the system and service manager remains
+ running and hence <varname>RuntimeWatchdogSec=</varname> is still honoured. In order to define a
+ timeout on this first phase of system shutdown, configure <varname>JobTimeoutSec=</varname> and
+ <varname>JobTimeoutAction=</varname> in the [Unit] section of the
+ <filename>shutdown.target</filename> unit. By default <varname>RuntimeWatchdogSec=</varname> defaults
+ to 0 (off), and <varname>RebootWatchdogSec=</varname> to 10min.</para>
+
+ <para><varname>KExecWatchdogSec=</varname> 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
+ <varname>RuntimeWatchdogSec=</varname> is also enabled at the same time. For this reason it is
+ recommended to enable <varname>KExecWatchdogSec=</varname> only if
+ <varname>RuntimeWatchdogSec=</varname> is also enabled.</para>
+
+ <para>These settings have no effect if a hardware watchdog is not available.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>RuntimeWatchdogPreSec=</varname></term>
+
+ <listitem><para>Configure the hardware watchdog device pre-timeout value.
+ Takes a timeout value in seconds (or in other time units similar to
+ <varname>RuntimeWatchdogSec=</varname>). 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 <varname>RuntimeWatchdogPreGovernor=</varname>.
+ 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
+ <varname>RuntimeWatchdogPreSec=</varname> before the runtime watchdog timeout
+ (set by <varname>RuntimeWatchdogSec=</varname>). For example, if the we have
+ <varname>RuntimeWatchdogSec=30</varname> and
+ <varname>RuntimeWatchdogPreSec=10</varname>, then the pre-timeout event
+ will occur if the watchdog has not pinged for 20s (10s before the
+ watchdog would fire). By default, <varname>RuntimeWatchdogPreSec=</varname>
+ defaults to 0 (off). The value set for <varname>RuntimeWatchdogPreSec=</varname>
+ must be smaller than the timeout value for <varname>RuntimeWatchdogSec=</varname>.
+ 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.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>RuntimeWatchdogPreGovernor=</varname></term>
+
+ <listitem><para>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
+ <filename>/sys/class/watchdog/watchdog<replaceable>X</replaceable>/pretimeout_available_governors</filename>
+ file. Typically, available governor types are <varname>noop</varname> and <varname>panic</varname>.
+ Availability, names and functionality might vary depending on the specific device driver
+ in use. If the <filename>pretimeout_available_governors</filename> sysfs file is empty,
+ the governor might be built as a kernel module and might need to be manually loaded
+ (e.g. <varname>pretimeout_noop.ko</varname>), or the watchdog device might not support
+ pre-timeouts.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>WatchdogDevice=</varname></term>
+
+ <listitem><para>Configure the hardware watchdog device that the
+ runtime and shutdown watchdog timers will open and use. Defaults
+ to <filename>/dev/watchdog0</filename>. This setting has no
+ effect if a hardware watchdog is not available.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>CapabilityBoundingSet=</varname></term>
+
+ <listitem><para>Controls which capabilities to include in the
+ capability bounding set for PID 1 and its children. See
+ <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ for details. Takes a whitespace-separated list of capability
+ names as read by
+ <citerefentry project='mankier'><refentrytitle>cap_from_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+ 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 <varname>CapabilityBoundingSet=</varname> directive
+ for units, but note that capabilities dropped for PID 1 cannot
+ be regained in individual units, they are lost for
+ good.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>NoNewPrivileges=</varname></term>
+
+ <listitem><para>Takes a boolean argument. If true, ensures that PID 1
+ and all its children can never gain new privileges through
+ <citerefentry project='man-pages'><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+ (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 <ulink url="https://docs.kernel.org/userspace-api/no_new_privs.html">No New Privileges Flag</ulink>.
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>SystemCallArchitectures=</varname></term>
+
+ <listitem><para>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
+ <varname>SystemCallArchitectures=</varname> setting of unit
+ files, see
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ 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
+ <literal>x86</literal>, <literal>x86-64</literal>,
+ <literal>x32</literal>, <literal>arm</literal> and the special
+ identifier <literal>native</literal>. 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 <literal>native</literal> 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.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>TimerSlackNSec=</varname></term>
+
+ <listitem><para>Sets the timer slack in nanoseconds for PID 1,
+ which is inherited by all executed processes, unless
+ overridden individually, for example with the
+ <varname>TimerSlackNSec=</varname> setting in service units
+ (for details see
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
+ The timer slack controls the accuracy of wake-ups triggered by
+ system timers. See
+ <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+ 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.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>StatusUnitFormat=</varname></term>
+
+ <listitem><para>Takes <option>name</option>, <option>description</option> or
+ <option>combined</option> as the value. If <option>name</option>, the system manager will use unit
+ names in status messages (e.g. <literal>systemd-journald.service</literal>), instead of the longer
+ and more informative descriptions set with <varname>Description=</varname> (e.g. <literal>Journal
+ Logging Service</literal>). If <option>combined</option>, the system manager will use both unit names
+ and descriptions in status messages (e.g. <literal>systemd-journald.service - Journal Logging
+ Service</literal>).</para>
+
+ <para>See
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
+ details about unit names and <varname>Description=</varname>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>DefaultTimerAccuracySec=</varname></term>
+
+ <listitem><para>Sets the default accuracy of timer units. This
+ controls the global default for the
+ <varname>AccuracySec=</varname> setting of timer units, see
+ <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details. <varname>AccuracySec=</varname> 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
+ <varname>TimerSlackNSec=</varname> above.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>DefaultTimeoutStartSec=</varname></term>
+ <term><varname>DefaultTimeoutStopSec=</varname></term>
+ <term><varname>DefaultTimeoutAbortSec=</varname></term>
+ <term><varname>DefaultRestartSec=</varname></term>
+
+ <listitem><para>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
+ <varname>TimeoutStartSec=</varname>,
+ <varname>TimeoutStopSec=</varname>,
+ <varname>TimeoutAbortSec=</varname> and
+ <varname>RestartSec=</varname> (for services, see
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details on the per-unit settings). Disabled by default, when
+ service with <varname>Type=oneshot</varname> is used.
+ For non-service units,
+ <varname>DefaultTimeoutStartSec=</varname> sets the default
+ <varname>TimeoutSec=</varname>
+ value. <varname>DefaultTimeoutStartSec=</varname> and
+ <varname>DefaultTimeoutStopSec=</varname> default to
+ 90s. <varname>DefaultTimeoutAbortSec=</varname> is not set by default
+ so that all units fall back to <varname>TimeoutStopSec=</varname>.
+ <varname>DefaultRestartSec=</varname> defaults to
+ 100ms.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>DefaultDeviceTimeoutSec=</varname></term>
+
+ <listitem><para>Configures the default timeout for waiting for devices. It can be changed per
+ device via the <varname>x-systemd.device-timeout=</varname> option in <filename>/etc/fstab</filename>
+ and <filename>/etc/crypttab</filename> (see
+ <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
+ Defaults to 90s.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>DefaultStartLimitIntervalSec=</varname></term>
+ <term><varname>DefaultStartLimitBurst=</varname></term>
+
+ <listitem><para>Configure the default unit start rate
+ limiting, as configured per-service by
+ <varname>StartLimitIntervalSec=</varname> and
+ <varname>StartLimitBurst=</varname>. See
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details on the per-service settings.
+ <varname>DefaultStartLimitIntervalSec=</varname> defaults to
+ 10s. <varname>DefaultStartLimitBurst=</varname> defaults to
+ 5.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>DefaultEnvironment=</varname></term>
+
+ <listitem><para>Configures environment variables passed to all executed processes. Takes a
+ space-separated list of variable assignments. See <citerefentry
+ project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
+ details about environment variables.</para>
+
+ <para>Simple <literal>%</literal>-specifier expansion is supported, see below for a list of supported
+ specifiers.</para>
+
+ <para>Example:
+
+ <programlisting>DefaultEnvironment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6"</programlisting>
+
+ Sets three variables
+ <literal>VAR1</literal>,
+ <literal>VAR2</literal>,
+ <literal>VAR3</literal>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>ManagerEnvironment=</varname></term>
+
+ <listitem><para>Takes the same arguments as <varname>DefaultEnvironment=</varname>, 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 <varname>DefaultEnvironment=</varname>
+ 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.</para>
+
+ <para>Setting environment variables for the manager process may be useful to modify its behaviour.
+ See <ulink url="https://systemd.io/ENVIRONMENT">ENVIRONMENT</ulink> for a descriptions of some
+ variables understood by <command>systemd</command>.</para>
+
+ <para>Simple <literal>%</literal>-specifier expansion is supported, see below for a list of supported
+ specifiers.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>DefaultCPUAccounting=</varname></term>
+ <term><varname>DefaultMemoryAccounting=</varname></term>
+ <term><varname>DefaultTasksAccounting=</varname></term>
+ <term><varname>DefaultIOAccounting=</varname></term>
+ <term><varname>DefaultIPAccounting=</varname></term>
+
+ <listitem><para>Configure the default resource accounting settings, as configured per-unit by
+ <varname>CPUAccounting=</varname>, <varname>MemoryAccounting=</varname>,
+ <varname>TasksAccounting=</varname>, <varname>IOAccounting=</varname> and
+ <varname>IPAccounting=</varname>. See
+ <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details on the per-unit settings. <varname>DefaultTasksAccounting=</varname> defaults to yes,
+ <varname>DefaultMemoryAccounting=</varname> to &MEMORY_ACCOUNTING_DEFAULT;.
+ <varname>DefaultCPUAccounting=</varname> defaults to yes, but really has no effect if enabling CPU
+ accounting doesn't require the <option>cpu</option> 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.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>DefaultTasksMax=</varname></term>
+
+ <listitem><para>Configure the default value for the per-unit <varname>TasksMax=</varname> setting. See
+ <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ 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 <varname>kernel.pid_max=</varname>, <varname>kernel.threads-max=</varname>
+ and root cgroup <varname>pids.max</varname>.
+ Kernel has a default value for <varname>kernel.pid_max=</varname> and an algorithm of counting in case of more than 32 cores.
+ For example with the default <varname>kernel.pid_max=</varname>, <varname>DefaultTasksMax=</varname> defaults to 4915,
+ but might be greater in other systems or smaller in OS containers.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>DefaultLimitCPU=</varname></term>
+ <term><varname>DefaultLimitFSIZE=</varname></term>
+ <term><varname>DefaultLimitDATA=</varname></term>
+ <term><varname>DefaultLimitSTACK=</varname></term>
+ <term><varname>DefaultLimitCORE=</varname></term>
+ <term><varname>DefaultLimitRSS=</varname></term>
+ <term><varname>DefaultLimitNOFILE=</varname></term>
+ <term><varname>DefaultLimitAS=</varname></term>
+ <term><varname>DefaultLimitNPROC=</varname></term>
+ <term><varname>DefaultLimitMEMLOCK=</varname></term>
+ <term><varname>DefaultLimitLOCKS=</varname></term>
+ <term><varname>DefaultLimitSIGPENDING=</varname></term>
+ <term><varname>DefaultLimitMSGQUEUE=</varname></term>
+ <term><varname>DefaultLimitNICE=</varname></term>
+ <term><varname>DefaultLimitRTPRIO=</varname></term>
+ <term><varname>DefaultLimitRTTIME=</varname></term>
+
+ <listitem><para>These settings control various default resource limits for processes executed by
+ units. See
+ <citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry> for
+ details. These settings may be overridden in individual units using the corresponding
+ <varname>LimitXXX=</varname> directives and they accept the same parameter syntax,
+ see <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ 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.</para>
+
+ <para>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:</para>
+ <itemizedlist>
+ <listitem><para><varname>DefaultLimitNOFILE=</varname> defaults to 1024:&HIGH_RLIMIT_NOFILE;.
+ </para></listitem>
+
+ <listitem><para><varname>DefaultLimitMEMLOCK=</varname> defaults to 8M.</para></listitem>
+
+ <listitem><para><varname>DefaultLimitCORE=</varname> does not have a default but it is worth mentioning that
+ <varname>RLIMIT_CORE</varname> is set to <literal>infinity</literal> by PID 1 which is inherited by its
+ children.</para></listitem>
+ </itemizedlist>
+
+ <para>Note that the service manager internally in PID 1 bumps <varname>RLIMIT_NOFILE</varname> and
+ <varname>RLIMIT_MEMLOCK</varname> to higher values, however the limit is reverted to the mentioned
+ defaults for all child processes forked off.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>DefaultOOMPolicy=</varname></term>
+
+ <listitem><para>Configure the default policy for reacting to processes being killed by the Linux
+ Out-Of-Memory (OOM) killer or <command>systemd-oomd</command>. This may be used to pick a global default for the per-unit
+ <varname>OOMPolicy=</varname> setting. See
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details. Note that this default is not used for services that have <varname>Delegate=</varname>
+ turned on.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>DefaultOOMScoreAdjust=</varname></term>
+
+ <listitem><para>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 <varname>OOMScoreAdjust=</varname> setting. See
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> 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.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>DefaultSmackProcessLabel=</varname></term>
+
+ <listitem><para>Takes a <option>SMACK64</option> security label as the argument. The process executed
+ by a unit will be started under this label if <varname>SmackProcessLabel=</varname> is not set in the
+ unit. See <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for the details.</para>
+
+ <para>If the value is <literal>/</literal>, only labels specified with <varname>SmackProcessLabel=</varname>
+ are assigned and the compile-time default is ignored.</para></listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Specifiers</title>
+
+ <para>Specifiers may be used in the <varname>DefaultEnvironment=</varname> and
+ <varname>ManagerEnvironment=</varname> settings. The following expansions are understood:</para>
+ <table class='specifiers'>
+ <title>Specifiers available</title>
+ <tgroup cols='3' align='left' colsep='1' rowsep='1'>
+ <colspec colname="spec" />
+ <colspec colname="mean" />
+ <colspec colname="detail" />
+ <thead>
+ <row>
+ <entry>Specifier</entry>
+ <entry>Meaning</entry>
+ <entry>Details</entry>
+ </row>
+ </thead>
+ <tbody>
+ <xi:include href="standard-specifiers.xml" xpointer="a"/>
+ <xi:include href="standard-specifiers.xml" xpointer="A"/>
+ <xi:include href="standard-specifiers.xml" xpointer="b"/>
+ <xi:include href="standard-specifiers.xml" xpointer="B"/>
+ <xi:include href="standard-specifiers.xml" xpointer="H"/>
+ <xi:include href="standard-specifiers.xml" xpointer="l"/>
+ <xi:include href="standard-specifiers.xml" xpointer="m"/>
+ <xi:include href="standard-specifiers.xml" xpointer="M"/>
+ <xi:include href="standard-specifiers.xml" xpointer="o"/>
+ <xi:include href="standard-specifiers.xml" xpointer="v"/>
+ <xi:include href="standard-specifiers.xml" xpointer="w"/>
+ <xi:include href="standard-specifiers.xml" xpointer="W"/>
+ <xi:include href="standard-specifiers.xml" xpointer="T"/>
+ <xi:include href="standard-specifiers.xml" xpointer="V"/>
+ <xi:include href="standard-specifiers.xml" xpointer="percent"/>
+ </tbody>
+ </tgroup>
+ </table>
+ </refsect1>
+
+ <refsect1>
+ <title>History</title>
+
+ <variablelist>
+ <varlistentry>
+ <term>systemd 252</term>
+ <listitem><para>Option <varname>DefaultBlockIOAccounting=</varname> was deprecated. Please switch
+ to the unified cgroup hierarchy.</para></listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>See Also</title>
+ <para>
+ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ </para>
+ </refsect1>
+
+</refentry>