"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
+ SPDX-License-Identifier: LGPL-2.1+
+
This file is part of systemd.
Copyright 2010 Lennart Poettering
<refsynopsisdiv>
<cmdsynopsis>
- <command>systemd <arg choice="opt" rep="repeat">OPTIONS</arg></command>
+ <command>systemd</command>
+ <arg choice="opt" rep="repeat">OPTIONS</arg>
</cmdsynopsis>
<cmdsynopsis>
- <command>init <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="req">COMMAND</arg></command>
+ <command>init</command>
+ <arg choice="opt" rep="repeat">OPTIONS</arg>
+ <arg choice="req">COMMAND</arg>
</cmdsynopsis>
</refsynopsisdiv>
user instance. This setting may also be enabled during boot,
on the kernel command line via the
<varname>systemd.crash_vt=</varname> option, see
+ <!-- FIXME: there is no crash_vt command line option? -->
below.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--show-status=</option></term>
- <listitem><para>Show terse service status information while
- booting. This switch has no effect when run as user instance.
- Takes a boolean argument which may be omitted which is
- interpreted as <option>true</option>.</para></listitem>
+ <listitem><para>Takes a boolean argument or the special value <constant>auto</constant>. If on, terse unit
+ status information is shown on the console during boot-up and shutdown. If off, no such status information is
+ shown. If set to <constant>auto</constant> behavior is similar to off, except that it is automatically switched
+ to on, as soon as the first unit failure or significant boot delay is encountered. This switch has no effect
+ when invoked as user instance. If specified, overrides both the kernel command line setting
+ <varname>systemd.show_status=</varname> (see below) and the configuration file option
+ <option>ShowStatus=</option>, see
+ <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--log-target=</option></term>
<title>Concepts</title>
<para>systemd provides a dependency system between various
- entities called "units" of 12 different types. Units encapsulate
+ entities called "units" of 11 different types. Units encapsulate
various objects that are relevant for system boot-up and
maintenance. The majority of units are configured in unit
configuration files, whose syntax and basic set of options is
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
however some are created automatically from other configuration,
dynamically from system state or programmatically at runtime.
- Units may be "active" (meaning started, bound, plugged in, ...,
+ Units may be "active" (meaning started, bound, plugged in, …,
depending on the unit type, see below), or "inactive" (meaning
- stopped, unbound, unplugged, ...), as well as in the process of
+ stopped, unbound, unplugged, …), as well as in the process of
being activated or deactivated, i.e. between the two states (these
states are called "activating", "deactivating"). A special
"failed" state is available as well, which is very similar to
<para>Note that some but not all interfaces provided
by systemd are covered by the
- <ulink url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface
+ <ulink url="https://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface
Stability Promise</ulink>.</para>
<para>Units may be generated dynamically at boot and system
<para>Systems which invoke systemd in a container or initrd
environment should implement the
- <ulink url="http://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container Interface</ulink> or
- <ulink url="http://www.freedesktop.org/wiki/Software/systemd/InitrdInterface">initrd Interface</ulink>
+ <ulink url="https://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container Interface</ulink> or
+ <ulink url="https://www.freedesktop.org/wiki/Software/systemd/InitrdInterface">initrd Interface</ulink>
specifications, respectively.</para>
</refsect1>
<para>systemd user managers will start the
<filename>exit.target</filename> unit when this signal is
received. This is mostly equivalent to <command>systemctl
- --user start exit.target</command>.</para></listitem>
+ --user start exit.target
+ --job-mode=replace-irreversible</command>.</para></listitem>
</varlistentry>
<varlistentry>
<listitem><para>Upon receiving this signal the systemd system
manager will start the
<filename>ctrl-alt-del.target</filename> unit. This is mostly
- equivalent to <command>systemctl start
- ctl-alt-del.target</command>. If this signal is received more
- than 7 times per 2s, an immediate reboot is triggered.
- Note that pressing Ctrl-Alt-Del on the console will trigger
- this signal. Hence, if a reboot is hanging, pressing
- Ctrl-Alt-Del more than 7 times in 2s is a relatively safe way
- to trigger an immediate reboot.</para>
+ equivalent to <command>systemctl start ctl-alt-del.target
+ --job-mode=replace-irreversible</command>. If this signal is
+ received more than 7 times per 2s, an immediate reboot is
+ triggered. Note that pressing Ctrl-Alt-Del on the console
+ will trigger this signal. Hence, if a reboot is hanging,
+ pressing Ctrl-Alt-Del more than 7 times in 2s is a relatively
+ safe way to trigger an immediate reboot.</para>
<para>systemd user managers treat this signal the same way as
<constant>SIGTERM</constant>.</para></listitem>
<listitem><para>Enters default mode, starts the
<filename>default.target</filename> unit. This is mostly
- equivalent to <command>systemctl start
+ equivalent to <command>systemctl isolate
default.target</command>.</para></listitem>
</varlistentry>
<listitem><para>Halts the machine, starts the
<filename>halt.target</filename> unit. This is mostly
- equivalent to <command>systemctl start
- halt.target</command>.</para></listitem>
+ equivalent to <command>systemctl start halt.target
+ --job-mode=replace-irreversible</command>.</para>
+ </listitem>
</varlistentry>
<varlistentry>
<listitem><para>Powers off the machine, starts the
<filename>poweroff.target</filename> unit. This is mostly
- equivalent to <command>systemctl start
- poweroff.target</command>.</para></listitem>
+ equivalent to <command>systemctl start poweroff.target
+ --job-mode=replace-irreversible</command>.</para>
+ </listitem>
</varlistentry>
<varlistentry>
<listitem><para>Reboots the machine, starts the
<filename>reboot.target</filename> unit. This is mostly
- equivalent to <command>systemctl start
- reboot.target</command>.</para></listitem>
+ equivalent to <command>systemctl start reboot.target
+ --job-mode=replace-irreversible</command>.</para>
+ </listitem>
</varlistentry>
<varlistentry>
<listitem><para>Reboots the machine via kexec, starts the
<filename>kexec.target</filename> unit. This is mostly
- equivalent to <command>systemctl start
- kexec.target</command>.</para></listitem>
+ equivalent to <command>systemctl start kexec.target
+ --job-mode=replace-irreversible</command>.</para>
+ </listitem>
</varlistentry>
<varlistentry>
<term><constant>SIGRTMIN+27</constant></term>
<term><constant>SIGRTMIN+28</constant></term>
- <listitem><para>Sets the log level to
+ <listitem><para>Sets the log target to
<literal>journal-or-kmsg</literal> (or
<literal>console</literal> on
<constant>SIGRTMIN+27</constant>, <literal>kmsg</literal> on
<varlistentry>
<term><varname>$SYSTEMD_COLORS</varname></term>
- <listitem><para>Controls whether colorized output should be generated.
- </para></listitem>
+ <listitem><para>The value must be a boolean. Controls whether colorized output should be
+ generated. This can be specified to override the decision that <command>systemd</command>
+ makes based on <varname>$TERM</varname> and what the console is connected to.</para>
+ </listitem>
</varlistentry>
<varlistentry>
<listitem><para>Set by systemd for supervised processes during
socket-based activation. See
<citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- for more information. </para></listitem>
+ for more information.</para></listitem>
</varlistentry>
<varlistentry>
<listitem><para>Set by systemd for supervised processes for
status and start-up completion notification. See
<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- for more information. </para></listitem>
+ for more information.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
</varlistentry>
<varlistentry>
- <term><varname>systemd.dump_core=</varname></term>
+ <term><varname>systemd.dump_core</varname></term>
- <listitem><para>Takes a boolean argument. If
- <option>yes</option>, the systemd manager (PID 1) dumps core
- when it crashes. Otherwise, no core dump is created. Defaults
- to <option>yes</option>.</para></listitem>
+ <listitem><para>Takes a boolean argument or enables the option if specified
+ without an argument. If enabled, the systemd manager (PID 1) dumps core when
+ it crashes. Otherwise, no core dump is created. Defaults to enabled.</para>
+ </listitem>
</varlistentry>
<varlistentry>
- <term><varname>systemd.crash_chvt=</varname></term>
+ <term><varname>systemd.crash_chvt</varname></term>
- <listitem><para>Takes a positive integer, or a boolean
- argument. If a positive integer (in the range 1–63) is
- specified, the system manager (PID 1) will activate the specified
- virtual terminal (VT) when it crashes. Defaults to
- <constant>no</constant>, meaning that no such switch is
- attempted. If set to <constant>yes</constant>, the VT the
- kernel messages are written to is selected.</para></listitem>
+ <listitem><para>Takes a positive integer, or a boolean argument. Can be also
+ specified without an argument, with the same effect as a positive boolean. If
+ a positive integer (in the range 1–63) is specified, the system manager (PID
+ 1) will activate the specified virtual terminal (VT) when it
+ crashes. Defaults to disabled, meaning that no such switch is attempted. If
+ set to enabled, the VT the kernel messages are written to is selected.
+ </para></listitem>
</varlistentry>
<varlistentry>
- <term><varname>systemd.crash_shell=</varname></term>
+ <term><varname>systemd.crash_shell</varname></term>
- <listitem><para>Takes a boolean argument. If
- <option>yes</option>, the system manager (PID 1) spawns a
- shell when it crashes, after a 10s delay. Otherwise, no shell
- is spawned. Defaults to <option>no</option>, for security
- reasons, as the shell is not protected by password
+ <listitem><para>Takes a boolean argument or enables the option if specified
+ without an argument. If enabled, the system manager (PID 1) spawns a shell
+ when it crashes, after a 10s delay. Otherwise, no shell is spawned. Defaults
+ to disabled, for security reasons, as the shell is not protected by password
authentication.</para></listitem>
</varlistentry>
<varlistentry>
- <term><varname>systemd.crash_reboot=</varname></term>
+ <term><varname>systemd.crash_reboot</varname></term>
- <listitem><para>Takes a boolean argument. If
- <option>yes</option>, the system manager (PID 1) will reboot
- the machine automatically when it crashes, after a 10s delay.
- Otherwise, the system will hang indefinitely. Defaults to
- <option>no</option>, in order to avoid a reboot loop. If
- combined with <varname>systemd.crash_shell=</varname>, the
+ <listitem><para>Takes a boolean argument or enables the option if specified
+ without an argument. If enabled, the system manager (PID 1) will reboot the
+ machine automatically when it crashes, after a 10s delay. Otherwise, the
+ system will hang indefinitely. Defaults to disabled, in order to avoid a
+ reboot loop. If combined with <varname>systemd.crash_shell</varname>, the
system is rebooted after the shell exits.</para></listitem>
</varlistentry>
<varlistentry>
- <term><varname>systemd.confirm_spawn=</varname></term>
+ <term><varname>systemd.confirm_spawn</varname></term>
- <listitem><para>Takes a boolean argument. If
- <option>yes</option>, the system manager (PID 1) asks for
- confirmation when spawning processes. Defaults to
- <option>no</option>.</para></listitem>
+ <listitem><para>Takes a boolean argument or a path to the virtual console
+ where the confirmation messages should be emitted. Can be also specified
+ without an argument, with the same effect as a positive boolean. If enabled,
+ the system manager (PID 1) asks for confirmation when spawning processes
+ using <option>/dev/console</option>. If a path or a console name (such as
+ <literal>ttyS0</literal>) is provided, the virtual console pointed to by this
+ path or described by the give name will be used instead. Defaults to disabled.
+ </para></listitem>
</varlistentry>
<varlistentry>
- <term><varname>systemd.show_status=</varname></term>
+ <term><varname>systemd.show_status</varname></term>
<listitem><para>Takes a boolean argument or the constant
- <constant>auto</constant>. If <option>yes</option>, the
- systemd manager (PID 1) shows terse service status updates on
- the console during bootup. <constant>auto</constant> behaves
- like <option>false</option> until a service fails or there is
- a significant delay in boot. Defaults to
- <option>yes</option>, unless <option>quiet</option> is passed
- as kernel command line option, in which case it defaults to
- <constant>auto</constant>.</para></listitem>
+ <constant>auto</constant>. Can be also specified without an argument, with
+ the same effect as a positive boolean. If enabled, the systemd manager (PID
+ 1) shows terse service status updates on the console during bootup.
+ <constant>auto</constant> behaves like <option>false</option> until a unit
+ fails or there is a significant delay in boot. Defaults to enabled, unless
+ <option>quiet</option> is passed as kernel command line option, in which case
+ it defaults to <constant>auto</constant>. If specified overrides the system
+ manager configuration file option <option>ShowStatus=</option>, see
+ <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+ However, the process command line option <option>--show-status=</option>
+ takes precedence over both this kernel command line option and the
+ configuration file option.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>systemd.log_target=</varname></term>
<term><varname>systemd.log_level=</varname></term>
- <term><varname>systemd.log_color=</varname></term>
<term><varname>systemd.log_location=</varname></term>
+ <term><varname>systemd.log_color</varname></term>
- <listitem><para>Controls log output, with the same effect as
- the <varname>$SYSTEMD_LOG_TARGET</varname>,
+ <listitem><para>Controls log output, with the same effect as the
+ <varname>$SYSTEMD_LOG_TARGET</varname>,
<varname>$SYSTEMD_LOG_LEVEL</varname>,
- <varname>$SYSTEMD_LOG_COLOR</varname>,
- <varname>$SYSTEMD_LOG_LOCATION</varname> environment variables
- described above.</para></listitem>
+ <varname>$SYSTEMD_LOG_LOCATION</varname>,
+ <varname>$SYSTEMD_LOG_COLOR</varname> environment variables described above.
+ <varname>systemd.log_color</varname> can be specified without an argument,
+ with the same effect as a positive boolean.</para></listitem>
</varlistentry>
<varlistentry>
for every boot.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>systemd.unified_cgroup_hierarchy</varname></term>
+
+ <listitem><para>When specified without an argument or with a true argument,
+ enables the usage of
+ <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">unified cgroup hierarchy</ulink>
+ (a.k.a. cgroups-v2). When specified with a false argument, fall back to
+ hybrid or full legacy cgroup hierarchy.</para>
+
+ <para>If this option is not specified, the default behaviour is determined
+ during compilation (the <option>--with-default-hierarchy=</option>
+ option). If the kernel does not support unified cgroup hierarchy, the legacy
+ hierarchy will be used even if this option is specified.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.legacy_systemd_cgroup_controller</varname></term>
+
+ <listitem><para>Takes effect if the full unified cgroup hierarchy is not used
+ (see previous option). When specified without an argument or with a true
+ argument, disables the use of "hybrid" cgroup hierarchy (i.e. a cgroups-v2
+ tree used for systemd, and
+ <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v1/">legacy
+ cgroup hierarchy</ulink>, a.k.a. cgroups-v1, for other controllers), and
+ forces a full "legacy" mode. When specified with a false argument, enables
+ the use of "hybrid" hierarchy.</para>
+
+ <para>If this option is not specified, the default behaviour is determined
+ during compilation (the <option>--with-default-hierarchy=</option>
+ option). If the kernel does not support unified cgroup hierarchy, the legacy
+ hierarchy will be used even if this option is specified.</para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>quiet</varname></term>
<varlistentry>
<term><varname>emergency</varname></term>
+ <term><varname>rd.emergency</varname></term>
<term><varname>-b</varname></term>
<listitem><para>Boot into emergency mode. This is equivalent
- to <varname>systemd.unit=emergency.target</varname> and
- provided for compatibility reasons and to be easier to
- type.</para></listitem>
+ to <varname>systemd.unit=emergency.target</varname> or
+ <varname>rd.systemd.unit=emergency.target</varname>, respectively, and
+ provided for compatibility reasons and to be easier to type.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>rescue</varname></term>
+ <term><varname>rd.rescue</varname></term>
<term><varname>single</varname></term>
<term><varname>s</varname></term>
<term><varname>S</varname></term>
<term><varname>1</varname></term>
<listitem><para>Boot into rescue mode. This is equivalent to
- <varname>systemd.unit=rescue.target</varname> and provided for
- compatibility reasons and to be easier to
- type.</para></listitem>
+ <varname>systemd.unit=rescue.target</varname> or
+ <varname>rd.systemd.unit=rescue.target</varname>, respectively, and
+ provided for compatibility reasons and to be easier to type.</para></listitem>
</varlistentry>
<varlistentry>
<refsect1>
<title>See Also</title>
<para>
- The <ulink url="http://www.freedesktop.org/wiki/Software/systemd/">systemd Homepage</ulink>,
+ The <ulink url="https://www.freedesktop.org/wiki/Software/systemd/">systemd Homepage</ulink>,
<citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
projects / thirdparty / systemd.git / blobdiff