Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU General Public License
+ You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
-<refentry id="systemd">
+<refentry id="systemd"
+ xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>systemd</title>
<refnamediv>
<refname>systemd</refname>
<refname>init</refname>
- <refpurpose>systemd System and Session Manager</refpurpose>
+ <refpurpose>systemd system and service manager</refpurpose>
</refnamediv>
<refsynopsisdiv>
<refsect1>
<title>Description</title>
- <para>systemd is a system and session manager for
+ <para>systemd is a system and service manager for
Linux operating systems. When run as first process on
boot (as PID 1), it acts as init system that brings
up and maintains userspace services.</para>
are mostly equivalent when invoked from normal login sessions. See
<citerefentry><refentrytitle>telinit</refentrytitle><manvolnum>8</manvolnum></citerefentry>
for more information.</para>
+
+ <para>When run as system instance, systemd interprets
+ the configuration file
+ <filename>system.conf</filename>, otherwise
+ <filename>user.conf</filename>. See
+ <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for more information.</para>
</refsect1>
<refsect1>
<variablelist>
<varlistentry>
- <term><option>-h</option></term>
- <term><option>--help</option></term>
+ <term><option>--test</option></term>
+
+ <listitem><para>Determine startup
+ sequence, dump it and exit. This is an
+ option useful for debugging
+ only.</para></listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><option>--dump-configuration-items</option></term>
- <listitem><para>Prints a short help
- text and exits.</para></listitem>
+ <listitem><para>Dump understood unit
+ configuration items. This outputs a
+ terse but complete list of
+ configuration items understood in unit
+ definition files.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--unit=</option></term>
<listitem><para>Set default unit to
- activate on startup. If not specified
+ activate on startup. If not specified,
defaults to
<filename>default.target</filename>.</para></listitem>
</varlistentry>
<varlistentry>
- <term><option>--running-as=</option></term>
-
- <listitem><para>Tell systemd to run in
- a particular mode. Argument is one of
- <option>system</option>,
- <option>session</option>. Normally it
- should not be necessary to pass this
- option, as systemd automatically
- detects the mode it is started
- in. This call is hence of little use
- except for
- debugging.</para></listitem>
+ <term><option>--system</option></term>
+ <term><option>--user</option></term>
+
+ <listitem><para>For <option>--system</option>,
+ tell systemd to run a
+ system instance, even if the process ID is
+ not 1, i.e. systemd is not run as init process.
+ <option>--user</option> does the opposite,
+ running a user instance even if the process
+ ID is 1.
+ Normally it should not be necessary to
+ pass these options, as systemd
+ automatically detects the mode it is
+ started in. These options are hence of
+ little use except for debugging. Note
+ that it is not supported booting and
+ maintaining a full system with systemd
+ running in <option>--system</option>
+ mode, but PID not 1. In practice,
+ passing <option>--system</option> explicitly is
+ only useful in conjunction with
+ <option>--test</option>.</para></listitem>
</varlistentry>
<varlistentry>
- <term><option>--test</option></term>
+ <term><option>--dump-core</option></term>
- <listitem><para>Determine startup
- sequence, dump it and exit. This is an
- option useful for debugging
- only.</para></listitem>
+ <listitem><para>Dump core on
+ crash. This switch has no effect when
+ run as user
+ instance.</para></listitem>
</varlistentry>
<varlistentry>
- <term><option>--dump-configuration-items</option></term>
+ <term><option>--crash-shell</option></term>
- <listitem><para>Dump understood unit
- configuration items. This outputs a
- terse but complete list of
- configuration items understood in unit
- definition files.</para></listitem>
+ <listitem><para>Run shell on
+ crash. This switch has no effect when
+ run as user
+ instance.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--confirm-spawn</option></term>
- <listitem><para>Ask for confirmation when spawning processes.</para></listitem>
+ <listitem><para>Ask for confirmation
+ when spawning processes. This switch
+ has no effect when run as user
+ instance.</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>
</varlistentry>
<varlistentry>
- <term><option>--introspect=</option></term>
+ <term><option>--log-target=</option></term>
- <listitem><para>Extract D-Bus
- interface introspection data. This is
- mostly useful at build at install time
- to generate data suitable for the
- D-Bus interfaces
- repository. Optionally the interface
- name for the introspection data may be
- specified. If omitted, the
- introspection data for all interfaces
- is dumped.</para></listitem>
+ <listitem><para>Set log
+ target. Argument must be one of
+ <option>console</option>,
+ <option>journal</option>,
+ <option>kmsg</option>,
+ <option>journal-or-kmsg</option>,
+ <option>null</option>.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--log-level=</option></term>
<listitem><para>Set log level. As
argument this accepts a numerical log
- level or the well-known <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ level or the well-known <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
symbolic names (lowercase):
<option>emerg</option>,
<option>alert</option>,
<option>info</option>,
<option>debug</option>.</para></listitem>
</varlistentry>
- <varlistentry>
- <term><option>--log-target=</option></term>
-
- <listitem><para>Set log
- target. Argument must be one of
- <option>console</option>,
- <option>syslog</option>,
- <option>kmsg</option>,
- <option>syslog-or-kmsg</option>,
- <option>null</option>.</para></listitem>
- </varlistentry>
<varlistentry>
<term><option>--log-color=</option></term>
<listitem><para>Highlight important
log messages. Argument is a boolean
- value. If the argument is omitted it
+ value. If the argument is omitted, it
defaults to
<option>true</option>.</para></listitem>
</varlistentry>
it defaults to
<option>true</option>.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><option>--default-standard-output=</option></term>
+ <term><option>--default-standard-error=</option></term>
+
+ <listitem><para>Sets the default
+ output or error output for all
+ services and sockets, respectively. That is, controls
+ the default for
+ <option>StandardOutput=</option>
+ and <option>StandardError=</option>
+ (see
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details). Takes one of
+ <option>inherit</option>,
+ <option>null</option>,
+ <option>tty</option>,
+ <option>journal</option>,
+ <option>journal+console</option>,
+ <option>syslog</option>,
+ <option>syslog+console</option>,
+ <option>kmsg</option>,
+ <option>kmsg+console</option>. If the
+ argument is omitted
+ <option>--default-standard-output=</option>
+ defaults to <option>journal</option>
+ and
+ <option>--default-standard-error=</option>
+ to
+ <option>inherit</option>.</para></listitem>
+ </varlistentry>
+
+ <xi:include href="standard-options.xml" xpointer="help" />
+ <xi:include href="standard-options.xml" xpointer="version" />
</variablelist>
</refsect1>
<title>Concepts</title>
<para>systemd provides a dependency system between
- various entities called "units". Units encapsulate
- various objects that are relevant for system boot-up
- and maintainance. The majority of units are configured
- in unit configuration files, whose syntax and basic
- set of options is described in
+ various entities called "units" of 12 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
+ described in
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
however some are created automatically from other
- configuration or dynamically from system state. Units
- may be active (meaning started, bound, plugged in, ...
- depending on the unit type), or inactive (meaning
- stopped, unbound, unplugged, ...), as well is in the
+ configuration, dynamically from system state or
+ programmatically at runtime. 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 being activated or deactivated,
- i.e. between the two states. The following unit types
- are available:</para>
+ 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
+ "inactive" and is entered when the service failed in
+ some way (process returned error code on exit, or
+ crashed, or an operation timed out). If this state is
+ entered, the cause will be logged, for later
+ reference. Note that the various unit types may have a
+ number of additional substates, which are mapped to
+ the five generalized unit states described
+ here.</para>
+
+ <para>The following unit types are available:</para>
<orderedlist>
- <listitem><para>Service units, which control
+ <listitem><para>Service units, which start and control
daemons and the processes they consist of. For
details see
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
systemd units, which later may be restored by
activating the saved snapshot unit. For more
information see
- <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
+ <citerefentry><refentrytitle>systemd.snapshot</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
<listitem><para>Timer units are useful for
triggering activation of other units based on
<citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
<listitem><para>Swap units are very similar to
- mount units and encapsulated memory swap
+ mount units and encapsulate memory swap
partitions or files of the operating
- systemd. They are described in <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
+ system. They are described in <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
<listitem><para>Path units may be used
- activate other services when file system
+ to activate other services when file system
objects change or are modified. See
<citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
+ <listitem><para>Slice units may be used to
+ group units which manage system processes
+ (such as service and scope units) in a
+ hierarchical tree for resource management
+ purposes. See
+ <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
+
+ <listitem><para>Scope units are similar to
+ service units, but manage foreign processes
+ instead of starting them as well. See
+ <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
+
</orderedlist>
<para>Units are named as their configuration
files. Some units have special semantics. A detailed
- list you may find in
+ list is available in
<citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
+ <para>systemd knows various kinds of dependencies,
+ including positive and negative requirement
+ dependencies (i.e. <varname>Requires=</varname> and
+ <varname>Conflicts=</varname>) as well as ordering
+ dependencies (<varname>After=</varname> and
+ <varname>Before=</varname>). NB: ordering and
+ requirement dependencies are orthogonal. If only a
+ requirement dependency exists between two units
+ (e.g. <filename>foo.service</filename> requires
+ <filename>bar.service</filename>), but no ordering
+ dependency (e.g. <filename>foo.service</filename>
+ after <filename>bar.service</filename>) and both are
+ requested to start, they will be started in
+ parallel. It is a common pattern that both requirement
+ and ordering dependencies are placed between two
+ units. Also note that the majority of dependencies are
+ implicitly created and maintained by systemd. In most
+ cases, it should be unnecessary to declare additional
+ dependencies manually, however it is possible to do
+ this.</para>
+
+ <para>Application programs and units (via
+ dependencies) may request state changes of units. In
+ systemd, these requests are encapsulated as 'jobs' and
+ maintained in a job queue. Jobs may succeed or can
+ fail, their execution is ordered based on the ordering
+ dependencies of the units they have been scheduled
+ for.</para>
+
<para>On boot systemd activates the target unit
- <filename>default.target</filename> whose job it is to
+ <filename>default.target</filename> whose job is to
activate on-boot services and other on-boot units by
pulling them in via dependencies. Usually the unit
name is just an alias (symlink) for either
<filename>multi-user.target</filename> (for limited
console-only boots for use in embedded or server
environments, or similar; a subset of
- graphical.target). However it is at the discretion of
+ graphical.target). However, it is at the discretion of
the administrator to configure it as an alias to any
other target unit. See
<citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>
for details about these target units.</para>
+ <para>Processes systemd spawns are placed in
+ individual Linux control groups named after the unit
+ which they belong to in the private systemd
+ hierarchy. (see <ulink
+ url="https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>
+ for more information about control groups, or short
+ "cgroups"). systemd uses this to effectively keep
+ track of processes. Control group information is
+ maintained in the kernel, and is accessible via the
+ file system hierarchy (beneath
+ <filename>/sys/fs/cgroup/systemd/</filename>), or in tools
+ such as
+ <citerefentry project='man-pages'><refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ (<command>ps xawf -eo pid,user,cgroup,args</command>
+ is particularly useful to list all processes and the
+ systemd units they belong to.).</para>
+
+ <para>systemd is compatible with the SysV init system
+ to a large degree: SysV init scripts are supported and
+ simply read as an alternative (though limited)
+ configuration file format. The SysV
+ <filename>/dev/initctl</filename> interface is
+ provided, and compatibility implementations of the
+ various SysV client tools are available. In addition to
+ that, various established Unix functionality such as
+ <filename>/etc/fstab</filename> or the
+ <filename>utmp</filename> database are
+ supported.</para>
+
+ <para>systemd has a minimal transaction system: if a
+ unit is requested to start up or shut down it will add
+ it and all its dependencies to a temporary
+ transaction. Then, it will verify if the transaction
+ is consistent (i.e. whether the ordering of all units
+ is cycle-free). If it is not, systemd will try to fix
+ it up, and removes non-essential jobs from the
+ transaction that might remove the loop. Also, systemd
+ tries to suppress non-essential jobs in the
+ transaction that would stop a running service. Finally
+ it is checked whether the jobs of the transaction
+ contradict jobs that have already been queued, and
+ optionally the transaction is aborted then. If all
+ worked out and the transaction is consistent and
+ minimized in its impact it is merged with all already
+ outstanding jobs and added to the run
+ queue. Effectively this means that before executing a
+ requested operation, systemd will verify that it makes
+ sense, fixing it if possible, and only failing if it
+ really cannot work.</para>
+
+ <para>Systemd contains native implementations of
+ various tasks that need to be executed as part of the
+ boot process. For example, it sets the hostname or
+ configures the loopback network device. It also sets
+ up and mounts various API file systems, such as
+ <filename>/sys</filename> or
+ <filename>/proc</filename>.</para>
+
<para>For more information about the concepts and
- ideas behind systemd please refer to the <ulink
+ ideas behind systemd
, please refer to the <ulink
url="http://0pointer.de/blog/projects/systemd.html">Original
- Announcement Document</ulink>.</para>
+ Design Document</ulink>.</para>
+
+ <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
+ Stability Promise</ulink>.</para>
+
+ <para>Units may be generated dynamically at boot and
+ system manager reload time, for example based on other
+ configuration files or parameters passed on the kernel
+ command line. For details see the <ulink
+ url="http://www.freedesktop.org/wiki/Software/systemd/Generators">Generators
+ Specification</ulink>.</para>
+
+ <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> specifications, respectively.</para>
</refsect1>
<refsect1>
<command>pkg-config systemd
--variable=systemdsystemunitdir</command>. Other
directories checked are
- <filename>/usr/local/share/systemd/system</filename>
+ <filename>/usr/local/lib/systemd/system</filename>
and
- <filename>/usr/share/systemd/system</filename>. User
+ <filename>/usr/lib/systemd/system</filename>. User
configuration always takes
precedence. <command>pkg-config
systemd
--variable=systemdsystemconfdir</command>
returns the path of the system
configuration directory. Packages
- should alter the content of these directories
- only with the
- <citerefentry><refentrytitle>systemd-install</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- tool.</para></listitem>
+ should alter the content of these
+ directories only with the
+ <command>enable</command> and
+ <command>disable</command> commands of
+ the
+ <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ tool. Full list of directories is provided in
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+ </para></listitem>
</varlistentry>
</variablelist>
<variablelist>
<varlistentry>
- <term>Session unit directories</term>
+ <term>User unit directories</term>
<listitem><para>Similar rules apply
- for the session unit
+ for the user unit
directories. However, here the <ulink
url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG
Base Directory specification</ulink>
units. Applications should place their
unit files in the directory returned
by <command>pkg-config systemd
- --variable=systemdsessionunitdir</command>. Global
- configuration is done in the
- directory reported by
- <command>pkg-config systemd
- --variable=systemdsessionconfdir</command>. The
- <citerefentry><refentrytitle>systemd-install</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ --variable=systemduserunitdir</command>. Global
+ configuration is done in the directory
+ reported by <command>pkg-config
+ systemd
+ --variable=systemduserconfdir</command>. The
+ <command>enable</command> and
+ <command>disable</command> commands of
+ the
+ <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
tool can handle both global (i.e. for
all users) and private (for one user)
enabling/disabling of
- units.</para></listitem>
+ units. Full list of directories is provided in
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+ </para></listitem>
</varlistentry>
</variablelist>
when figuring out whether a service
shall be enabled. Note that a service
unit with a native unit configuration
- file can be started by activating it
+ file cannot be started by activating it
in the SysV runlevel link
farm.</para></listitem>
</varlistentry>
<variablelist>
<varlistentry>
- <term>SIGTERM</term>
+ <term><constant>SIGTERM</constant></term>
<listitem><para>Upon receiving this
signal the systemd system manager
to <command>systemctl
daemon-reexec</command>.</para>
- <para>systemd session managers will
+ <para>systemd user managers will
start the
<filename>exit.target</filename> unit
when this signal is received. This is
mostly equivalent to
- <command>systemctl --session start
+ <command>systemctl --user start
exit.target</command>.</para></listitem>
</varlistentry>
<varlistentry>
- <term>SIGINT</term>
+ <term><constant>SIGINT</constant></term>
<listitem><para>Upon receiving this
signal the systemd system manager will
<command>systemctl start
ctl-alt-del.target</command>.</para>
- <para>systemd session managers
+ <para>systemd user managers
treat this signal the same way as
- SIGTERM.</para></listitem>
+ <constant>SIGTERM</constant>.</para></listitem>
</varlistentry>
<varlistentry>
- <term>SIGWINCH</term>
+ <term><constant>SIGWINCH</constant></term>
<listitem><para>When this signal is
received the systemd system manager
kbrequest.target</command>.</para>
<para>This signal is ignored by
- systemd session
+ systemd user
managers.</para></listitem>
</varlistentry>
<varlistentry>
- <term>SIGPWR</term>
+ <term><constant>SIGPWR</constant></term>
<listitem><para>When this signal is
received the systemd manager
</varlistentry>
<varlistentry>
- <term>SIGUSR1</term>
+ <term><constant>SIGUSR1</constant></term>
<listitem><para>When this signal is
received the systemd manager will try
</varlistentry>
<varlistentry>
- <term>SIGUSR2</term>
+ <term><constant>SIGUSR2</constant></term>
<listitem><para>When this signal is
received the systemd manager will log
</varlistentry>
<varlistentry>
- <term>SIGHUP</term>
+ <term><constant>SIGHUP</constant></term>
<listitem><para>Reloads the complete
daemon configuration. This is mostly
</varlistentry>
<varlistentry>
- <term>SIGRTMIN+0</term>
+ <term><constant>SIGRTMIN+0</constant></term>
<listitem><para>Enters default mode, starts the
<filename>default.target</filename>
</varlistentry>
<varlistentry>
- <term>SIGRTMIN+1</term>
+ <term><constant>SIGRTMIN+1</constant></term>
<listitem><para>Enters rescue mode,
starts the
</varlistentry>
<varlistentry>
- <term>SIGRTMIN+2</term>
+ <term><constant>SIGRTMIN+2</constant></term>
<listitem><para>Enters emergency mode,
starts the
</varlistentry>
<varlistentry>
- <term>SIGRTMIN+3</term>
+ <term><constant>SIGRTMIN+3</constant></term>
<listitem><para>Halts the machine,
starts the
</varlistentry>
<varlistentry>
- <term>SIGRTMIN+4</term>
+ <term><constant>SIGRTMIN+4</constant></term>
<listitem><para>Powers off the machine,
starts the
</varlistentry>
<varlistentry>
- <term>SIGRTMIN+5</term>
+ <term><constant>SIGRTMIN+5</constant></term>
<listitem><para>Reboots the machine,
starts the
<command>systemctl start
reboot.target</command>.</para></listitem>
</varlistentry>
+
+ <varlistentry>
+ <term><constant>SIGRTMIN+6</constant></term>
+
+ <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>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>SIGRTMIN+13</constant></term>
+
+ <listitem><para>Immediately halts the machine.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>SIGRTMIN+14</constant></term>
+
+ <listitem><para>Immediately powers off the machine.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>SIGRTMIN+15</constant></term>
+
+ <listitem><para>Immediately reboots the machine.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>SIGRTMIN+16</constant></term>
+
+ <listitem><para>Immediately reboots the machine with kexec.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>SIGRTMIN+20</constant></term>
+
+ <listitem><para>Enables display of
+ status messages on the console, as
+ controlled via
+ <varname>systemd.show_status=1</varname>
+ on the kernel command
+ line.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>SIGRTMIN+21</constant></term>
+
+ <listitem><para>Disables display of
+ status messages on the console, as
+ controlled via
+ <varname>systemd.show_status=0</varname>
+ on the kernel command
+ line.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>SIGRTMIN+22</constant></term>
+ <term><constant>SIGRTMIN+23</constant></term>
+
+ <listitem><para>Sets the log level to
+ <literal>debug</literal>
+ (or <literal>info</literal> on
+ <constant>SIGRTMIN+23</constant>), as
+ controlled via
+ <varname>systemd.log_level=debug</varname>
+ (or <varname>systemd.log_level=info</varname>
+ on <constant>SIGRTMIN+23</constant>) on
+ the kernel command
+ line.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>SIGRTMIN+24</constant></term>
+
+ <listitem><para>Immediately exits the
+ manager (only available for --user
+ instances).</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>SIGRTMIN+26</constant></term>
+ <term><constant>SIGRTMIN+27</constant></term>
+ <term><constant>SIGRTMIN+28</constant></term>
+
+ <listitem><para>Sets the log level to
+ <literal>journal-or-kmsg</literal> (or
+ <literal>console</literal> on
+ <constant>SIGRTMIN+27</constant>,
+ <literal>kmsg</literal> on
+ <constant>SIGRTMIN+28</constant>), as
+ controlled via
+ <varname>systemd.log_target=journal-or-kmsg</varname>
+ (or
+ <varname>systemd.log_target=console</varname>
+ on <constant>SIGRTMIN+27</constant> or
+ <varname>systemd.log_target=kmsg</varname>
+ on <constant>SIGRTMIN+28</constant>)
+ on the kernel command
+ line.</para></listitem>
+ </varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Environment</title>
- <variablelist>
+ <variablelist class='environment-variables'>
<varlistentry>
<term><varname>$SYSTEMD_LOG_LEVEL</varname></term>
<listitem><para>systemd reads the
<term><varname>$XDG_DATA_HOME</varname></term>
<term><varname>$XDG_DATA_DIRS</varname></term>
- <listitem><para>The systemd session
+ <listitem><para>The systemd user
manager uses these variables in
accordance to the <ulink
url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG
</variablelist>
</refsect1>
+ <refsect1>
+ <title>Kernel Command Line</title>
+
+ <para>When run as system instance systemd parses a
+ number of kernel command line
+ arguments<footnote><para>If run inside a Linux
+ container these arguments may be passed as command
+ line arguments to systemd itself, next to any of the
+ command line options listed in the Options section
+ above. If run outside of Linux containers, these
+ arguments are parsed from
+ <filename>/proc/cmdline</filename>
+ instead.</para></footnote>:</para>
+
+ <variablelist class='kernel-commandline-options'>
+ <varlistentry>
+ <term><varname>systemd.unit=</varname></term>
+ <term><varname>rd.systemd.unit=</varname></term>
+
+ <listitem><para>Overrides the unit to
+ activate on boot. Defaults to
+ <filename>default.target</filename>. This
+ may be used to temporarily boot into a
+ different boot unit, for example
+ <filename>rescue.target</filename> or
+ <filename>emergency.service</filename>. See
+ <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ for details about these units. The
+ option prefixed with
+ <literal>rd.</literal> is honored
+ only in the initial RAM disk (initrd),
+ while the one that is not prefixed only
+ in the main system.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.dump_core=</varname></term>
+
+ <listitem><para>Takes a boolean
+ argument. If <option>true</option>,
+ systemd dumps core when it
+ crashes. Otherwise, no core dump is
+ created. Defaults to
+ <option>true</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.crash_shell=</varname></term>
+
+ <listitem><para>Takes a boolean
+ argument. If <option>true</option>,
+ systemd spawns a shell when it
+ crashes. Otherwise, no shell is
+ spawned. Defaults to
+ <option>false</option>, for security
+ reasons, as the shell is not protected
+ by any password
+ authentication.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.crash_chvt=</varname></term>
+
+ <listitem><para>Takes an integer
+ argument. If positive systemd
+ activates the specified virtual
+ terminal when it crashes. Defaults to
+ <constant>-1</constant>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.confirm_spawn=</varname></term>
+
+ <listitem><para>Takes a boolean
+ argument. If <option>true</option>,
+ asks for confirmation when spawning
+ processes. Defaults to
+ <option>false</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.show_status=</varname></term>
+
+ <listitem><para>Takes a boolean
+ argument or the constant
+ <constant>auto</constant>. If
+ <option>true</option>, 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>true</option>, unless
+ <option>quiet</option> is passed as
+ kernel command line option in which
+ case it defaults to
+ <constant>auto</constant>.</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>
+
+ <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>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.default_standard_output=</varname></term>
+ <term><varname>systemd.default_standard_error=</varname></term>
+ <listitem><para>Controls default
+ standard output and error output for
+ services, with the same effect as the
+ <option>--default-standard-output=</option>
+ and <option>--default-standard-error=</option>
+ command line arguments described
+ above, respectively.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.setenv=</varname></term>
+
+ <listitem><para>Takes a string
+ argument in the form VARIABLE=VALUE.
+ May be used to set default environment
+ variables to add to forked child processes.
+ May be used more than once to set multiple
+ variables.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>quiet</varname></term>
+
+ <listitem><para>Turn off
+ status output at boot, much like
+ <varname>systemd.show_status=false</varname>
+ would. Note that this option is also
+ read by the kernel itself and disables
+ kernel log output. Passing this option
+ hence turns off the usual output from
+ both the system manager and the kernel.
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>debug</varname></term>
+
+ <listitem><para>Turn on debugging
+ output. This is equivalent to
+ <varname>systemd.log_level=debug</varname>.
+ Note that this option is also read by
+ the kernel itself and enables kernel
+ debug output. Passing this option
+ hence turns on the debug output from
+ both the system manager and the
+ kernel.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>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>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>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>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>2</varname></term>
+ <term><varname>3</varname></term>
+ <term><varname>4</varname></term>
+ <term><varname>5</varname></term>
+
+ <listitem><para>Boot into the
+ specified legacy SysV runlevel. These
+ are equivalent to
+ <varname>systemd.unit=runlevel2.target</varname>,
+ <varname>systemd.unit=runlevel3.target</varname>,
+ <varname>systemd.unit=runlevel4.target</varname>,
+ and <varname>systemd.unit=runlevel5.target</varname>, respectively,
+ and provided for compatibility reasons
+ and to be easier to
+ type.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>locale.LANG=</varname></term>
+ <term><varname>locale.LANGUAGE=</varname></term>
+ <term><varname>locale.LC_CTYPE=</varname></term>
+ <term><varname>locale.LC_NUMERIC=</varname></term>
+ <term><varname>locale.LC_TIME=</varname></term>
+ <term><varname>locale.LC_COLLATE=</varname></term>
+ <term><varname>locale.LC_MONETARY=</varname></term>
+ <term><varname>locale.LC_MESSAGES=</varname></term>
+ <term><varname>locale.LC_PAPER=</varname></term>
+ <term><varname>locale.LC_NAME=</varname></term>
+ <term><varname>locale.LC_ADDRESS=</varname></term>
+ <term><varname>locale.LC_TELEPHONE=</varname></term>
+ <term><varname>locale.LC_MEASUREMENT=</varname></term>
+ <term><varname>locale.LC_IDENTIFICATION=</varname></term>
+
+ <listitem><para>Set the system locale
+ to use. This overrides the settings in
+ <filename>/etc/locale.conf</filename>. For
+ more information see
+ <citerefentry><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ and
+ <citerefentry><refentrytitle>locale</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
+ </para></listitem>
+ </varlistentry>
+ </variablelist>
+
+ <para>For other kernel command line parameters
+ understood by components of the core OS, please refer
+ to
+ <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
+ </refsect1>
+
<refsect1>
<title>Sockets and FIFOs</title>
<variablelist>
<varlistentry>
- <term><filename>@/org/freedesktop/systemd1/notify</filename></term>
+ <term><filename>/run/systemd/notify</filename></term>
<listitem><para>Daemon status
- notification socket. This is an AF_UNIX
- datagram socket in the Linux abstract
- namespace, and is used to implement
- the daemon notification logic as
- implemented by
+ notification socket. This is an
+ <constant>AF_UNIX</constant> datagram socket and is used to
+ implement the daemon notification
+ logic as implemented by
<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
</varlistentry>
<varlistentry>
- <term><filename>@/org/freedesktop/systemd1/logger</filename></term>
+ <term><filename>/run/systemd/shutdownd</filename></term>
<listitem><para>Used internally by the
- <filename>systemd-logger.service</filename>
- unit to connect STDOUT and/or STDERR
- of spawned processes to
- <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- or the kernel log buffer. This is an
- AF_UNIX stream socket in the Linux
- abstract namespace.</para></listitem>
+ <citerefentry><refentrytitle>shutdown</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ tool to implement delayed
+ shutdowns. This is an <constant>AF_UNIX</constant> datagram
+ socket.</para></listitem>
</varlistentry>
<varlistentry>
- <term><filename>@/org/freedesktop/systemd1/private</filename></term>
+ <term><filename>/run/systemd/private</filename></term>
<listitem><para>Used internally as
communication channel between
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
and the systemd process. This is an
- AF_UNIX stream socket in the Linux
- abstract namespace. This interface is
- private to systemd and should not be
- used in external
+ <constant>AF_UNIX</constant> stream socket. This interface
+ is private to systemd and should not
+ be used in external
projects.</para></listitem>
</varlistentry>
<refsect1>
<title>See Also</title>
<para>
+ The <ulink url="http://www.freedesktop.org/wiki/Software/systemd/">systemd Homepage</ulink>,
+ <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd-install</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-notify</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
</para>
</refsect1>
~ianmdlvl / elogind.git / blobdiff