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/>.
-->
<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>
<para>When run as system instance, systemd interprets
the configuration file
<filename>system.conf</filename>, otherwise
- <filename>session.conf</filename>. See
+ <filename>user.conf</filename>. See
<citerefentry><refentrytitle>systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for more information.</para>
</refsect1>
</varlistentry>
<varlistentry>
<term><option>--system</option></term>
- <term><option>--session</option></term>
+ <term><option>--user</option></term>
<listitem><para>Tell systemd to run a
- system instance (resp. session
+ system instance (resp. user
instance), even if the process ID is
- not 1 (resp. is 1), i.e. systemd is not
- (resp. is) run as init process.
+ not 1 (resp. is 1), i.e. systemd is
+ not (resp. is) run as init process.
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.</para></listitem>
+ 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>--dump-core</option></term>
- <listitem><para>Dump core on crash. This switch has no effect when run as session instance.</para></listitem>
+ <listitem><para>Dump core on
+ crash. This switch has no effect when
+ run as user
+ instance.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--crash-shell</option></term>
- <listitem><para>Run shell on crash. This switch has no effect when run as session instance.</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. This switch has no effect when run as session instance.</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
- session instance. Takes a boolean
- argument which may be omitted
- which is interpreted as
+ 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>
<listitem><para>Controls whether
output of SysV init scripts will be
directed to the console. This switch
- has no effect when run as session
+ has no effect when run as user
instance. Takes a boolean argument
which may be omitted which is
interpreted as
<listitem><para>Set log
target. Argument must be one of
<option>console</option>,
+ <option>journal</option>,
<option>syslog</option>,
<option>kmsg</option>,
+ <option>journal-or-kmsg</option>,
<option>syslog-or-kmsg</option>,
<option>null</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 resp. error output for all
+ services and sockets, i.e. controls
+ the default for
+ <option>StandardOutput=</option>
+ resp. <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>
</variablelist>
</refsect1>
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
- 'maintenance' state is available as well which is very
+ '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
<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
to activate other services when file system
<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,
this.</para>
<para>Application programs and units (via
- dependencies) may requests state changes of units. In
+ 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
track of processes. Control group information is
maintained in the kernel, and is accessible via the
file system hierarchy (beneath
- <filename>/cgroup/systemd/</filename>), or in tools
+ <filename>/sys/fs/cgroup/systemd/</filename>), or in tools
such as
<citerefentry><refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum></citerefentry>
(<command>ps xawf -eo pid,user,cgroup,args</command>
ideas behind systemd please refer to the <ulink
url="http://0pointer.de/blog/projects/systemd.html">Original
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>
</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
<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
+ --variable=systemduserunitdir</command>. Global
configuration is done in the directory
reported by <command>pkg-config
systemd
- --variable=systemdsessionconfdir</command>. The
+ --variable=systemduserconfdir</command>. The
<command>enable</command> and
<command>disable</command> commands of
the
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>
<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>
</varlistentry>
kbrequest.target</command>.</para>
<para>This signal is ignored by
- systemd session
+ systemd user
managers.</para></listitem>
</varlistentry>
<command>systemctl start
reboot.target</command>.</para></listitem>
</varlistentry>
+
+ <varlistentry>
+ <term>SIGRTMIN+6</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>SIGRTMIN+13</term>
+
+ <listitem><para>Immediately halts the machine.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>SIGRTMIN+14</term>
+
+ <listitem><para>Immediately powers off the machine.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>SIGRTMIN+15</term>
+
+ <listitem><para>Immediately reboots the machine.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>SIGRTMIN+16</term>
+
+ <listitem><para>Immediately reboots the machine with kexec.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>SIGRTMIN+20</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>SIGRTMIN+21</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>SIGRTMIN+22</term>
+ <term>SIGRTMIN+23</term>
+
+ <listitem><para>Sets the log level to
+ <literal>debug</literal>
+ (resp. <literal>info</literal> on
+ <literal>SIGRTMIN+23</literal>), as
+ controlled via
+ <varname>systemd.log_level=debug</varname>
+ (resp. <varname>systemd.log_level=info</varname>
+ on <literal>SIGRTMIN+23</literal>) on
+ the kernel command
+ line.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>SIGRTMIN+26</term>
+ <term>SIGRTMIN+27</term>
+ <term>SIGRTMIN+28</term>
+ <term>SIGRTMIN+29</term>
+
+ <listitem><para>Sets the log level to
+ <literal>journal-or-kmsg</literal>
+ (resp. <literal>console</literal> on
+ <literal>SIGRTMIN+27</literal>;
+ resp. <literal>kmsg</literal> on
+ <literal>SIGRTMIN+28</literal>;
+ resp. <literal>syslog-or-kmsg</literal>
+ on <literal>SIGRTMIN+29</literal>), as
+ controlled via
+ <varname>systemd.log_target=journal-or-kmsg</varname>
+ (resp. <varname>systemd.log_target=console</varname>
+ on <literal>SIGRTMIN+27</literal>;
+ resp. <varname>systemd.log_target=kmsg</varname>
+ on <literal>SIGRTMIN+28</literal>;
+ resp
+ <varname>systemd.log_target=syslog-or-kmsg</varname>
+ on <literal>SIGRTMIN+29</literal>) on
+ the kernel command
+ line.</para></listitem>
+ </varlistentry>
</variablelist>
</refsect1>
<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
<refsect1>
<title>Kernel Command Line</title>
- <para>When run as system instance systemd parses a few kernel command line arguments:</para>
+ <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>
<varlistentry>
<listitem><para>Takes a boolean
argument. If <option>true</option>
systemd spawns a shell when it
- crashes. Otherwise no core dump is
- created. Defaults to
+ crashes. Otherwise no shell is
+ spawned. Defaults to
<option>false</option>, for security
reasons, as the shell is not protected
by any password
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/error output for
+ services, with the same effect as the
+ <option>--default-standard-output=</option>
+ resp. <option>--default-standard-error=</option>
+ command line arguments described
+ above.</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
+ environment variables for the init
+ process and all its children at boot
+ time. May be used more than once to
+ set multiple variables. If the equal
+ sign and variable are missing unsets
+ an environment variable which might be
+ passed in from the initial ram
+ disk.</para></listitem>
+ </varlistentry>
+
</variablelist>
</refsect1>
<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
+ AF_UNIX 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>
-
- <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>
- </varlistentry>
-
- <varlistentry>
- <term><filename>@/org/freedesktop/systemd1/shutdown</filename></term>
+ <term><filename>/run/systemd/shutdownd</filename></term>
<listitem><para>Used internally by the
<citerefentry><refentrytitle>shutdown</refentrytitle><manvolnum>8</manvolnum></citerefentry>
tool to implement delayed
shutdowns. This is an AF_UNIX datagram
- socket in the Linux abstract
- namespace.</para></listitem>
+ 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
+ AF_UNIX stream socket. This interface
+ is private to systemd and should not
+ be used in external
projects.</para></listitem>
</varlistentry>