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.special</refname>
- <refpurpose>special systemd units</refpurpose>
+ <refpurpose>Special systemd units</refpurpose>
</refnamediv>
<refsynopsisdiv>
- <para><filename>basic.target</filename></para>
- <para><filename>ctrl-alt-del.target</filename></para>
- <para><filename>default.target</filename></para>
- <para><filename>emergency.service</filename></para>
- <para><filename>graphical.target</filename></para>
- <para><filename>halt.target</filename></para>
- <para><filename>kbrequest.target</filename></para>
- <para><filename>local-fs.target</filename></para>
- <para><filename>multi-user.target</filename></para>
- <para><filename>network.target</filename></para>
- <para><filename>nss-lookup.target</filename></para>
- <para><filename>poweroff.target</filename></para>
- <para><filename>reboot.target</filename></para>
- <para><filename>remote-fs.target</filename></para>
- <para><filename>rescue.target</filename></para>
- <para><filename>rpcbind.target</filename></para>
- <para><filename>rtc-set.target</filename></para>
- <para><filename>runlevel0.target</filename>,
- <filename>runlevel0.target</filename>,
- <filename>runlevel1.target</filename>,
- <filename>runlevel2.target</filename>,
- <filename>runlevel3.target</filename>,
- <filename>runlevel4.target</filename>,
- <filename>runlevel5.target</filename>,
- <filename>runlevel6.target</filename></para>
- <para><filename>shutdown.target</filename></para>
- <para><filename>sigpwr.target</filename></para>
- <para><filename>sockets.target</filename></para>
- <para><filename>swap.target</filename></para>
- <para><filename>syslog.target</filename></para>
- <para><filename>systemd-initctl.service</filename>, <filename>systemd-initctl.socket</filename></para>
- <para><filename>systemd-logger.service</filename>, <filename>systemd-logger.socket</filename></para>
+ <para><filename>basic.target</filename>,
+ <filename>bluetooth.target</filename>,
+ <filename>ctrl-alt-del.target</filename>,
+ <filename>cryptsetup.target</filename>,
+ <filename>dbus.service</filename>,
+ <filename>dbus.socket</filename>,
+ <filename>default.target</filename>,
+ <filename>display-manager.service</filename>,
+ <filename>emergency.target</filename>,
+ <filename>exit.target</filename>,
+ <filename>final.target</filename>,
+ <filename>getty.target</filename>,
+ <filename>graphical.target</filename>,
+ <filename>halt.target</filename>,
+ <filename>hibernate.target</filename>,
+ <filename>hybrid-sleep.target</filename>,
+ <filename>initrd-fs.target</filename>,
+ <filename>kbrequest.target</filename>,
+ <filename>kexec.target</filename>,
+ <filename>local-fs.target</filename>,
+ <filename>local-fs-pre.target</filename>,
+ <filename>multi-user.target</filename>,
+ <filename>network.target</filename>,
+ <filename>network-online.target</filename>,
+ <filename>nss-lookup.target</filename>,
+ <filename>nss-user-lookup.target</filename>,
+ <filename>paths.target</filename>,
+ <filename>poweroff.target</filename>,
+ <filename>printer.target</filename>,
+ <filename>reboot.target</filename>,
+ <filename>remote-fs.target</filename>,
+ <filename>remote-fs-pre.target</filename>,
+ <filename>rescue.target</filename>,
+ <filename>initrd-root-fs.target</filename>,
+ <filename>rpcbind.target</filename>,
+ <filename>runlevel2.target</filename>,
+ <filename>runlevel3.target</filename>,
+ <filename>runlevel4.target</filename>,
+ <filename>runlevel5.target</filename>,
+ <filename>shutdown.target</filename>,
+ <filename>sigpwr.target</filename>,
+ <filename>sleep.target</filename>,
+ <filename>smartcard.target</filename>,
+ <filename>sockets.target</filename>,
+ <filename>sound.target</filename>,
+ <filename>suspend.target</filename>,
+ <filename>swap.target</filename>,
+ <filename>sysinit.target</filename>,
+ <filename>syslog.socket</filename>,
+ <filename>system-update.target</filename>,
+ <filename>time-sync.target</filename>,
+ <filename>timers.target</filename>,
+ <filename>umount.target</filename>,
+ <filename>-.slice</filename>,
+ <filename>system.slice</filename>,
+ <filename>user.slice</filename>,
+ <filename>machine.slice</filename></para>
</refsynopsisdiv>
<refsect1>
<term><filename>basic.target</filename></term>
<listitem>
<para>A special target unit
- covering early boot-up.</para>
+ covering basic boot-up.</para>
<para>systemd automatically
adds dependencies of the types
- Requires and After for this
- target unit to all SysV
- service units configured for
- runlevel 1 to 5.</para>
- <para>systemd automatically
- adds dependencies of the types
- Wants and After for all
- SysV service units configured
- for runlevels that are not 0
- to 6 to this target unit.
- This covers the special
- boot-up runlevels some
- distributions have, such as S
- or b.</para>
+ <varname>Requires=</varname>
+ and <varname>After=</varname>
+ for this target unit to all
+ services (except for those
+ with
+ <varname>DefaultDependencies=no</varname>).</para>
+
+ <para>Usually this should
+ pull-in all mount points, swap
+ devices, sockets, timers, and
+ path units and other basic
+ initialization necessary for
+ general purpose
+ daemons.</para>
</listitem>
</varlistentry>
<varlistentry>
<filename>reboot.target</filename>.</para>
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><filename>cryptsetup.target</filename></term>
+ <listitem>
+ <para>A target that pulls in
+ setup services for all
+ encrypted block
+ devices.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><filename>dbus.service</filename></term>
+ <listitem>
+ <para>A special unit for the
+ D-Bus bus daemon. As soon as
+ this service is fully started
+ up systemd will connect to it
+ and register its
+ service.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><filename>dbus.socket</filename></term>
+ <listitem>
+ <para>A special unit for the
+ D-Bus system bus socket. All
+ units with
+ <varname>Type=dbus</varname>
+ automatically gain a
+ dependency on this
+ unit.</para>
+ </listitem>
+ </varlistentry>
<varlistentry>
<term><filename>default.target</filename></term>
<listitem>
<filename>multi-user.target</filename>
or
<filename>graphical.target</filename>.</para>
+
<para>The default unit systemd
starts at bootup can be
- overriden with the
- <varname>systemd.default=</varname>
+ overridden with the
+ <varname>systemd.unit=</varname>
kernel command line option.</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>emergency.service</filename></term>
+ <term><filename>display-manager.service</filename></term>
<listitem>
- <para>A special service unit
+ <para>The display manager
+ service. Usually this should
+ be aliased (symlinked) to
+ <filename>gdm.service</filename>
+ or a similar display manager
+ service.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><filename>emergency.target</filename></term>
+ <listitem>
+ <para>A special target unit
that starts an emergency
shell on the main
console. This unit is supposed
to be used with the kernel
command line option
- <varname>systemd.default=</varname>
+ <varname>systemd.unit=</varname>
and has otherwise little use.
</para>
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><filename>final.target</filename></term>
+ <listitem>
+ <para>A special target unit
+ that is used during the
+ shutdown logic and may be used
+ to pull in late services after
+ all normal services are
+ already terminated and all
+ mounts unmounted.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><filename>getty.target</filename></term>
+ <listitem>
+ <para>A special target unit
+ that pulls in statically
+ configured local TTY
+ <filename>getty</filename>
+ instances.
+ </para>
+ </listitem>
+ </varlistentry>
<varlistentry>
<term><filename>graphical.target</filename></term>
<listitem>
<filename>multi-user.target</filename>.</para>
<para>Units that are needed
- for graphical login shall add
- Wants dependencies for their
- unit to this unit (or
+ for graphical logins shall add
+ <varname>Wants=</varname>
+ dependencies for their unit to
+ this unit (or
<filename>multi-user.target</filename>)
- during installation.</para>
+ during installation. This is
+ best configured via
+ <varname>WantedBy=graphical.target</varname>
+ in the unit's
+ <literal>[Install]</literal>
+ section.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><filename>hibernate.target</filename></term>
+ <listitem>
+ <para>A special target unit
+ for hibernating the
+ system. This pulls in
+ <filename>sleep.target</filename>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><filename>hybrid-sleep.target</filename></term>
+ <listitem>
+ <para>A special target unit
+ for hibernating and suspending the
+ system at the same time. This pulls in
+ <filename>sleep.target</filename>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>halt.target</filename></term>
<listitem>
<para>A special target unit
- for shutting down and halting the system.</para>
+ for shutting down and halting
+ the system. Note that this
+ target is distinct from
+ <filename>poweroff.target</filename>
+ in that it generally really
+ just halts the system rather
+ than powering it down.</para>
<para>Applications wanting to
halt the system should start
this unit.</para>
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><filename>initrd-fs.target</filename></term>
+ <listitem>
+ <para><citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ automatically adds
+ dependencies of type
+ <varname>Before=</varname> to
+ <filename>sysroot-usr.mount</filename>
+ and all mount points found in
+ <filename>/etc/fstab</filename>
+ that have the
+ <option>auto</option> and
+ <option>x-initrd.mount</option>
+ mount options set.
+ </para>
+ </listitem>
+ </varlistentry>
<varlistentry>
<term><filename>kbrequest.target</filename></term>
<listitem>
<filename>rescue.target</filename>.</para>
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><filename>kexec.target</filename></term>
+ <listitem>
+ <para>A special target unit
+ for shutting down and rebooting the system via kexec.</para>
+
+ <para>Applications wanting to
+ reboot the system with kexec should start
+ this unit.</para>
+ </listitem>
+ </varlistentry>
<varlistentry>
<term><filename>local-fs.target</filename></term>
<listitem>
- <para>systemd automatically
+ <para><citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ automatically adds
+ dependencies of type
+ <varname>Before=</varname> to
+ all mount units that refer to
+ local mount points for this
+ target unit. In addition, it
adds dependencies of type
- After to all mount units that
- refer to local mount points
- for this target unit. In
- addition, systemd adds
- dependencies of type Wants to
+ <varname>Wants=</varname> to
this target unit for those
mounts listed in
<filename>/etc/fstab</filename>
that have the
- <literal>auto</literal> and
- <literal>comment=systemd.mount</literal>
- mount options set.</para>
-
- <para>systemd automatically
- adds dependencies of type
- After for this target unit to
- all SysV init script service
- units with an LSB header
- referring to the
- <literal>$local_fs</literal>
- facility.</para>
+ <option>auto</option> mount
+ option set.</para>
</listitem>
</varlistentry>
<varlistentry>
<para>Units that are needed
for a multi-user system shall
- add Wants dependencies to
- this unit for their unit during
- installation.</para>
+ add <varname>Wants=</varname>
+ dependencies for their unit to
+ this unit during
+ installation. This is best
+ configured via
+ <varname>WantedBy=multi-user.target</varname>
+ in the unit's
+ <literal>[Install]</literal>
+ section.</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>network.target</filename></term>
+ <term><filename>network-online.target</filename></term>
<listitem>
- <para>systemd automatically
- adds dependencies of type
- After for this target unit to
- all SysV init script service
- units with an LSB header
- referring to the
- <literal>$network</literal>
- facility.</para>
- </listitem>
+ <para>Units that strictly
+ require a configured network
+ connection should pull in
+ <filename>network-online.target</filename>
+ (via a
+ <varname>Wants=</varname> type
+ dependency) and order
+ themselves after it. This
+ target unit is intended to
+ pull in a service that delays
+ further execution until the
+ network is sufficiently set
+ up. What precisely this
+ requires is left to the
+ implementation of the network
+ managing service.</para>
+
+ <para>Note the distinction
+ between this unit and
+ <filename>network.target</filename>. This
+ unit is an active unit
+ (i.e. pulled in by the
+ consumer rather than the
+ provider of this
+ functionality) and pulls in a
+ service which possibly adds
+ substantial delays to further
+ execution. In contrast,
+ <filename>network.target</filename>
+ is a passive unit (i.e. pulled
+ in by the provider of the
+ functionality, rather than the
+ consumer) that usually does
+ not delay execution
+ much. Usually,
+ <filename>network.target</filename>
+ is part of the boot of most
+ systems, while
+ <filename>network-online.target</filename>
+ is not, except when at least
+ one unit requires it. Also see
+ <ulink
+ url="http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget">Running
+ Services After the Network is
+ up</ulink> for more
+ information.</para>
+
+ <para>All mount units for
+ remote network file systems
+ automatically pull in this
+ unit, and order themselves
+ after it. Note that networking
+ daemons that simply provide
+ functionality to other hosts
+ generally do not need to pull
+ this in.</para>
+ </listitem>
</varlistentry>
<varlistentry>
- <term><filename>nss-lookup.target</filename></term>
+ <term><filename>paths.target</filename></term>
<listitem>
- <para>systemd automatically
- adds dependencies of type
- After for this target unit to
- all SysV init script service
- units with an LSB header
- referring to the
- <literal>$named</literal>
- facility.</para>
+ <para>A special target unit
+ that sets up all path units
+ (see
+ <citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details) that shall be
+ active after boot.</para>
+
+ <para>It is recommended that
+ path units installed by
+ applications get pulled in via
+ <varname>Wants=</varname>
+ dependencies from this
+ unit. This is best configured
+ via a
+ <varname>WantedBy=paths.target</varname>
+ in the path unit's
+ <literal>[Install]</literal>
+ section.</para>
</listitem>
</varlistentry>
<varlistentry>
<para>systemd automatically
adds dependencies of type
- After for this target unit to
- all SysV init script service
- units with an LSB header
- referring to the
- <literal>$remote-fs</literal>
+ <varname>After=</varname> for
+ this target unit to all SysV
+ init script service units with
+ an LSB header referring to the
+ <literal>$remote_fs</literal>
facility.</para>
</listitem>
</varlistentry>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>rpcbind.target</filename></term>
+ <term><filename>initrd-root-fs.target</filename></term>
<listitem>
- <para>systemd automatically
- adds dependencies of type
- After for this target unit to
- all SysV init script service
- units with an LSB header
- referring to the
- <literal>$rpcbind</literal>
- facility.</para>
+ <para><citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ automatically adds
+ dependencies of type
+ <varname>Before=</varname> to
+ the
+ <filename>sysroot.mount</filename>
+ unit, which is generated from
+ the kernel command line.
+ </para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>rtc-set.target</filename></term>
+ <term><filename>runlevel2.target</filename></term>
+ <term><filename>runlevel3.target</filename></term>
+ <term><filename>runlevel4.target</filename></term>
+ <term><filename>runlevel5.target</filename></term>
<listitem>
- <para>systemd automatically
- adds dependencies of type
- After for this target unit to
- all SysV init script service
- units with an LSB header
- referring to the
- <literal>$time</literal>
- facility.</para>
+ <para>These are targets that
+ are called whenever the SysV
+ compatibility code asks for
+ runlevel 2, 3, 4, 5,
+ respectively. It is a good
+ idea to make this an alias for
+ (i.e. symlink to)
+ <filename>multi-user.target</filename>
+ (for runlevel 2) or
+ <filename>graphical.target</filename>
+ (the others).</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>runlevel0.target</filename></term>
+ <term><filename>shutdown.target</filename></term>
<listitem>
- <para>This is a target that is
- called whever the SysV
- compatibility code asks for
- runlevel 0. This is an alias
- for
- <filename>poweroff.target</filename>,
- for compatibility with
- SysV.</para>
+ <para>A special target unit
+ that terminates the services
+ on system shutdown.</para>
+
+ <para>Services that shall be
+ terminated on system shutdown
+ shall add <varname>Conflicts=</varname>
+ dependencies to this unit for
+ their service unit, which is
+ implicitly done when
+ <varname>DefaultDependencies=yes</varname>
+ is set (the default).</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>runlevel1.target</filename></term>
+ <term><filename>sigpwr.target</filename></term>
<listitem>
- <para>This is a target that is
- called whever the SysV
- compatibility code asks for
- runlevel 1. This is an alias
- for
- <filename>rescue.target</filename>,
- for compatibility with
- SysV.</para>
+ <para>A special target that is
+ started when systemd receives
+ the SIGPWR process signal,
+ which is normally sent by the
+ kernel or UPS daemons when
+ power fails.</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>runlevel2.target</filename></term>
+ <term><filename>sleep.target</filename></term>
<listitem>
- <para>This is a target that is
- called whever the SysV
- compatibility code asks for
- runlevel 2. It is a good idea
- to make this an alias for
- (i.e. symlink to)
- <filename>multi-user.target</filename>.</para>
+ <para>A special target unit
+ that is pulled in by
+ <filename>suspend.target</filename>,
+ <filename>hibernate.target</filename>
+ and
+ <filename>hybrid-sleep.target</filename>
+ and may be used to hook units
+ into the sleep state
+ logic.</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>runlevel3.target</filename></term>
+ <term><filename>sockets.target</filename></term>
<listitem>
- <para>This is a target that is
- called whever the SysV
- compatibility code asks for
- runlevel 3. It is a good idea
- to make this an alias for
- (i.e. symlink to)
- <filename>multi-user.target</filename>
- or
- <filename>graphical.target</filename>.</para>
+ <para>A special target unit
+ that sets up all socket
+ units.(see
+ <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details) that shall be
+ active after boot.</para>
+
+ <para>Services that can be
+ socket-activated shall add
+ <varname>Wants=</varname>
+ dependencies to this unit for
+ their socket unit during
+ installation. This is best
+ configured via a
+ <varname>WantedBy=sockets.target</varname>
+ in the socket unit's
+ <literal>[Install]</literal>
+ section.</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>runlevel4.target</filename></term>
+ <term><filename>suspend.target</filename></term>
<listitem>
- <para>This is a target that is
- called whever the SysV
- compatibility code asks for
- runlevel 4. It is a good idea
- to make this an alias for
- (i.e. symlink to)
- <filename>multi-user.target</filename>
- or
- <filename>graphical.target</filename>.</para>
+ <para>A special target unit
+ for suspending the
+ system. This pulls in
+ <filename>sleep.target</filename>.</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>runlevel5.target</filename></term>
+ <term><filename>swap.target</filename></term>
<listitem>
- <para>This is a target that is
- called whever the SysV
- compatibility code asks for
- runlevel 5. It is a good idea
- to make this an alias for
- (i.e. symlink to)
- <filename>multi-user.target</filename>
- or
- <filename>graphical.target</filename>.</para>
+ <para>Similar to
+ <filename>local-fs.target</filename>, but for swap
+ partitions and swap
+ files.</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>runlevel6.target</filename></term>
+ <term><filename>sysinit.target</filename></term>
<listitem>
- <para>This is a target that is
- called whever the SysV
- compatibility code asks for
- runlevel 6. This is an alias
- for
- <filename>reboot.target</filename>,
- for compatibility with
- SysV.</para>
+ <para>A special target unit
+ covering early boot-up scripts.</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>shutdown.target</filename></term>
+ <term><filename>syslog.socket</filename></term>
+ <listitem>
+ <para>The socket unit
+ syslog implementations should
+ listen on. All userspace log
+ messages will be made
+ available on this socket. For
+ more information about syslog
+ integration, please consult
+ the <ulink
+ url="http://www.freedesktop.org/wiki/Software/systemd/syslog">Syslog
+ Interface</ulink>
+ document.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><filename>system-update.target</filename></term>
<listitem>
<para>A special target unit
- that terminates the services
- on system shutdown.</para>
+ that is used for off-line
+ system updates.
+ <citerefentry><refentrytitle>systemd-system-update-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ will redirect the boot process
+ to this target if
+ <filename>/system-update</filename>
+ exists. For more information
+ see the <ulink
+ url="http://freedesktop.org/wiki/Software/systemd/SystemUpdates">System
+ Updates
+ Specification</ulink>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><filename>timers.target</filename></term>
+ <listitem>
+ <para>A special target unit
+ that sets up all timer
+ units (see
+ <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details) that shall be
+ active after boot.</para>
- <para>Services that shall be
- terminated on system shutdown
+ <para>It is recommended that
+ timer units installed by
+ applications get pulled in via
+ <varname>Wants=</varname>
+ dependencies from this
+ unit. This is best configured
+ via
+ <varname>WantedBy=timers.target</varname>
+ in the timer unit's
+ <literal>[Install]</literal>
+ section.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><filename>umount.target</filename></term>
+ <listitem>
+ <para>A special target unit
+ that umounts all mount and
+ automount points on system
+ shutdown.</para>
+
+ <para>Mounts that shall be
+ unmounted on system shutdown
shall add Conflicts
dependencies to this unit for
- their service unit during
- installation.</para>
+ their mount unit, which is
+ implicitly done when
+ <varname>DefaultDependencies=yes</varname>
+ is set (the default).</para>
+ </listitem>
+ </varlistentry>
- <para>systemd automatically
- adds dependencies of type
- Conflicts to this target unit
- for all SysV init script
- service units that shall be
- terminated in SysV runlevels 0
- or 6.</para>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Special System Units for Devices</title>
+
+ <para>Some target units are automatically pulled in as
+ devices of certain kinds show up in the system. These
+ may be used to automatically activate various services
+ based on the specific type of the available
+ hardware.</para>
+
+ <variablelist>
+ <varlistentry>
+ <term><filename>bluetooth.target</filename></term>
+ <listitem>
+ <para>This target is started
+ automatically as soon as a
+ Bluetooth controller is
+ plugged in or becomes
+ available at boot.</para>
+
+ <para>This may be used to pull
+ in Bluetooth management
+ daemons dynamically when
+ Bluetooth hardware is
+ found.</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>sigpwr.target</filename></term>
+ <term><filename>printer.target</filename></term>
<listitem>
- <para>A special target that is
- started when systemd receives
- the SIGPWR process signal,
- which is normally sent by the
- kernel or UPS daemons when
- power fails.</para>
+ <para>This target is started
+ automatically as soon as a
+ printer is plugged in or
+ becomes available at
+ boot.</para>
+
+ <para>This may be used to pull
+ in printer management
+ daemons dynamically when
+ printer hardware is
+ found.</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>sockets.target</filename></term>
+ <term><filename>smartcard.target</filename></term>
<listitem>
- <para>A special target unit
- that sets up all service
- sockets.</para>
+ <para>This target is started
+ automatically as soon as a
+ smartcard controller is
+ plugged in or becomes
+ available at boot.</para>
- <para>Services that can be
- socket-activated shall add
- Wants dependencies to this
- unit for their socket unit
- during installation.</para>
+ <para>This may be used to pull
+ in smartcard management
+ daemons dynamically when
+ smartcard hardware is
+ found.</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>swap.target</filename></term>
+ <term><filename>sound.target</filename></term>
<listitem>
- <para>Similar to
- <filename>local-fs.target</filename>, but for swap
- partitions and swap
- files.</para>
+ <para>This target is started
+ automatically as soon as a
+ sound card is plugged in or
+ becomes available at
+ boot.</para>
+
+ <para>This may be used to pull
+ in audio management daemons
+ dynamically when audio
+ hardware is found.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Special Passive System Units </title>
+
+ <para>A number of special system targets are defined
+ that can be used to properly order boot-up of optional
+ services. These targets are generally not part of the
+ initial boot transaction, unless they are explicitly
+ pulled in by one of the implementing services. Note
+ specifically, that these <emphasis>passive</emphasis>
+ target units are generally not pulled in by the
+ consumer of a service, but by the provider of the
+ service. This means: a consuming service should order
+ itself after these targets (as appropriate), but not
+ pull it in. A providing service should order itself
+ before these targets (as appropriate) and pull it in
+ (via a <varname>Wants=</varname> type
+ dependency).</para>
+
+ <para>Note that these passive units cannot be started
+ manually, i.e. <literal>systemctl start
+ time-sync.target</literal> will fail with an
+ error. They can only be pulled in by dependency. This
+ is enforced since they exist for ordering purposes
+ only and thus are not useful as only unit within a
+ transaction.</para>
+
+ <variablelist>
+ <varlistentry>
+ <term><filename>local-fs-pre.target</filename></term>
+ <listitem>
+ <para>This target unit is
+ automatically ordered before
+ all local mount points marked
+ with <option>auto</option>
+ (see above). It can be used to
+ execute certain units before
+ all local mounts.</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>syslog.target</filename></term>
+ <term><filename>network.target</filename></term>
<listitem>
+ <para>This unit is supposed to
+ indicate when network
+ functionality is available,
+ but it is only very weakly
+ defined what that is supposed
+ to mean, with one exception:
+ at shutdown, a unit that is
+ ordered after
+ <filename>network.target</filename>
+ will be stopped before the
+ network -- to whatever level
+ it might be set up then -- is
+ shut down. Also see <ulink
+ url="http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget">Running
+ Services After the Network is
+ up</ulink> for more
+ information. Also see
+ <filename>network-online.target</filename>
+ described above.</para>
+
<para>systemd automatically
adds dependencies of type
- After for this target unit to
- all SysV init script service
- units with an LSB header
- referring to the
- <literal>$syslog</literal>
+ <varname>After=</varname> for
+ this target unit to all SysV
+ init script service units with
+ an LSB header referring to the
+ <literal>$network</literal>
facility.</para>
- <para>Administrators should
- ensure that this target pulls
- in a service unit with the
- name or alias of
- <filename>@SPECIAL_SYSLOG_SERVICE@</filename>
- (or a socket unit that
- activates this
- service).</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>systemd-initctl.service</filename></term>
+ <term><filename>nss-lookup.target</filename></term>
<listitem>
- <para>This provides
- compatibility with the SysV
- /dev/initctl file system FIFO
- for communication with the
- init system.</para>
- <para>This is a
- socket-activated service, see
- <filename>system-initctl.socket</filename>.</para>
+ <para>A target that should be
+ used as synchronization point
+ for all host/network name
+ service lookups. Note that
+ this is independent of
+ user/group name lookups for
+ which
+ <filename>nss-user-lookup.target</filename>
+ should be used. systemd
+ automatically adds
+ dependencies of type
+ <varname>After=</varname> for
+ this target unit to all SysV
+ init script service units with
+ an LSB header referring to the
+ <literal>$named</literal>
+ facility.</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>systemd-initctl.socket</filename></term>
+ <term><filename>nss-user-lookup.target</filename></term>
<listitem>
- <para>Socket activation unit
- for
- <filename>system-initctl.service</filename>.</para>
+ <para>A target that should be
+ used as synchronization point
+ for all user/group name
+ service lookups. Note that
+ this is independent of
+ host/network name lookups for
+ which
+ <filename>nss-lookup.target</filename>
+ should be used. </para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>systemd-logger.service</filename></term>
+ <term><filename>remote-fs-pre.target</filename></term>
<listitem>
- <para>This is internally used
- by systemd to provide syslog
- logging to the processes it
- maintains.</para>
- <para>This is a
- socket-activated service, see
- <filename>system-logger.socket</filename>.</para>
+ <para>This target unit is
+ automatically ordered before
+ all remote mount point units
+ (see above). It can be used to
+ run certain units before the
+ remote mounts are
+ established. Note that this
+ unit is generally not part of
+ the initial transaction,
+ unless the unit that wants to
+ be ordered before all remote
+ mounts pulls it in via a
+ <varname>Wants=</varname> type
+ dependency. If the unit wants
+ to be pulled in by the first
+ remote mount showing up it
+ should use
+ <filename>network-online.target</filename>
+ (see above).</para>
+
+ <para>Again, this target unit
+ is <emphasis>not</emphasis>
+ suitable for pulling in other
+ units, it is only useful for
+ ordering.</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><filename>systemd-logger.socket</filename></term>
+ <term><filename>rpcbind.target</filename></term>
<listitem>
- <para>Socket activation unit
- for
- <filename>system-logger.service</filename>. systemd
- will automatically add
- dependencies of types Requires
- and After to all units that
- have been configured for
- stdout or stderr to be
- connected to syslog or the
- kernel log buffer.</para>
+ <para>systemd automatically
+ adds dependencies of type
+ <varname>After=</varname> for
+ this target unit to all SysV
+ init script service units with
+ an LSB header referring to the
+ <literal>$portmap</literal>
+ facility.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><filename>time-sync.target</filename></term>
+ <listitem>
+ <para>systemd automatically
+ adds dependencies of type
+ <varname>After=</varname> for
+ this target unit to all SysV
+ init script service units with
+ an LSB header referring to the
+ <literal>$time</literal>
+ facility.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
- <title>Special Session Units</title>
+ <title>Special User Units</title>
- <para>When systemd runs as a service instance, the
+ <para>When systemd runs as a user instance, the
following special units are available, which have
similar definitions as their system counterparts:
<filename>default.target</filename>,
- <filename>local-fs.target</filename>,
- <filename>remote-fs.target</filename>,
<filename>shutdown.target</filename>,
<filename>sockets.target</filename>,
- <filename>swap.target</filename>.</para>
+ <filename>timers.target</filename>,
+ <filename>paths.target</filename>,
+ <filename>bluetooth.target</filename>,
+ <filename>printer.target</filename>,
+ <filename>smartcard.target</filename>,
+ <filename>sound.target</filename>.</para>
+
+ <para>In addition the following special unit is
+ understood only when systemd runs as service instance:</para>
+
+ <variablelist>
+ <varlistentry>
+ <term><filename>exit.target</filename></term>
+ <listitem>
+ <para>A special service unit
+ for shutting down the
+ user service manager.</para>
+
+ <para>Applications wanting to
+ terminate the user service
+ manager should start this
+ unit. If systemd receives
+ <constant>SIGTERM</constant> or <constant>SIGINT</constant> when running
+ as user service daemon it will
+ start this unit.</para>
+
+ <para>Normally, this pulls in
+ <filename>shutdown.target</filename>
+ which in turn should be
+ conflicted by all units that
+ want to be shut down on
+ user service manager exit.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Special Slice Units</title>
+
+ <para>There are four <literal>.slice</literal> units
+ which form the basis of the hierarchy for assignment
+ of resources for services, users, and virtual machines
+ or containers.</para>
+
+ <variablelist>
+ <varlistentry>
+ <term><filename>-.slice</filename></term>
+ <listitem>
+ <para>The root slice is the
+ root of the hierarchy. It
+ usually does not contain units
+ directly, but may be used to
+ set defaults for the whole
+ tree.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><filename>system.slice</filename></term>
+ <listitem>
+ <para>By default, all services
+ services started by
+ <command>systemd</command> are
+ found in this slice.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><filename>user.slice</filename></term>
+ <listitem>
+ <para>By default, all user
+ processes and services started
+ on behalf of the user,
+ including the per-user systemd
+ instance are found in this
+ slice.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><filename>machine.slice</filename></term>
+ <listitem>
+ <para>By defalt, all virtual
+ machines and containers
+ registered with
+ <command>systemd-machined</command>
+ are found in this slice.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
- <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</para>
</refsect1>
~ianmdlvl / elogind.git / blobdiff