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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"

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<refentry id="systemd.special">

<refentryinfo>

<title>systemd.special</title>

<productname>systemd</productname>

<authorgroup>

<author>

<contrib>Developer</contrib>

<firstname>Lennart</firstname>

<surname>Poettering</surname>

<email>lennart@poettering.net</email>

</author>

</authorgroup>

</refentryinfo>

<refmeta>

<refentrytitle>systemd.special</refentrytitle>

<manvolnum>7</manvolnum>

</refmeta>

<refnamediv>

<refname>systemd.special</refname>

<refpurpose>Special systemd units</refpurpose>

</refnamediv>

<refsynopsisdiv>

<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>hibernate.target</filename>,

<filename>http-daemon.target</filename>,

<filename>hybrid-sleep.target</filename>,

<filename>halt.target</filename>,

<filename>kbrequest.target</filename>,

<filename>kexec.target</filename>,

<filename>local-fs.target</filename>,

<filename>local-fs-pre.target</filename>,

<filename>mail-transfer-agent.target</filename>,

<filename>multi-user.target</filename>,

<filename>network.target</filename>,

<filename>nss-lookup.target</filename>,

<filename>nss-user-lookup.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>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>syslog.target</filename>,

<filename>system-update.target</filename>,

<filename>time-sync.target</filename>,

<filename>umount.target</filename></para>

</refsynopsisdiv>

<refsect1>

<title>Description</title>

<para>A few units are treated specially by

systemd. They have special internal semantics and

cannot be renamed.</para>

</refsect1>

<refsect1>

<title>Special System Units</title>

<variablelist>

<varlistentry>

<term><filename>basic.target</filename></term>

<listitem>

<para>A special target unit

covering early 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>Usually this should pull-in

all sockets, mount points,

swap devices and other basic

initialization necessary for

the general purpose

daemons. Most normal daemons

should have dependencies of

type After and Requires on

this unit.</para>

</listitem>

</varlistentry>

<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>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>ctrl-alt-del.target</filename></term>

<listitem>

<para>systemd starts this

target whenever

Control+Alt+Del is pressed on

the console. Usually this

should be aliased (symlinked)

to

<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 system bus. 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

<literal>Type=dbus</literal>

automatically gain a

dependency on this

unit.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>default.target</filename></term>

<listitem>

<para>The default unit systemd

starts at bootup. Usually this

should be aliased (symlinked)

to

<filename>multi-user.target</filename>

or

<filename>graphical.target</filename>.</para>

<para>The default unit systemd

starts at bootup can be

overridden with the

<varname>systemd.unit=</varname>

kernel command line option.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>display-manager.service</filename></term>

<listitem>

<para>The display manager

service. Usually this should

be aliased (symlinked) to

<filename>gdm.service</filename>

or a similar display manager

service.</para>

<para>systemd automatically

adds dependencies of type

After for this target unit to

all SysV init script service

units with a LSB header

referring to the

<literal>$x-display-manager</literal>

facility, for compatibility

with Debian.</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.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 all local TTY

<filename>getty</filename> instances.

</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>graphical.target</filename></term>

<listitem>

<para>A special target unit

for setting up a graphical

login screen. This pulls in

<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

<filename>multi-user.target</filename>)

during installation.</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>http-daemon.target</filename></term>

<listitem>

<para>A target for pulling in

an HTTP server if there is

any.</para>

<para>systemd automatically

adds dependencies of type

After for this target unit to

all SysV init script service

units with a LSB header

referring to the

<literal>$httpd</literal>

facility.</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>

<para>Applications wanting to

halt the system should start

this unit.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>kbrequest.target</filename></term>

<listitem>

<para>systemd starts this

target whenever Alt+ArrowUp is

pressed on the console. This

is a good candidate to be

aliased (symlinked) to

<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

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

this target unit for those

mounts listed in

<filename>/etc/fstab</filename>

that have the

<option>auto</option> and

<option>comment=systemd.mount</option>

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>

</listitem>

</varlistentry>

<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>mail-transfer-agent.target</filename></term>

<listitem>

<para>The mail transfer agent

(MTA) service. Usually this

should pull-in all units

necessary for

sending/receiving mails on the

local host.</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>$mail-transfer-agent</literal>

or

<literal>$mail-transport-agent</literal>

facilities, for compatibility

with Debian.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>multi-user.target</filename></term>

<listitem>

<para>A special target unit

for setting up a multi-user

system (non-graphical). This

is pulled in by

<filename>graphical.target</filename>.</para>

<para>Units that are needed

for a multi-user system shall

add Wants dependencies to

this unit for their unit during

installation.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>network.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>

</varlistentry>

<varlistentry>

<term><filename>nss-lookup.target</filename></term>

<listitem>

<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 After 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>nss-user-lookup.target</filename></term>

<listitem>

<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>poweroff.target</filename></term>

<listitem>

<para>A special target unit

for shutting down and powering off the system.</para>

<para>Applications wanting to

power off the system should start

this unit.</para>

<para><filename>runlevel0.target</filename>

is an alias for this target

unit, for compatibility with SysV.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>printer.target</filename></term>

<listitem>

<para>This target is started

automatically as soon as a

printer is plugged in or

becomes available at

boot.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>reboot.target</filename></term>

<listitem>

<para>A special target unit

for shutting down and rebooting the system.</para>

<para>Applications wanting to

reboot the system should start

this unit.</para>

<para><filename>runlevel6.target</filename>

is an alias for this target

unit, for compatibility with SysV.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>remote-fs.target</filename></term>

<listitem>

<para>Similar to

<filename>local-fs.target</filename>,

but for remote mount

points.</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>$remote_fs</literal>

facility.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>remote-fs-pre.target</filename></term>

<listitem>

<para>This target unit is

automatically ordered before

all remote mount points marked

with <option>auto</option>

(see above). It can be used to

execute certain units before

all remote mounts.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>rescue.target</filename></term>

<listitem>

<para>A special target unit

for setting up the base system

and a rescue shell.</para>

<para><filename>runlevel1.target</filename>

is an alias for this target

unit, for compatibility with SysV.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>rpcbind.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>$portmap</literal>

facility.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>runlevel2.target</filename></term>

<listitem>

<para>This is a target that is

called whenever 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>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>runlevel3.target</filename></term>

<listitem>

<para>This is a target that is

called whenever 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>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>runlevel4.target</filename></term>

<listitem>

<para>This is a target that is

called whenever 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>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>runlevel5.target</filename></term>

<listitem>

<para>This is a target that is

called whenever 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>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>shutdown.target</filename></term>

<listitem>

<para>A special target unit

that terminates the services

on system shutdown.</para>

<para>Services that shall be

terminated on system shutdown

shall add Conflicts

dependencies to this unit for

their service unit, which is

implicitly done when

<varname>DefaultDependencies=yes</varname>

is set (the default).</para>

<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>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>sigpwr.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>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>sleep.target</filename></term>

<listitem>

<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>smartcard.target</filename></term>

<listitem>

<para>This target is started

automatically as soon as a

smartcard controller is

plugged in or becomes

available at boot.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>sockets.target</filename></term>

<listitem>

<para>A special target unit

that sets up all service

sockets.</para>

<para>Services that can be

socket-activated shall add

Wants dependencies to this

unit for their socket unit

during installation.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>sound.target</filename></term>

<listitem>

<para>This target is started

automatically as soon as a

sound card is plugged in or

becomes available at

boot.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>suspend.target</filename></term>

<listitem>

<para>A special target unit

for suspending the

system. This pulls in

<filename>sleep.target</filename>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>swap.target</filename></term>

<listitem>

<para>Similar to

<filename>local-fs.target</filename>, but for swap

partitions and swap

files.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>sysinit.target</filename></term>

<listitem>

<para>A special target unit

covering early boot-up scripts.</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>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>syslog.socket</filename></term>

<listitem>

<para>The socket unit where

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>syslog.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>$syslog</literal>

facility.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><filename>system-update.target</filename></term>

<listitem>

<para>A special target unit

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>time-sync.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>

</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 mount unit, which is

implicitly done when

<varname>DefaultDependencies=yes</varname>

is set (the default).</para>

</listitem>

</varlistentry>

</variablelist>

</refsect1>

<refsect1>

<title>Special User Units</title>

<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>shutdown.target</filename>,

<filename>sockets.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

SIGTERM or SIGINT 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>See Also</title>

<para>

<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>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>

</para>

</refsect1>

</refentry>