mirror of
https://github.com/systemd/systemd.git
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5aded36978
It is annoying when we have dead links on fd.o. Add project='man-pages|die-net|archlinux' to <citerefentry>-ies. In generated html, add external links to http://man7.org/linux/man-pages/man, http://linux.die.net/man/, https://www.archlinux.org/. By default, pages in sections 2 and 4 go to man7, since Michael Kerrisk is the autorative source on kernel related stuff. The rest of links goes to linux.die.net, because they have the manpages. Except for the pacman stuff, since it seems to be only available from archlinux.org. Poor gummiboot gets no link, because gummitboot(8) ain't to be found on the net. According to common wisdom, that would mean that it does not exist. But I have seen Kay using it, so I know it does, and deserves to be found. Can somebody be nice and put it up somewhere?
1165 lines
65 KiB
XML
1165 lines
65 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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-->
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<refentry id="systemd.special">
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<refentryinfo>
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<title>systemd.special</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>systemd.special</refentrytitle>
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<manvolnum>7</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>systemd.special</refname>
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<refpurpose>Special systemd units</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<para><filename>basic.target</filename>,
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<filename>bluetooth.target</filename>,
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<filename>ctrl-alt-del.target</filename>,
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<filename>cryptsetup.target</filename>,
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<filename>cryptsetup-pre.target</filename>,
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<filename>dbus.service</filename>,
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<filename>dbus.socket</filename>,
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<filename>default.target</filename>,
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<filename>display-manager.service</filename>,
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<filename>emergency.target</filename>,
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<filename>exit.target</filename>,
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<filename>final.target</filename>,
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<filename>getty.target</filename>,
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<filename>graphical.target</filename>,
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<filename>halt.target</filename>,
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<filename>hibernate.target</filename>,
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<filename>hybrid-sleep.target</filename>,
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<filename>initrd-fs.target</filename>,
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<filename>kbrequest.target</filename>,
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<filename>kexec.target</filename>,
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<filename>local-fs.target</filename>,
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<filename>local-fs-pre.target</filename>,
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<filename>multi-user.target</filename>,
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<filename>network.target</filename>,
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<filename>network-online.target</filename>,
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<filename>network-pre.target</filename>,
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<filename>nss-lookup.target</filename>,
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<filename>nss-user-lookup.target</filename>,
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<filename>paths.target</filename>,
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<filename>poweroff.target</filename>,
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<filename>printer.target</filename>,
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<filename>reboot.target</filename>,
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<filename>remote-fs.target</filename>,
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<filename>remote-fs-pre.target</filename>,
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<filename>rescue.target</filename>,
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<filename>initrd-root-fs.target</filename>,
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<filename>rpcbind.target</filename>,
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<filename>runlevel2.target</filename>,
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<filename>runlevel3.target</filename>,
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<filename>runlevel4.target</filename>,
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<filename>runlevel5.target</filename>,
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<filename>shutdown.target</filename>,
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<filename>sigpwr.target</filename>,
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<filename>sleep.target</filename>,
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<filename>smartcard.target</filename>,
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<filename>sockets.target</filename>,
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<filename>sound.target</filename>,
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<filename>suspend.target</filename>,
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<filename>swap.target</filename>,
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<filename>sysinit.target</filename>,
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<filename>syslog.socket</filename>,
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<filename>system-update.target</filename>,
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<filename>time-sync.target</filename>,
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<filename>timers.target</filename>,
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<filename>umount.target</filename>,
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<filename>-.slice</filename>,
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<filename>system.slice</filename>,
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<filename>user.slice</filename>,
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<filename>machine.slice</filename></para>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>A few units are treated specially by
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systemd. They have special internal semantics and
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cannot be renamed.</para>
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</refsect1>
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<refsect1>
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<title>Special System Units</title>
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<variablelist>
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<varlistentry>
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<term><filename>basic.target</filename></term>
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<listitem>
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<para>A special target unit
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covering basic boot-up.</para>
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<para>systemd automatically
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adds dependencies of the types
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<varname>Requires=</varname>
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and <varname>After=</varname>
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for this target unit to all
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services (except for those
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with
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<varname>DefaultDependencies=no</varname>).</para>
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<para>Usually this should
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pull-in all mount points, swap
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devices, sockets, timers, and
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path units and other basic
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initialization necessary for
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general purpose
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daemons.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><filename>ctrl-alt-del.target</filename></term>
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<listitem>
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<para>systemd starts this
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target whenever
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Control+Alt+Del is pressed on
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the console. Usually this
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should be aliased (symlinked)
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to
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<filename>reboot.target</filename>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><filename>cryptsetup.target</filename></term>
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<listitem>
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<para>A target that pulls in
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setup services for all
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encrypted block
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devices.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><filename>dbus.service</filename></term>
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<listitem>
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<para>A special unit for the
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D-Bus bus daemon. As soon as
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this service is fully started
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up systemd will connect to it
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and register its
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service.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><filename>dbus.socket</filename></term>
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<listitem>
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<para>A special unit for the
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D-Bus system bus socket. All
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units with
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<varname>Type=dbus</varname>
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automatically gain a
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dependency on this
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unit.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><filename>default.target</filename></term>
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<listitem>
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<para>The default unit systemd
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starts at bootup. Usually this
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should be aliased (symlinked)
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to
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<filename>multi-user.target</filename>
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or
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<filename>graphical.target</filename>.</para>
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<para>The default unit systemd
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starts at bootup can be
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overridden with the
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<varname>systemd.unit=</varname>
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kernel command line option.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><filename>display-manager.service</filename></term>
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<listitem>
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<para>The display manager
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service. Usually this should
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be aliased (symlinked) to
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<filename>gdm.service</filename>
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or a similar display manager
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service.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><filename>emergency.target</filename></term>
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<listitem>
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<para>A special target unit
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that starts an emergency
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shell on the main
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console. This unit is supposed
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to be used with the kernel
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command line option
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<varname>systemd.unit=</varname>
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and has otherwise little use.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><filename>final.target</filename></term>
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<listitem>
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<para>A special target unit
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that is used during the
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shutdown logic and may be used
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to pull in late services after
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all normal services are
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already terminated and all
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mounts unmounted.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><filename>getty.target</filename></term>
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<listitem>
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<para>A special target unit
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that pulls in statically
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configured local TTY
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<filename>getty</filename>
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instances.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><filename>graphical.target</filename></term>
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<listitem>
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<para>A special target unit
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for setting up a graphical
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login screen. This pulls in
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<filename>multi-user.target</filename>.</para>
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<para>Units that are needed
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for graphical logins shall add
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<varname>Wants=</varname>
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dependencies for their unit to
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this unit (or
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<filename>multi-user.target</filename>)
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during installation. This is
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best configured via
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<varname>WantedBy=graphical.target</varname>
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in the unit's
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<literal>[Install]</literal>
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section.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><filename>hibernate.target</filename></term>
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<listitem>
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<para>A special target unit
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for hibernating the
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|
system. This pulls in
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<filename>sleep.target</filename>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
|
|
<term><filename>hybrid-sleep.target</filename></term>
|
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<listitem>
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<para>A special target unit
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for hibernating and suspending the
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system at the same time. This pulls in
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<filename>sleep.target</filename>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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|
<term><filename>halt.target</filename></term>
|
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<listitem>
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<para>A special target unit
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for shutting down and halting
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the system. Note that this
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|
target is distinct from
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|
<filename>poweroff.target</filename>
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|
in that it generally really
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just halts the system rather
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|
than powering it down.</para>
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<para>Applications wanting to
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halt the system should start
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this unit.</para>
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|
</listitem>
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|
</varlistentry>
|
|
<varlistentry>
|
|
<term><filename>initrd-fs.target</filename></term>
|
|
<listitem>
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|
<para><citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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|
automatically adds
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|
dependencies of type
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|
<varname>Before=</varname> to
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|
<filename>sysroot-usr.mount</filename>
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|
and all mount points found in
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|
<filename>/etc/fstab</filename>
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|
that have
|
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<option>x-initrd.mount</option>
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|
and not have <option>noauto</option>
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|
mount options set.</para>
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|
</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>
|
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|
|
<para>Applications wanting to
|
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reboot the system with kexec should start
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this unit.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><filename>local-fs.target</filename></term>
|
|
<listitem>
|
|
<para><citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
|
automatically adds
|
|
dependencies of type
|
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<varname>Before=</varname> to
|
|
all mount units that refer to
|
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local mount points for this
|
|
target unit. In addition, it
|
|
adds dependencies of type
|
|
<varname>Wants=</varname> to
|
|
this target unit for those
|
|
mounts listed in
|
|
<filename>/etc/fstab</filename>
|
|
that have the
|
|
<option>auto</option> mount
|
|
option set.</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 <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-online.target</filename></term>
|
|
<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>paths.target</filename></term>
|
|
<listitem>
|
|
<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>
|
|
<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>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
|
|
<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>
|
|
<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>initrd-root-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
|
|
the
|
|
<filename>sysroot.mount</filename>
|
|
unit, which is generated from
|
|
the kernel command line.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<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>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>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 <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>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>sockets.target</filename></term>
|
|
<listitem>
|
|
<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>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>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<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 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>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 mount unit, which is
|
|
implicitly done when
|
|
<varname>DefaultDependencies=yes</varname>
|
|
is set (the default).</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
</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>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>
|
|
|
|
<para>This may be used to pull
|
|
in printer management
|
|
daemons dynamically when
|
|
printer hardware is
|
|
found.</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>
|
|
|
|
<para>This may be used to pull
|
|
in smartcard management
|
|
daemons dynamically when
|
|
smartcard hardware is
|
|
found.</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>
|
|
|
|
<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>cryptsetup-pre.target</filename></term>
|
|
<listitem>
|
|
<para>This passive target unit
|
|
may be pulled in by services
|
|
that want to run before any
|
|
encrypted block device is set
|
|
up. All encrypted block
|
|
devices are set up after this
|
|
target has been reached. Since
|
|
the shutdown order is
|
|
implicitly the reverse
|
|
start-up order between units,
|
|
this target is particularly
|
|
useful to ensure that a
|
|
service is shut down only
|
|
after all encrypted block
|
|
devices are fully
|
|
stopped.</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>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. It is hence useful
|
|
when writing service files
|
|
that require network access on
|
|
shutdown, which should order
|
|
themselves after this target,
|
|
but not pull it in. 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
|
|
<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>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><filename>network-pre.target</filename></term>
|
|
<listitem>
|
|
<para>This passive target unit
|
|
may be pulled in by services
|
|
that want to run before any
|
|
network is set up, for example
|
|
for the purpose of setting up a
|
|
firewall. All network
|
|
management software orders
|
|
itself after this target, but
|
|
does not pull it in.</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. All services
|
|
for which the availability of
|
|
full host/network name
|
|
resolution is essential should
|
|
be ordered after this target,
|
|
but not pull it in. 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>$named</literal>
|
|
facility.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><filename>nss-user-lookup.target</filename></term>
|
|
<listitem>
|
|
<para>A target that should be
|
|
used as synchronization point
|
|
for all user/group name
|
|
service lookups. Note that
|
|
this is independent of
|
|
host/network name lookups for
|
|
which
|
|
<filename>nss-lookup.target</filename>
|
|
should be used. All services
|
|
for which the availability of
|
|
the full user/group database is
|
|
essential should be ordered
|
|
after this target, but not
|
|
pull it in. Note that system
|
|
users are always resolvable,
|
|
and hence do not require any
|
|
special ordering against this
|
|
target.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><filename>remote-fs-pre.target</filename></term>
|
|
<listitem>
|
|
<para>This target unit is
|
|
automatically ordered before
|
|
all remote mount point units
|
|
(see above). It can be used to
|
|
run certain units before the
|
|
remote mounts are
|
|
established. Note that this
|
|
unit is generally not part of
|
|
the initial transaction,
|
|
unless the unit that wants to
|
|
be ordered before all remote
|
|
mounts pulls it in via a
|
|
<varname>Wants=</varname> type
|
|
dependency. If the unit wants
|
|
to be pulled in by the first
|
|
remote mount showing up, it
|
|
should use
|
|
<filename>network-online.target</filename>
|
|
(see above).</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><filename>rpcbind.target</filename></term>
|
|
<listitem>
|
|
<para>The portmapper/rpcbind
|
|
pulls in this target and
|
|
orders itself before it, to
|
|
indicate its
|
|
availability. systemd
|
|
automatically adds
|
|
dependencies of type
|
|
<varname>After=</varname> for
|
|
this target unit to all SysV
|
|
init script service units with
|
|
an LSB header referring to the
|
|
<literal>$portmap</literal>
|
|
facility.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><filename>time-sync.target</filename></term>
|
|
<listitem>
|
|
<para>Services responsible for
|
|
synchronizing the system clock
|
|
from a remote source (such as
|
|
NTP client implementations)
|
|
should pull in this target and
|
|
order themselves before
|
|
it. All services where correct
|
|
time is essential should be
|
|
ordered after this unit, but
|
|
not pull it in. 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 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>,
|
|
<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 default, 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</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 project='man-pages'><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|