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| 19 | <a href="systemd.directives.html">Directives </a>· | |
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22 | <a href="../libudev/index.html">gudev </a><span style="float:right">systemd 219</span><hr><div class="refentry"><a name="systemd.special"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>systemd.special — Special systemd units</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><p><code class="filename">basic.target</code>, |
| 23 | <code class="filename">bluetooth.target</code>, | |
| 24 | <code class="filename">ctrl-alt-del.target</code>, | |
| 25 | <code class="filename">cryptsetup.target</code>, | |
| 26 | <code class="filename">cryptsetup-pre.target</code>, | |
| 27 | <code class="filename">dbus.service</code>, | |
| 28 | <code class="filename">dbus.socket</code>, | |
| 29 | <code class="filename">default.target</code>, | |
| 30 | <code class="filename">display-manager.service</code>, | |
| 31 | <code class="filename">emergency.target</code>, | |
| 32 | <code class="filename">exit.target</code>, | |
| 33 | <code class="filename">final.target</code>, | |
| 34 | <code class="filename">getty.target</code>, | |
| 35 | <code class="filename">graphical.target</code>, | |
| 36 | <code class="filename">halt.target</code>, | |
| 37 | <code class="filename">hibernate.target</code>, | |
| 38 | <code class="filename">hybrid-sleep.target</code>, | |
| 39 | <code class="filename">initrd-fs.target</code>, | |
| 40 | <code class="filename">kbrequest.target</code>, | |
| 41 | <code class="filename">kexec.target</code>, | |
| 42 | <code class="filename">local-fs.target</code>, | |
| 43 | <code class="filename">local-fs-pre.target</code>, | |
| 44 | <code class="filename">multi-user.target</code>, | |
| 45 | <code class="filename">network.target</code>, | |
| 46 | <code class="filename">network-online.target</code>, | |
| 47 | <code class="filename">network-pre.target</code>, | |
| 48 | <code class="filename">nss-lookup.target</code>, | |
| 49 | <code class="filename">nss-user-lookup.target</code>, | |
| 50 | <code class="filename">paths.target</code>, | |
| 51 | <code class="filename">poweroff.target</code>, | |
| 52 | <code class="filename">printer.target</code>, | |
| 53 | <code class="filename">reboot.target</code>, | |
| 54 | <code class="filename">remote-fs.target</code>, | |
| 55 | <code class="filename">remote-fs-pre.target</code>, | |
| 56 | <code class="filename">rescue.target</code>, | |
| 57 | <code class="filename">initrd-root-fs.target</code>, | |
| 58 | <code class="filename">rpcbind.target</code>, | |
| 59 | <code class="filename">runlevel2.target</code>, | |
| 60 | <code class="filename">runlevel3.target</code>, | |
| 61 | <code class="filename">runlevel4.target</code>, | |
| 62 | <code class="filename">runlevel5.target</code>, | |
| 63 | <code class="filename">shutdown.target</code>, | |
| 64 | <code class="filename">sigpwr.target</code>, | |
| 65 | <code class="filename">sleep.target</code>, | |
| 66 | <code class="filename">smartcard.target</code>, | |
| 67 | <code class="filename">sockets.target</code>, | |
| 68 | <code class="filename">sound.target</code>, | |
| 69 | <code class="filename">suspend.target</code>, | |
| 70 | <code class="filename">swap.target</code>, | |
| 71 | <code class="filename">sysinit.target</code>, | |
| 72 | <code class="filename">syslog.socket</code>, | |
| 73 | <code class="filename">system-update.target</code>, | |
| 74 | <code class="filename">time-sync.target</code>, | |
| 75 | <code class="filename">timers.target</code>, | |
| 76 | <code class="filename">umount.target</code>, | |
| 77 | <code class="filename">-.slice</code>, | |
| 78 | <code class="filename">system.slice</code>, | |
| 79 | <code class="filename">user.slice</code>, | |
| 80 | <code class="filename">machine.slice</code></p></div><div class="refsect1"><a name="idm140275576377296"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description">¶</a></h2><p>A few units are treated specially by systemd. They have | |
| 81 | special internal semantics and cannot be renamed.</p></div><div class="refsect1"><a name="idm140275576375984"></a><h2 id="Special System Units">Special System Units<a class="headerlink" title="Permalink to this headline" href="#Special%20System%20Units">¶</a></h2><div class="variablelist"><dl class="variablelist"><dt id="basic.target"><span class="term"><code class="filename">basic.target</code></span><a class="headerlink" title="Permalink to this term" href="#basic.target">¶</a></dt><dd><p>A special target unit covering basic boot-up.</p><p>systemd automatically adds dependencies of the types | |
| 82 | <code class="varname">Requires=</code> and <code class="varname">After=</code> | |
| 83 | for this target unit to all services (except for those with | |
| 84 | <code class="varname">DefaultDependencies=no</code>).</p><p>Usually this should pull-in all mount points, swap | |
| 85 | devices, sockets, timers, and path units and other basic | |
| 86 | initialization necessary for general purpose daemons.</p></dd><dt id="ctrl-alt-del.target"><span class="term"><code class="filename">ctrl-alt-del.target</code></span><a class="headerlink" title="Permalink to this term" href="#ctrl-alt-del.target">¶</a></dt><dd><p>systemd starts this target whenever Control+Alt+Del is | |
| 87 | pressed on the console. Usually this should be aliased | |
| 88 | (symlinked) to <code class="filename">reboot.target</code>.</p></dd><dt id="cryptsetup.target"><span class="term"><code class="filename">cryptsetup.target</code></span><a class="headerlink" title="Permalink to this term" href="#cryptsetup.target">¶</a></dt><dd><p>A target that pulls in setup services for all | |
| 89 | encrypted block devices.</p></dd><dt id="dbus.service"><span class="term"><code class="filename">dbus.service</code></span><a class="headerlink" title="Permalink to this term" href="#dbus.service">¶</a></dt><dd><p>A special unit for the D-Bus bus daemon. As soon as | |
| 90 | this service is fully started up systemd will connect to it | |
| 91 | and register its service.</p></dd><dt id="dbus.socket"><span class="term"><code class="filename">dbus.socket</code></span><a class="headerlink" title="Permalink to this term" href="#dbus.socket">¶</a></dt><dd><p>A special unit for the D-Bus system bus socket. All | |
| 92 | units with <code class="varname">Type=dbus</code> automatically gain a | |
| 93 | dependency on this unit.</p></dd><dt id="default.target"><span class="term"><code class="filename">default.target</code></span><a class="headerlink" title="Permalink to this term" href="#default.target">¶</a></dt><dd><p>The default unit systemd starts at bootup. Usually | |
| 94 | this should be aliased (symlinked) to | |
| 95 | <code class="filename">multi-user.target</code> or | |
| 96 | <code class="filename">graphical.target</code>.</p><p>The default unit systemd starts at bootup can be | |
| 97 | overridden with the <code class="varname">systemd.unit=</code> kernel | |
| 98 | command line option.</p></dd><dt id="display-manager.service"><span class="term"><code class="filename">display-manager.service</code></span><a class="headerlink" title="Permalink to this term" href="#display-manager.service">¶</a></dt><dd><p>The display manager service. Usually this should be | |
| 99 | aliased (symlinked) to <code class="filename">gdm.service</code> or a | |
| 100 | similar display manager service.</p></dd><dt id="emergency.target"><span class="term"><code class="filename">emergency.target</code></span><a class="headerlink" title="Permalink to this term" href="#emergency.target">¶</a></dt><dd><p>A special target unit that starts an emergency shell | |
| 101 | on the main console. This unit is supposed to be used with | |
| 102 | the kernel command line option | |
| 103 | <code class="varname">systemd.unit=</code> and has otherwise little | |
| 104 | use. | |
| 105 | </p></dd><dt id="final.target"><span class="term"><code class="filename">final.target</code></span><a class="headerlink" title="Permalink to this term" href="#final.target">¶</a></dt><dd><p>A special target unit that is used during the shutdown | |
| 106 | logic and may be used to pull in late services after all | |
| 107 | normal services are already terminated and all mounts | |
| 108 | unmounted. | |
| 109 | </p></dd><dt id="getty.target"><span class="term"><code class="filename">getty.target</code></span><a class="headerlink" title="Permalink to this term" href="#getty.target">¶</a></dt><dd><p>A special target unit that pulls in statically | |
| 110 | configured local TTY <code class="filename">getty</code> instances. | |
| 111 | </p></dd><dt id="graphical.target"><span class="term"><code class="filename">graphical.target</code></span><a class="headerlink" title="Permalink to this term" href="#graphical.target">¶</a></dt><dd><p>A special target unit for setting up a graphical login | |
| 112 | screen. This pulls in | |
| 113 | <code class="filename">multi-user.target</code>.</p><p>Units that are needed for graphical logins shall add | |
| 114 | <code class="varname">Wants=</code> dependencies for their unit to | |
| 115 | this unit (or <code class="filename">multi-user.target</code>) during | |
| 116 | installation. This is best configured via | |
| 117 | <code class="varname">WantedBy=graphical.target</code> in the unit's | |
| 118 | "<code class="literal">[Install]</code>" section.</p></dd><dt id="hibernate.target"><span class="term"><code class="filename">hibernate.target</code></span><a class="headerlink" title="Permalink to this term" href="#hibernate.target">¶</a></dt><dd><p>A special target unit for hibernating the system. This | |
| 119 | pulls in <code class="filename">sleep.target</code>.</p></dd><dt id="hybrid-sleep.target"><span class="term"><code class="filename">hybrid-sleep.target</code></span><a class="headerlink" title="Permalink to this term" href="#hybrid-sleep.target">¶</a></dt><dd><p>A special target unit for hibernating and suspending | |
| 120 | the system at the same time. This pulls in | |
| 121 | <code class="filename">sleep.target</code>.</p></dd><dt id="halt.target"><span class="term"><code class="filename">halt.target</code></span><a class="headerlink" title="Permalink to this term" href="#halt.target">¶</a></dt><dd><p>A special target unit for shutting down and halting | |
| 122 | the system. Note that this target is distinct from | |
| 123 | <code class="filename">poweroff.target</code> in that it generally | |
| 124 | really just halts the system rather than powering it | |
| 125 | down.</p><p>Applications wanting to halt the system should start | |
| 126 | this unit.</p></dd><dt id="initrd-fs.target"><span class="term"><code class="filename">initrd-fs.target</code></span><a class="headerlink" title="Permalink to this term" href="#initrd-fs.target">¶</a></dt><dd><p><a href="systemd-fstab-generator.html"><span class="citerefentry"><span class="refentrytitle">systemd-fstab-generator</span>(3)</span></a> | |
| 127 | automatically adds dependencies of type | |
| 128 | <code class="varname">Before=</code> to | |
| 129 | <code class="filename">sysroot-usr.mount</code> and all mount points | |
| 130 | found in <code class="filename">/etc/fstab</code> that have | |
| 131 | <code class="option">x-initrd.mount</code> and not have | |
| 132 | <code class="option">noauto</code> mount options set.</p></dd><dt id="kbrequest.target"><span class="term"><code class="filename">kbrequest.target</code></span><a class="headerlink" title="Permalink to this term" href="#kbrequest.target">¶</a></dt><dd><p>systemd starts this target whenever Alt+ArrowUp is | |
| 133 | pressed on the console. This is a good candidate to be | |
| 134 | aliased (symlinked) to | |
| 135 | <code class="filename">rescue.target</code>.</p></dd><dt id="kexec.target"><span class="term"><code class="filename">kexec.target</code></span><a class="headerlink" title="Permalink to this term" href="#kexec.target">¶</a></dt><dd><p>A special target unit for shutting down and rebooting | |
| 136 | the system via kexec.</p><p>Applications wanting to reboot the system with kexec | |
| 137 | should start this unit.</p></dd><dt id="local-fs.target"><span class="term"><code class="filename">local-fs.target</code></span><a class="headerlink" title="Permalink to this term" href="#local-fs.target">¶</a></dt><dd><p><a href="systemd-fstab-generator.html"><span class="citerefentry"><span class="refentrytitle">systemd-fstab-generator</span>(3)</span></a> | |
| 138 | automatically adds dependencies of type | |
| 139 | <code class="varname">Before=</code> to all mount units that refer to | |
| 140 | local mount points for this target unit. In addition, it | |
| 141 | adds dependencies of type <code class="varname">Wants=</code> to this | |
| 142 | target unit for those mounts listed in | |
| 143 | <code class="filename">/etc/fstab</code> that have the | |
| 144 | <code class="option">auto</code> mount option set.</p></dd><dt id="multi-user.target"><span class="term"><code class="filename">multi-user.target</code></span><a class="headerlink" title="Permalink to this term" href="#multi-user.target">¶</a></dt><dd><p>A special target unit for setting up a multi-user | |
| 145 | system (non-graphical). This is pulled in by | |
| 146 | <code class="filename">graphical.target</code>.</p><p>Units that are needed for a multi-user system shall | |
| 147 | add <code class="varname">Wants=</code> dependencies for their unit to | |
| 148 | this unit during installation. This is best configured via | |
| 149 | <code class="varname">WantedBy=multi-user.target</code> in the unit's | |
| 150 | "<code class="literal">[Install]</code>" section.</p></dd><dt id="network-online.target"><span class="term"><code class="filename">network-online.target</code></span><a class="headerlink" title="Permalink to this term" href="#network-online.target">¶</a></dt><dd><p>Units that strictly require a configured network | |
| 151 | connection should pull in | |
| 152 | <code class="filename">network-online.target</code> (via a | |
| 153 | <code class="varname">Wants=</code> type dependency) and order | |
| 154 | themselves after it. This target unit is intended to pull in | |
| 155 | a service that delays further execution until the network is | |
| 156 | sufficiently set up. What precisely this requires is left to | |
| 157 | the implementation of the network managing service.</p><p>Note the distinction between this unit and | |
| 158 | <code class="filename">network.target</code>. This unit is an active | |
| 159 | unit (i.e. pulled in by the consumer rather than the | |
| 160 | provider of this functionality) and pulls in a service which | |
| 161 | possibly adds substantial delays to further execution. In | |
| 162 | contrast, <code class="filename">network.target</code> is a passive | |
| 163 | unit (i.e. pulled in by the provider of the functionality, | |
| 164 | rather than the consumer) that usually does not delay | |
| 165 | execution much. Usually, <code class="filename">network.target</code> | |
| 166 | is part of the boot of most systems, while | |
| 167 | <code class="filename">network-online.target</code> is not, except | |
| 168 | when at least one unit requires it. Also see <a class="ulink" href="http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget" target="_top">Running | |
| 169 | Services After the Network is up</a> for more | |
| 170 | information.</p><p>All mount units for remote network file systems | |
| 171 | automatically pull in this unit, and order themselves after | |
| 172 | it. Note that networking daemons that simply provide | |
| 173 | functionality to other hosts generally do not need to pull | |
| 174 | this in.</p></dd><dt id="paths.target"><span class="term"><code class="filename">paths.target</code></span><a class="headerlink" title="Permalink to this term" href="#paths.target">¶</a></dt><dd><p>A special target unit that sets up all path units (see | |
| 175 | <a href="systemd.path.html"><span class="citerefentry"><span class="refentrytitle">systemd.path</span>(5)</span></a> | |
| 176 | for details) that shall be active after boot.</p><p>It is recommended that path units installed by | |
| 177 | applications get pulled in via <code class="varname">Wants=</code> | |
| 178 | dependencies from this unit. This is best configured via a | |
| 179 | <code class="varname">WantedBy=paths.target</code> in the path unit's | |
| 180 | "<code class="literal">[Install]</code>" section.</p></dd><dt id="poweroff.target"><span class="term"><code class="filename">poweroff.target</code></span><a class="headerlink" title="Permalink to this term" href="#poweroff.target">¶</a></dt><dd><p>A special target unit for shutting down and powering | |
| 181 | off the system.</p><p>Applications wanting to power off the system should | |
| 182 | start this unit.</p><p><code class="filename">runlevel0.target</code> is an alias for | |
| 183 | this target unit, for compatibility with SysV.</p></dd><dt id="reboot.target"><span class="term"><code class="filename">reboot.target</code></span><a class="headerlink" title="Permalink to this term" href="#reboot.target">¶</a></dt><dd><p>A special target unit for shutting down and rebooting | |
| 184 | the system.</p><p>Applications wanting to reboot the system should start | |
| 185 | this unit.</p><p><code class="filename">runlevel6.target</code> is an alias for | |
| 186 | this target unit, for compatibility with SysV.</p></dd><dt id="remote-fs.target"><span class="term"><code class="filename">remote-fs.target</code></span><a class="headerlink" title="Permalink to this term" href="#remote-fs.target">¶</a></dt><dd><p>Similar to <code class="filename">local-fs.target</code>, but | |
| 187 | for remote mount points.</p><p>systemd automatically adds dependencies of type | |
| 188 | <code class="varname">After=</code> for this target unit to all SysV | |
| 189 | init script service units with an LSB header referring to | |
| 190 | the "<code class="literal">$remote_fs</code>" facility.</p></dd><dt id="rescue.target"><span class="term"><code class="filename">rescue.target</code></span><a class="headerlink" title="Permalink to this term" href="#rescue.target">¶</a></dt><dd><p>A special target unit for setting up the base system | |
| 191 | and a rescue shell.</p><p><code class="filename">runlevel1.target</code> is an alias for | |
| 192 | this target unit, for compatibility with SysV.</p></dd><dt id="initrd-root-fs.target"><span class="term"><code class="filename">initrd-root-fs.target</code></span><a class="headerlink" title="Permalink to this term" href="#initrd-root-fs.target">¶</a></dt><dd><p><a href="systemd-fstab-generator.html"><span class="citerefentry"><span class="refentrytitle">systemd-fstab-generator</span>(3)</span></a> | |
| 193 | automatically adds dependencies of type | |
| 194 | <code class="varname">Before=</code> to the | |
| 195 | <code class="filename">sysroot.mount</code> unit, which is generated | |
| 196 | from the kernel command line. | |
| 197 | </p></dd><dt id="runlevel2.target"><span class="term"><code class="filename">runlevel2.target</code>, </span><span class="term"><code class="filename">runlevel3.target</code>, </span><span class="term"><code class="filename">runlevel4.target</code>, </span><span class="term"><code class="filename">runlevel5.target</code></span><a class="headerlink" title="Permalink to this term" href="#runlevel2.target">¶</a></dt><dd><p>These are targets that are called whenever the SysV | |
| 198 | compatibility code asks for runlevel 2, 3, 4, 5, | |
| 199 | respectively. It is a good idea to make this an alias for | |
| 200 | (i.e. symlink to) <code class="filename">multi-user.target</code> | |
| 201 | (for runlevel 2) or <code class="filename">graphical.target</code> | |
| 202 | (the others).</p></dd><dt id="shutdown.target"><span class="term"><code class="filename">shutdown.target</code></span><a class="headerlink" title="Permalink to this term" href="#shutdown.target">¶</a></dt><dd><p>A special target unit that terminates the services on | |
| 203 | system shutdown.</p><p>Services that shall be terminated on system shutdown | |
| 204 | shall add <code class="varname">Conflicts=</code> dependencies to this | |
| 205 | unit for their service unit, which is implicitly done when | |
| 206 | <code class="varname">DefaultDependencies=yes</code> is set (the | |
| 207 | default).</p></dd><dt id="sigpwr.target"><span class="term"><code class="filename">sigpwr.target</code></span><a class="headerlink" title="Permalink to this term" href="#sigpwr.target">¶</a></dt><dd><p>A special target that is started when systemd receives | |
| 208 | the SIGPWR process signal, which is normally sent by the | |
| 209 | kernel or UPS daemons when power fails.</p></dd><dt id="sleep.target"><span class="term"><code class="filename">sleep.target</code></span><a class="headerlink" title="Permalink to this term" href="#sleep.target">¶</a></dt><dd><p>A special target unit that is pulled in by | |
| 210 | <code class="filename">suspend.target</code>, | |
| 211 | <code class="filename">hibernate.target</code> and | |
| 212 | <code class="filename">hybrid-sleep.target</code> and may be used to | |
| 213 | hook units into the sleep state logic.</p></dd><dt id="sockets.target"><span class="term"><code class="filename">sockets.target</code></span><a class="headerlink" title="Permalink to this term" href="#sockets.target">¶</a></dt><dd><p>A special target unit that sets up all socket | |
| 214 | units.(see | |
| 215 | <a href="systemd.socket.html"><span class="citerefentry"><span class="refentrytitle">systemd.socket</span>(5)</span></a> | |
| 216 | for details) that shall be active after boot.</p><p>Services that can be socket-activated shall add | |
| 217 | <code class="varname">Wants=</code> dependencies to this unit for | |
| 218 | their socket unit during installation. This is best | |
| 219 | configured via a <code class="varname">WantedBy=sockets.target</code> | |
| 220 | in the socket unit's "<code class="literal">[Install]</code>" | |
| 221 | section.</p></dd><dt id="suspend.target"><span class="term"><code class="filename">suspend.target</code></span><a class="headerlink" title="Permalink to this term" href="#suspend.target">¶</a></dt><dd><p>A special target unit for suspending the system. This | |
| 222 | pulls in <code class="filename">sleep.target</code>.</p></dd><dt id="swap.target"><span class="term"><code class="filename">swap.target</code></span><a class="headerlink" title="Permalink to this term" href="#swap.target">¶</a></dt><dd><p>Similar to <code class="filename">local-fs.target</code>, but | |
| 223 | for swap partitions and swap files.</p></dd><dt id="sysinit.target"><span class="term"><code class="filename">sysinit.target</code></span><a class="headerlink" title="Permalink to this term" href="#sysinit.target">¶</a></dt><dd><p>A special target unit covering early boot-up | |
| 224 | scripts.</p></dd><dt id="syslog.socket"><span class="term"><code class="filename">syslog.socket</code></span><a class="headerlink" title="Permalink to this term" href="#syslog.socket">¶</a></dt><dd><p>The socket unit syslog implementations should listen | |
| 225 | on. All userspace log messages will be made available on | |
| 226 | this socket. For more information about syslog integration, | |
| 227 | please consult the <a class="ulink" href="http://www.freedesktop.org/wiki/Software/systemd/syslog" target="_top">Syslog | |
| 228 | Interface</a> document.</p></dd><dt id="system-update.target"><span class="term"><code class="filename">system-update.target</code></span><a class="headerlink" title="Permalink to this term" href="#system-update.target">¶</a></dt><dd><p>A special target unit that is used for off-line system | |
| 229 | updates. | |
| 230 | <a href="systemd-system-update-generator.html"><span class="citerefentry"><span class="refentrytitle">systemd-system-update-generator</span>(8)</span></a> | |
| 231 | will redirect the boot process to this target if | |
| 232 | <code class="filename">/system-update</code> exists. For more | |
| 233 | information see the <a class="ulink" href="http://freedesktop.org/wiki/Software/systemd/SystemUpdates" target="_top">System | |
| 234 | Updates Specification</a>.</p></dd><dt id="timers.target"><span class="term"><code class="filename">timers.target</code></span><a class="headerlink" title="Permalink to this term" href="#timers.target">¶</a></dt><dd><p>A special target unit that sets up all timer units | |
| 235 | (see | |
| 236 | <a href="systemd.timer.html"><span class="citerefentry"><span class="refentrytitle">systemd.timer</span>(5)</span></a> | |
| 237 | for details) that shall be active after boot.</p><p>It is recommended that timer units installed by | |
| 238 | applications get pulled in via <code class="varname">Wants=</code> | |
| 239 | dependencies from this unit. This is best configured via | |
| 240 | <code class="varname">WantedBy=timers.target</code> in the timer | |
| 241 | unit's "<code class="literal">[Install]</code>" section.</p></dd><dt id="umount.target"><span class="term"><code class="filename">umount.target</code></span><a class="headerlink" title="Permalink to this term" href="#umount.target">¶</a></dt><dd><p>A special target unit that umounts all mount and | |
| 242 | automount points on system shutdown.</p><p>Mounts that shall be unmounted on system shutdown | |
| 243 | shall add Conflicts dependencies to this unit for their | |
| 244 | mount unit, which is implicitly done when | |
| 245 | <code class="varname">DefaultDependencies=yes</code> is set (the | |
| 246 | default).</p></dd></dl></div></div><div class="refsect1"><a name="idm140275571332224"></a><h2 id="Special System Units for Devices">Special System Units for Devices<a class="headerlink" title="Permalink to this headline" href="#Special%20System%20Units%20for%20Devices">¶</a></h2><p>Some target units are automatically pulled in as devices of | |
| 247 | certain kinds show up in the system. These may be used to | |
| 248 | automatically activate various services based on the specific type | |
| 249 | of the available hardware.</p><div class="variablelist"><dl class="variablelist"><dt id="bluetooth.target"><span class="term"><code class="filename">bluetooth.target</code></span><a class="headerlink" title="Permalink to this term" href="#bluetooth.target">¶</a></dt><dd><p>This target is started automatically as soon as a | |
| 250 | Bluetooth controller is plugged in or becomes available at | |
| 251 | boot.</p><p>This may be used to pull in Bluetooth management | |
| 252 | daemons dynamically when Bluetooth hardware is found.</p></dd><dt id="printer.target"><span class="term"><code class="filename">printer.target</code></span><a class="headerlink" title="Permalink to this term" href="#printer.target">¶</a></dt><dd><p>This target is started automatically as soon as a | |
| 253 | printer is plugged in or becomes available at boot.</p><p>This may be used to pull in printer management daemons | |
| 254 | dynamically when printer hardware is found.</p></dd><dt id="smartcard.target"><span class="term"><code class="filename">smartcard.target</code></span><a class="headerlink" title="Permalink to this term" href="#smartcard.target">¶</a></dt><dd><p>This target is started automatically as soon as a | |
| 255 | smartcard controller is plugged in or becomes available at | |
| 256 | boot.</p><p>This may be used to pull in smartcard management | |
| 257 | daemons dynamically when smartcard hardware is found.</p></dd><dt id="sound.target"><span class="term"><code class="filename">sound.target</code></span><a class="headerlink" title="Permalink to this term" href="#sound.target">¶</a></dt><dd><p>This target is started automatically as soon as a | |
| 258 | sound card is plugged in or becomes available at | |
| 259 | boot.</p><p>This may be used to pull in audio management daemons | |
| 260 | dynamically when audio hardware is found.</p></dd></dl></div></div><div class="refsect1"><a name="idm140275571320224"></a><h2 id="Special Passive System Units ">Special Passive System Units <a class="headerlink" title="Permalink to this headline" href="#Special%20Passive%20System%20Units%20">¶</a></h2><p>A number of special system targets are defined that can be | |
| 261 | used to properly order boot-up of optional services. These targets | |
| 262 | are generally not part of the initial boot transaction, unless | |
| 263 | they are explicitly pulled in by one of the implementing services. | |
| 264 | Note specifically that these <span class="emphasis"><em>passive</em></span> target | |
| 265 | units are generally not pulled in by the consumer of a service, | |
| 266 | but by the provider of the service. This means: a consuming | |
| 267 | service should order itself after these targets (as appropriate), | |
| 268 | but not pull it in. A providing service should order itself before | |
| 269 | these targets (as appropriate) and pull it in (via a | |
| 270 | <code class="varname">Wants=</code> type dependency).</p><p>Note that these passive units cannot be started manually, | |
| 271 | i.e. "<code class="literal">systemctl start time-sync.target</code>" will fail | |
| 272 | with an error. They can only be pulled in by dependency. This is | |
| 273 | enforced since they exist for ordering purposes only and thus are | |
| 274 | not useful as only unit within a transaction.</p><div class="variablelist"><dl class="variablelist"><dt id="cryptsetup-pre.target"><span class="term"><code class="filename">cryptsetup-pre.target</code></span><a class="headerlink" title="Permalink to this term" href="#cryptsetup-pre.target">¶</a></dt><dd><p>This passive target unit may be pulled in by services | |
| 275 | that want to run before any encrypted block device is set | |
| 276 | up. All encrypted block devices are set up after this target | |
| 277 | has been reached. Since the shutdown order is implicitly the | |
| 278 | reverse start-up order between units, this target is | |
| 279 | particularly useful to ensure that a service is shut down | |
| 280 | only after all encrypted block devices are fully | |
| 281 | stopped.</p></dd><dt id="local-fs-pre.target"><span class="term"><code class="filename">local-fs-pre.target</code></span><a class="headerlink" title="Permalink to this term" href="#local-fs-pre.target">¶</a></dt><dd><p>This target unit is | |
| 282 | automatically ordered before | |
| 283 | all local mount points marked | |
| 284 | with <code class="option">auto</code> | |
| 285 | (see above). It can be used to | |
| 286 | execute certain units before | |
| 287 | all local mounts.</p></dd><dt id="network.target"><span class="term"><code class="filename">network.target</code></span><a class="headerlink" title="Permalink to this term" href="#network.target">¶</a></dt><dd><p>This unit is supposed to indicate when network | |
| 288 | functionality is available, but it is only very weakly | |
| 289 | defined what that is supposed to mean, with one exception: | |
| 290 | at shutdown, a unit that is ordered after | |
| 291 | <code class="filename">network.target</code> will be stopped before | |
| 292 | the network -- to whatever level it might be set up then -- | |
| 293 | is shut down. It is hence useful when writing service files | |
| 294 | that require network access on shutdown, which should order | |
| 295 | themselves after this target, but not pull it in. Also see | |
| 296 | <a class="ulink" href="http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget" target="_top">Running | |
| 297 | Services After the Network is up</a> for more | |
| 298 | information. Also see | |
| 299 | <code class="filename">network-online.target</code> described | |
| 300 | above.</p><p>systemd automatically adds dependencies of type | |
| 301 | <code class="varname">After=</code> for this target unit to all SysV | |
| 302 | init script service units with an LSB header referring to | |
| 303 | the "<code class="literal">$network</code>" facility.</p></dd><dt id="network-pre.target"><span class="term"><code class="filename">network-pre.target</code></span><a class="headerlink" title="Permalink to this term" href="#network-pre.target">¶</a></dt><dd><p>This passive target unit may be pulled in by services | |
| 304 | that want to run before any network is set up, for example | |
| 305 | for the purpose of setting up a firewall. All network | |
| 306 | management software orders itself after this target, but | |
| 307 | does not pull it in.</p></dd><dt id="nss-lookup.target"><span class="term"><code class="filename">nss-lookup.target</code></span><a class="headerlink" title="Permalink to this term" href="#nss-lookup.target">¶</a></dt><dd><p>A target that should be used as synchronization point | |
| 308 | for all host/network name service lookups. Note that this is | |
| 309 | independent of user/group name lookups for which | |
| 310 | <code class="filename">nss-user-lookup.target</code> should be used. | |
| 311 | All services for which the availability of full host/network | |
| 312 | name resolution is essential should be ordered after this | |
| 313 | target, but not pull it in. systemd automatically adds | |
| 314 | dependencies of type <code class="varname">After=</code> for this | |
| 315 | target unit to all SysV init script service units with an | |
| 316 | LSB header referring to the "<code class="literal">$named</code>" | |
| 317 | facility.</p></dd><dt id="nss-user-lookup.target"><span class="term"><code class="filename">nss-user-lookup.target</code></span><a class="headerlink" title="Permalink to this term" href="#nss-user-lookup.target">¶</a></dt><dd><p>A target that should be used as synchronization point | |
| 318 | for all user/group name service lookups. Note that this is | |
| 319 | independent of host/network name lookups for which | |
| 320 | <code class="filename">nss-lookup.target</code> should be used. All | |
| 321 | services for which the availability of the full user/group | |
| 322 | database is essential should be ordered after this target, | |
| 323 | but not pull it in. Note that system users are always | |
| 324 | resolvable, and hence do not require any special ordering | |
| 325 | against this target.</p></dd><dt id="remote-fs-pre.target"><span class="term"><code class="filename">remote-fs-pre.target</code></span><a class="headerlink" title="Permalink to this term" href="#remote-fs-pre.target">¶</a></dt><dd><p>This target unit is automatically ordered before all | |
| 326 | remote mount point units (see above). It can be used to run | |
| 327 | certain units before the remote mounts are established. Note | |
| 328 | that this unit is generally not part of the initial | |
| 329 | transaction, unless the unit that wants to be ordered before | |
| 330 | all remote mounts pulls it in via a | |
| 331 | <code class="varname">Wants=</code> type dependency. If the unit wants | |
| 332 | to be pulled in by the first remote mount showing up, it | |
| 333 | should use <code class="filename">network-online.target</code> (see | |
| 334 | above).</p></dd><dt id="rpcbind.target"><span class="term"><code class="filename">rpcbind.target</code></span><a class="headerlink" title="Permalink to this term" href="#rpcbind.target">¶</a></dt><dd><p>The portmapper/rpcbind pulls in this target and orders | |
| 335 | itself before it, to indicate its availability. systemd | |
| 336 | automatically adds dependencies of type | |
| 337 | <code class="varname">After=</code> for this target unit to all SysV | |
| 338 | init script service units with an LSB header referring to | |
| 339 | the "<code class="literal">$portmap</code>" facility.</p></dd><dt id="time-sync.target"><span class="term"><code class="filename">time-sync.target</code></span><a class="headerlink" title="Permalink to this term" href="#time-sync.target">¶</a></dt><dd><p>Services responsible for synchronizing the system | |
| 340 | clock from a remote source (such as NTP client | |
| 341 | implementations) should pull in this target and order | |
| 342 | themselves before it. All services where correct time is | |
| 343 | essential should be ordered after this unit, but not pull it | |
| 344 | in. systemd automatically adds dependencies of type | |
| 345 | <code class="varname">After=</code> for this target unit to all SysV | |
| 346 | init script service units with an LSB header referring to | |
| 347 | the "<code class="literal">$time</code>" facility. </p></dd></dl></div></div><div class="refsect1"><a name="idm140275571285408"></a><h2 id="Special User Units">Special User Units<a class="headerlink" title="Permalink to this headline" href="#Special%20User%20Units">¶</a></h2><p>When systemd runs as a user instance, the following special | |
| 348 | units are available, which have similar definitions as their | |
| 349 | system counterparts: | |
| 350 | <code class="filename">default.target</code>, | |
| 351 | <code class="filename">shutdown.target</code>, | |
| 352 | <code class="filename">sockets.target</code>, | |
| 353 | <code class="filename">timers.target</code>, | |
| 354 | <code class="filename">paths.target</code>, | |
| 355 | <code class="filename">bluetooth.target</code>, | |
| 356 | <code class="filename">printer.target</code>, | |
| 357 | <code class="filename">smartcard.target</code>, | |
| 358 | <code class="filename">sound.target</code>.</p><p>In addition, the following special unit is understood only | |
| 359 | when systemd runs as service instance:</p><div class="variablelist"><dl class="variablelist"><dt id="exit.target"><span class="term"><code class="filename">exit.target</code></span><a class="headerlink" title="Permalink to this term" href="#exit.target">¶</a></dt><dd><p>A special service unit for shutting down the user | |
| 360 | service manager.</p><p>Applications wanting to terminate the user service | |
| 361 | manager should start this unit. If systemd receives | |
| 362 | <code class="constant">SIGTERM</code> or <code class="constant">SIGINT</code> | |
| 363 | when running as user service daemon, it will start this | |
| 364 | unit.</p><p>Normally, this pulls in | |
| 365 | <code class="filename">shutdown.target</code> which in turn should be | |
| 366 | conflicted by all units that want to be shut down on user | |
| 367 | service manager exit.</p></dd></dl></div></div><div class="refsect1"><a name="idm140275571273040"></a><h2 id="Special Slice Units">Special Slice Units<a class="headerlink" title="Permalink to this headline" href="#Special%20Slice%20Units">¶</a></h2><p>There are four "<code class="literal">.slice</code>" units which form | |
| 368 | the basis of the hierarchy for assignment of resources for | |
| 369 | services, users, and virtual machines or containers.</p><div class="variablelist"><dl class="variablelist"><dt id="-.slice"><span class="term"><code class="filename">-.slice</code></span><a class="headerlink" title="Permalink to this term" href="#-.slice">¶</a></dt><dd><p>The root slice is the root of the hierarchy. It | |
| 370 | usually does not contain units directly, but may be used to | |
| 371 | set defaults for the whole tree.</p></dd><dt id="system.slice"><span class="term"><code class="filename">system.slice</code></span><a class="headerlink" title="Permalink to this term" href="#system.slice">¶</a></dt><dd><p>By default, all services services started by | |
| 372 | <span class="command"><strong>systemd</strong></span> are found in this slice.</p></dd><dt id="user.slice"><span class="term"><code class="filename">user.slice</code></span><a class="headerlink" title="Permalink to this term" href="#user.slice">¶</a></dt><dd><p>By default, all user processes and services started on | |
| 373 | behalf of the user, including the per-user systemd instance | |
| 374 | are found in this slice.</p></dd><dt id="machine.slice"><span class="term"><code class="filename">machine.slice</code></span><a class="headerlink" title="Permalink to this term" href="#machine.slice">¶</a></dt><dd><p>By default, all virtual machines and containers | |
| 375 | registered with <span class="command"><strong>systemd-machined</strong></span> are | |
| 376 | found in this slice. | |
| 377 | </p></dd></dl></div></div><div class="refsect1"><a name="idm140275571261408"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also">¶</a></h2><p> | |
| 378 | <a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>, | |
| 379 | <a href="systemd.unit.html"><span class="citerefentry"><span class="refentrytitle">systemd.unit</span>(5)</span></a>, | |
| 380 | <a href="systemd.service.html"><span class="citerefentry"><span class="refentrytitle">systemd.service</span>(5)</span></a>, | |
| 381 | <a href="systemd.socket.html"><span class="citerefentry"><span class="refentrytitle">systemd.socket</span>(5)</span></a>, | |
| 382 | <a href="systemd.target.html"><span class="citerefentry"><span class="refentrytitle">systemd.target</span>(5)</span></a>, | |
| 383 | <a href="systemd.slice.html"><span class="citerefentry"><span class="refentrytitle">systemd.slice</span>(5)</span></a>, | |
| 384 | <a href="http://man7.org/linux/man-pages/man7/bootup.7.html"><span class="citerefentry"><span class="refentrytitle">bootup</span>(7)</span></a>, | |
| 385 | <a href="systemd-fstab-generator.html"><span class="citerefentry"><span class="refentrytitle">systemd-fstab-generator</span>(8)</span></a> | |
| 386 | </p></div></div></body></html> |