1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
|
<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>systemd.special</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><style>
a.headerlink {
color: #c60f0f;
font-size: 0.8em;
padding: 0 4px 0 4px;
text-decoration: none;
visibility: hidden;
}
a.headerlink:hover {
background-color: #c60f0f;
color: white;
}
h1:hover > a.headerlink, h2:hover > a.headerlink, h3:hover > a.headerlink, dt:hover > a.headerlink {
visibility: visible;
}
</style><a href="index.html">Index </a>·
<a href="systemd.directives.html">Directives </a>·
<a href="../python-systemd/index.html">Python </a>·
<a href="../libudev/index.html">libudev </a>·
<a href="../libudev/index.html">gudev </a><span style="float:right">systemd 215</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>,
<code class="filename">bluetooth.target</code>,
<code class="filename">ctrl-alt-del.target</code>,
<code class="filename">cryptsetup.target</code>,
<code class="filename">cryptsetup-pre.target</code>,
<code class="filename">dbus.service</code>,
<code class="filename">dbus.socket</code>,
<code class="filename">default.target</code>,
<code class="filename">display-manager.service</code>,
<code class="filename">emergency.target</code>,
<code class="filename">exit.target</code>,
<code class="filename">final.target</code>,
<code class="filename">getty.target</code>,
<code class="filename">graphical.target</code>,
<code class="filename">halt.target</code>,
<code class="filename">hibernate.target</code>,
<code class="filename">hybrid-sleep.target</code>,
<code class="filename">initrd-fs.target</code>,
<code class="filename">kbrequest.target</code>,
<code class="filename">kexec.target</code>,
<code class="filename">local-fs.target</code>,
<code class="filename">local-fs-pre.target</code>,
<code class="filename">multi-user.target</code>,
<code class="filename">network.target</code>,
<code class="filename">network-online.target</code>,
<code class="filename">network-pre.target</code>,
<code class="filename">nss-lookup.target</code>,
<code class="filename">nss-user-lookup.target</code>,
<code class="filename">paths.target</code>,
<code class="filename">poweroff.target</code>,
<code class="filename">printer.target</code>,
<code class="filename">reboot.target</code>,
<code class="filename">remote-fs.target</code>,
<code class="filename">remote-fs-pre.target</code>,
<code class="filename">rescue.target</code>,
<code class="filename">initrd-root-fs.target</code>,
<code class="filename">rpcbind.target</code>,
<code class="filename">runlevel2.target</code>,
<code class="filename">runlevel3.target</code>,
<code class="filename">runlevel4.target</code>,
<code class="filename">runlevel5.target</code>,
<code class="filename">shutdown.target</code>,
<code class="filename">sigpwr.target</code>,
<code class="filename">sleep.target</code>,
<code class="filename">smartcard.target</code>,
<code class="filename">sockets.target</code>,
<code class="filename">sound.target</code>,
<code class="filename">suspend.target</code>,
<code class="filename">swap.target</code>,
<code class="filename">sysinit.target</code>,
<code class="filename">syslog.socket</code>,
<code class="filename">system-update.target</code>,
<code class="filename">time-sync.target</code>,
<code class="filename">timers.target</code>,
<code class="filename">umount.target</code>,
<code class="filename">-.slice</code>,
<code class="filename">system.slice</code>,
<code class="filename">user.slice</code>,
<code class="filename">machine.slice</code></p></div><div class="refsect1"><a name="idm214177962192"></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 special internal semantics and
cannot be renamed.</p></div><div class="refsect1"><a name="idm214177960848"></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
<code class="varname">Requires=</code>
and <code class="varname">After=</code>
for this target unit to all
services (except for those
with
<code class="varname">DefaultDependencies=no</code>).</p><p>Usually this should
pull-in all mount points, swap
devices, sockets, timers, and
path units and other basic
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 pressed on
the console. Usually this
should be aliased (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
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
this service is fully started
up systemd will connect to it
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
units with
<code class="varname">Type=dbus</code>
automatically gain a
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 this
should be aliased (symlinked)
to
<code class="filename">multi-user.target</code>
or
<code class="filename">graphical.target</code>.</p><p>The default unit systemd
starts at bootup can be
overridden with the
<code class="varname">systemd.unit=</code>
kernel 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 aliased (symlinked) to
<code class="filename">gdm.service</code>
or a 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 on the main
console. This unit is supposed
to be used with the kernel
command line option
<code class="varname">systemd.unit=</code>
and has otherwise little use.
</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 logic and may be used
to pull in late services after
all normal services are
already terminated and all
mounts unmounted.
</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
configured local TTY
<code class="filename">getty</code>
instances.
</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 screen. This pulls in
<code class="filename">multi-user.target</code>.</p><p>Units that are needed
for graphical logins shall add
<code class="varname">Wants=</code>
dependencies for their unit to
this unit (or
<code class="filename">multi-user.target</code>)
during installation. This is
best configured via
<code class="varname">WantedBy=graphical.target</code>
in the unit's
"<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 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 the
system at the same time. This pulls in
<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
the system. Note that this
target is distinct from
<code class="filename">poweroff.target</code>
in that it generally really
just halts the system rather
than powering it down.</p><p>Applications wanting to
halt the system should start
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>
automatically adds
dependencies of type
<code class="varname">Before=</code> to
<code class="filename">sysroot-usr.mount</code>
and all mount points found in
<code class="filename">/etc/fstab</code>
that have
<code class="option">x-initrd.mount</code>
and not have <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
pressed on the console. This
is a good candidate to be
aliased (symlinked) to
<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 the system via kexec.</p><p>Applications wanting to
reboot the system with kexec 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>
automatically adds
dependencies of type
<code class="varname">Before=</code> to
all mount units that refer to
local mount points for this
target unit. In addition, it
adds dependencies of type
<code class="varname">Wants=</code> to
this target unit for those
mounts listed in
<code class="filename">/etc/fstab</code>
that have the
<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
system (non-graphical). This
is pulled in by
<code class="filename">graphical.target</code>.</p><p>Units that are needed
for a multi-user system shall
add <code class="varname">Wants=</code>
dependencies for their unit to
this unit during
installation. This is best
configured via
<code class="varname">WantedBy=multi-user.target</code>
in the unit's
"<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
connection should pull in
<code class="filename">network-online.target</code>
(via a
<code class="varname">Wants=</code> 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.</p><p>Note the distinction
between this unit and
<code class="filename">network.target</code>. 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,
<code class="filename">network.target</code>
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,
<code class="filename">network.target</code>
is part of the boot of most
systems, while
<code class="filename">network-online.target</code>
is not, except when at least
one unit requires it. Also see
<a class="ulink" href="http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget" target="_top">Running
Services After the Network is
up</a> for more
information.</p><p>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.</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
<a href="systemd.path.html"><span class="citerefentry"><span class="refentrytitle">systemd.path</span>(5)</span></a>
for details) that shall be
active after boot.</p><p>It is recommended that
path units installed by
applications get pulled in via
<code class="varname">Wants=</code>
dependencies from this
unit. This is best configured
via a
<code class="varname">WantedBy=paths.target</code>
in the path unit's
"<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 off the system.</p><p>Applications wanting to
power off the system should start
this unit.</p><p><code class="filename">runlevel0.target</code>
is an alias for 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 the system.</p><p>Applications wanting to
reboot the system should start
this unit.</p><p><code class="filename">runlevel6.target</code>
is an alias for 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 for remote mount
points.</p><p>systemd automatically
adds dependencies of type
<code class="varname">After=</code> for
this target unit to all SysV
init script service units with
an LSB header referring to 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
and a rescue shell.</p><p><code class="filename">runlevel1.target</code>
is an alias for 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>
automatically adds
dependencies of type
<code class="varname">Before=</code> to
the
<code class="filename">sysroot.mount</code>
unit, which is generated from
the kernel command line.
</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
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)
<code class="filename">multi-user.target</code>
(for runlevel 2) or
<code class="filename">graphical.target</code>
(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 system shutdown.</p><p>Services that shall be
terminated on system shutdown
shall add <code class="varname">Conflicts=</code>
dependencies to this unit for
their service unit, which is
implicitly done when
<code class="varname">DefaultDependencies=yes</code>
is set (the 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
the SIGPWR process signal,
which is normally sent by the
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
<code class="filename">suspend.target</code>,
<code class="filename">hibernate.target</code>
and
<code class="filename">hybrid-sleep.target</code>
and may be used to 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
units.(see
<a href="systemd.socket.html"><span class="citerefentry"><span class="refentrytitle">systemd.socket</span>(5)</span></a>
for details) that shall be
active after boot.</p><p>Services that can be
socket-activated shall add
<code class="varname">Wants=</code>
dependencies to this unit for
their socket unit during
installation. This is best
configured via a
<code class="varname">WantedBy=sockets.target</code>
in the socket unit's
"<code class="literal">[Install]</code>"
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 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 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 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 on. All userspace log
messages will be made
available on this socket. For
more information about syslog
integration, please consult
the <a class="ulink" href="http://www.freedesktop.org/wiki/Software/systemd/syslog" target="_top">Syslog
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 updates.
<a href="systemd-system-update-generator.html"><span class="citerefentry"><span class="refentrytitle">systemd-system-update-generator</span>(8)</span></a>
will redirect the boot process
to this target if
<code class="filename">/system-update</code>
exists. For more information
see the <a class="ulink" href="http://freedesktop.org/wiki/Software/systemd/SystemUpdates" target="_top">System
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 (see
<a href="systemd.timer.html"><span class="citerefentry"><span class="refentrytitle">systemd.timer</span>(5)</span></a>
for details) that shall be
active after boot.</p><p>It is recommended that
timer units installed by
applications get pulled in via
<code class="varname">Wants=</code>
dependencies from this
unit. This is best configured
via
<code class="varname">WantedBy=timers.target</code>
in the timer 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
automount points on system
shutdown.</p><p>Mounts that shall be
unmounted on system shutdown
shall add Conflicts
dependencies to this unit for
their mount unit, which is
implicitly done when
<code class="varname">DefaultDependencies=yes</code>
is set (the default).</p></dd></dl></div></div><div class="refsect1"><a name="idm214172840096"></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 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.</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
Bluetooth controller is
plugged in or becomes
available at boot.</p><p>This may be used to pull
in Bluetooth management
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
printer is plugged in or
becomes available at
boot.</p><p>This may be used to pull
in printer management
daemons 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
smartcard controller is
plugged in or becomes
available at boot.</p><p>This may be used to pull
in smartcard management
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
sound card is plugged in or
becomes available at
boot.</p><p>This may be used to pull
in audio management daemons
dynamically when audio
hardware is found.</p></dd></dl></div></div><div class="refsect1"><a name="idm214172826944"></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 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 <span class="emphasis"><em>passive</em></span>
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 <code class="varname">Wants=</code> type
dependency).</p><p>Note that these passive units cannot be started
manually, i.e. "<code class="literal">systemctl start
time-sync.target</code>" 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.</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
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.</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
automatically ordered before
all local mount points marked
with <code class="option">auto</code>
(see above). It can be used to
execute certain units before
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
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
<code class="filename">network.target</code>
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
<a class="ulink" href="http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget" target="_top">Running
Services After the Network is
up</a> for more
information. Also see
<code class="filename">network-online.target</code>
described above.</p><p>systemd automatically
adds dependencies of type
<code class="varname">After=</code> for
this target unit to all SysV
init script service units with
an LSB header referring to 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
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.</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
for all host/network name
service lookups. Note that
this is independent of
user/group name lookups for
which
<code class="filename">nss-user-lookup.target</code>
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
<code class="varname">After=</code> for
this target unit to all SysV
init script service units with
an LSB header referring to the
"<code class="literal">$named</code>"
facility.</p></dd><dt id="nss-user-lookup.target"><span class="term"><code class="filename">nss-user-lookup.target</code></span><a class="headerlink" title="Permalink to this term" href="#nss-user-lookup.target">¶</a></dt><dd><p>A target that should be
used as synchronization point
for all user/group name
service lookups. Note that
this is independent of
host/network name lookups for
which
<code class="filename">nss-lookup.target</code>
should be used. All services
for which the availability of
the full user/group database is
essential should be ordered
after this target, but not
pull it in. Note that system
users are always resolvable,
and hence do not require any
special ordering against this
target.</p></dd><dt id="remote-fs-pre.target"><span class="term"><code class="filename">remote-fs-pre.target</code></span><a class="headerlink" title="Permalink to this term" href="#remote-fs-pre.target">¶</a></dt><dd><p>This target unit is
automatically ordered before
all remote mount point units
(see above). It can be used to
run certain units before the
remote mounts are
established. Note that this
unit is generally not part of
the initial transaction,
unless the unit that wants to
be ordered before all remote
mounts pulls it in via a
<code class="varname">Wants=</code> type
dependency. If the unit wants
to be pulled in by the first
remote mount showing up, it
should use
<code class="filename">network-online.target</code>
(see above).</p></dd><dt id="rpcbind.target"><span class="term"><code class="filename">rpcbind.target</code></span><a class="headerlink" title="Permalink to this term" href="#rpcbind.target">¶</a></dt><dd><p>The portmapper/rpcbind
pulls in this target and
orders itself before it, to
indicate its
availability. systemd
automatically adds
dependencies of type
<code class="varname">After=</code> for
this target unit to all SysV
init script service units with
an LSB header referring to the
"<code class="literal">$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 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
<code class="varname">After=</code> for
this target unit to all SysV
init script service units with
an LSB header referring to the
"<code class="literal">$time</code>"
facility. </p></dd></dl></div></div><div class="refsect1"><a name="idm214172785472"></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 units are available, which have
similar definitions as their system counterparts:
<code class="filename">default.target</code>,
<code class="filename">shutdown.target</code>,
<code class="filename">sockets.target</code>,
<code class="filename">timers.target</code>,
<code class="filename">paths.target</code>,
<code class="filename">bluetooth.target</code>,
<code class="filename">printer.target</code>,
<code class="filename">smartcard.target</code>,
<code class="filename">sound.target</code>.</p><p>In addition, the following special unit is
understood only 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 service manager.</p><p>Applications wanting to
terminate the user service
manager should start this
unit. If systemd receives
<code class="constant">SIGTERM</code> or <code class="constant">SIGINT</code> when running
as user service daemon, it will
start this unit.</p><p>Normally, this pulls in
<code class="filename">shutdown.target</code>
which in turn should be
conflicted by all units that
want to be shut down on
user service manager exit.</p></dd></dl></div></div><div class="refsect1"><a name="idm214172772576"></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 the basis of the hierarchy for assignment
of resources for 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
usually does not contain units
directly, but may be used to
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
<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 behalf of the user,
including the per-user systemd
instance 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
registered with
<span class="command"><strong>systemd-machined</strong></span>
are found in this slice.
</p></dd></dl></div></div><div class="refsect1"><a name="idm214172760096"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also">¶</a></h2><p>
<a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
<a href="systemd.unit.html"><span class="citerefentry"><span class="refentrytitle">systemd.unit</span>(5)</span></a>,
<a href="systemd.service.html"><span class="citerefentry"><span class="refentrytitle">systemd.service</span>(5)</span></a>,
<a href="systemd.socket.html"><span class="citerefentry"><span class="refentrytitle">systemd.socket</span>(5)</span></a>,
<a href="systemd.target.html"><span class="citerefentry"><span class="refentrytitle">systemd.target</span>(5)</span></a>,
<a href="systemd.slice.html"><span class="citerefentry"><span class="refentrytitle">systemd.slice</span>(5)</span></a>,
<a href="bootup.html"><span class="citerefentry"><span class="refentrytitle">bootup</span>(7)</span></a>,
<a href="systemd-fstab-generator.html"><span class="citerefentry"><span class="refentrytitle">systemd-fstab-generator</span>(8)</span></a>
</p></div></div></body></html>
|
