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
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
|
<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="systemd.special">
<refentryinfo>
<title>systemd.special</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>systemd.special</refentrytitle>
<manvolnum>7</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd.special</refname>
<refpurpose>Special systemd units</refpurpose>
</refnamediv>
<refsynopsisdiv>
<para><filename>basic.target</filename>,
<filename>bluetooth.target</filename>,
<filename>ctrl-alt-del.target</filename>,
<filename>cryptsetup.target</filename>,
<filename>dbus.service</filename>,
<filename>dbus.socket</filename>,
<filename>default.target</filename>,
<filename>display-manager.service</filename>,
<filename>emergency.target</filename>,
<filename>exit.target</filename>,
<filename>final.target</filename>,
<filename>getty.target</filename>,
<filename>graphical.target</filename>,
<filename>hibernate.target</filename>,
<filename>http-daemon.target</filename>,
<filename>halt.target</filename>,
<filename>kbrequest.target</filename>,
<filename>kexec.target</filename>,
<filename>local-fs.target</filename>,
<filename>local-fs-pre.target</filename>,
<filename>mail-transfer-agent.target</filename>,
<filename>multi-user.target</filename>,
<filename>network.target</filename>,
<filename>nss-lookup.target</filename>,
<filename>nss-user-lookup.target</filename>,
<filename>poweroff.target</filename>,
<filename>printer.target</filename>,
<filename>reboot.target</filename>,
<filename>remote-fs.target</filename>,
<filename>remote-fs-pre.target</filename>,
<filename>rescue.target</filename>,
<filename>rpcbind.target</filename>,
<filename>runlevel2.target</filename>,
<filename>runlevel3.target</filename>,
<filename>runlevel4.target</filename>,
<filename>runlevel5.target</filename>,
<filename>shutdown.target</filename>,
<filename>sigpwr.target</filename>,
<filename>sleep.target</filename>,
<filename>smartcard.target</filename>,
<filename>sockets.target</filename>,
<filename>sound.target</filename>,
<filename>suspend.target</filename>,
<filename>swap.target</filename>,
<filename>sysinit.target</filename>,
<filename>syslog.service</filename>,
<filename>syslog.socket</filename>,
<filename>syslog.target</filename>,
<filename>time-sync.target</filename>,
<filename>umount.target</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>A few units are treated specially by
systemd. They have special internal semantics and
cannot be renamed.</para>
</refsect1>
<refsect1>
<title>Special System Units</title>
<variablelist>
<varlistentry>
<term><filename>basic.target</filename></term>
<listitem>
<para>A special target unit
covering early boot-up.</para>
<para>systemd automatically
adds dependencies of the types
Requires and After for this
target unit to all SysV
service units configured for
runlevel 1 to 5.</para>
<para>Usually this should pull-in
all sockets, mount points,
swap devices and other basic
initialization necessary for
the general purpose
daemons. Most normal daemons
should have dependencies of
type After and Requires on
this unit.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>bluetooth.target</filename></term>
<listitem>
<para>This target is started
automatically as soon as a
bluetooth controller is
plugged in or becomes
available at boot.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>ctrl-alt-del.target</filename></term>
<listitem>
<para>systemd starts this
target whenever
Control+Alt+Del is pressed on
the console. Usually this
should be aliased (symlinked)
to
<filename>reboot.target</filename>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>cryptsetup.target</filename></term>
<listitem>
<para>A target that pulls in
setup services for all
encrypted block
devices.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>dbus.service</filename></term>
<listitem>
<para>A special unit for the
D-Bus system bus. As soon as
this service is fully started
up systemd will connect to it
and register its
service.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>dbus.socket</filename></term>
<listitem>
<para>A special unit for the
D-Bus system bus socket. All
units with
<literal>Type=dbus</literal>
automatically gain a
dependency on this
unit.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>default.target</filename></term>
<listitem>
<para>The default unit systemd
starts at bootup. Usually this
should be aliased (symlinked)
to
<filename>multi-user.target</filename>
or
<filename>graphical.target</filename>.</para>
<para>The default unit systemd
starts at bootup can be
overridden with the
<varname>systemd.unit=</varname>
kernel command line option.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>display-manager.service</filename></term>
<listitem>
<para>The display manager
service. Usually this should
be aliased (symlinked) to
<filename>gdm.service</filename>
or a similar display manager
service.</para>
<para>systemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with a LSB header
referring to the
<literal>$x-display-manager</literal>
facility, for compatibility
with Debian.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>emergency.target</filename></term>
<listitem>
<para>A special target unit
that starts an emergency
shell on the main
console. This unit is supposed
to be used with the kernel
command line option
<varname>systemd.unit=</varname>
and has otherwise little use.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>final.target</filename></term>
<listitem>
<para>A special target unit
that is used during the
shutdown logic and may be used
to pull in late services after
all normal services are
already terminated and all
mounts unmounted.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>getty.target</filename></term>
<listitem>
<para>A special target unit
that pulls in all local TTY
<filename>getty</filename> instances.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>graphical.target</filename></term>
<listitem>
<para>A special target unit
for setting up a graphical
login screen. This pulls in
<filename>multi-user.target</filename>.</para>
<para>Units that are needed
for graphical login shall add
Wants dependencies for their
unit to this unit (or
<filename>multi-user.target</filename>)
during installation.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>hibernate.target</filename></term>
<listitem>
<para>A special target unit
for hibernating the
system. This pulls in
<filename>sleep.target</filename>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>http-daemon.target</filename></term>
<listitem>
<para>A target for pulling in
an HTTP server if there is
any.</para>
<para>systemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with a LSB header
referring to the
<literal>$httpd</literal>
facility.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>halt.target</filename></term>
<listitem>
<para>A special target unit
for shutting down and halting the system.</para>
<para>Applications wanting to
halt the system should start
this unit.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>kbrequest.target</filename></term>
<listitem>
<para>systemd starts this
target whenever Alt+ArrowUp is
pressed on the console. This
is a good candidate to be
aliased (symlinked) to
<filename>rescue.target</filename>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>kexec.target</filename></term>
<listitem>
<para>A special target unit
for shutting down and rebooting the system via kexec.</para>
<para>Applications wanting to
reboot the system with kexec should start
this unit.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>local-fs.target</filename></term>
<listitem>
<para>systemd automatically
adds dependencies of type
After to all mount units that
refer to local mount points
for this target unit. In
addition, systemd adds
dependencies of type Wants to
this target unit for those
mounts listed in
<filename>/etc/fstab</filename>
that have the
<option>auto</option> and
<option>comment=systemd.mount</option>
mount options set.</para>
<para>systemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with an LSB header
referring to the
<literal>$local_fs</literal>
facility.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>local-fs-pre.target</filename></term>
<listitem>
<para>This target unit is
automatically ordered before
all local mount points marked
with <option>auto</option>
(see above). It can be used to
execute certain units before
all local mounts.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>mail-transfer-agent.target</filename></term>
<listitem>
<para>The mail transfer agent
(MTA) service. Usually this
should pull-in all units
necessary for
sending/receiving mails on the
local host.</para>
<para>systemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with an LSB header
referring to the
<literal>$mail-transfer-agent</literal>
or
<literal>$mail-transport-agent</literal>
facilities, for compatibility
with Debian.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>multi-user.target</filename></term>
<listitem>
<para>A special target unit
for setting up a multi-user
system (non-graphical). This
is pulled in by
<filename>graphical.target</filename>.</para>
<para>Units that are needed
for a multi-user system shall
add Wants dependencies to
this unit for their unit during
installation.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>network.target</filename></term>
<listitem>
<para>systemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with an LSB header
referring to the
<literal>$network</literal>
facility.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>nss-lookup.target</filename></term>
<listitem>
<para>A target that should be
used as synchronization point
for all host/network name
service lookups. Note that
this is independent of
user/group name lookups for
which
<filename>nss-user-lookup.target</filename>
should be used. systemd
automatically adds
dependencies of type After for
this target unit to all SysV
init script service units with
an LSB header referring to the
<literal>$named</literal>
facility.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>nss-user-lookup.target</filename></term>
<listitem>
<para>A target that should be
used as synchronization point
for all user/group name
service lookups. Note that
this is independent of
host/network name lookups for
which
<filename>nss-lookup.target</filename>
should be used. </para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>poweroff.target</filename></term>
<listitem>
<para>A special target unit
for shutting down and powering off the system.</para>
<para>Applications wanting to
power off the system should start
this unit.</para>
<para><filename>runlevel0.target</filename>
is an alias for this target
unit, for compatibility with SysV.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>printer.target</filename></term>
<listitem>
<para>This target is started
automatically as soon as a
printer is plugged in or
becomes available at
boot.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>reboot.target</filename></term>
<listitem>
<para>A special target unit
for shutting down and rebooting the system.</para>
<para>Applications wanting to
reboot the system should start
this unit.</para>
<para><filename>runlevel6.target</filename>
is an alias for this target
unit, for compatibility with SysV.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>remote-fs.target</filename></term>
<listitem>
<para>Similar to
<filename>local-fs.target</filename>,
but for remote mount
points.</para>
<para>systemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with an LSB header
referring to the
<literal>$remote_fs</literal>
facility.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>remote-fs-pre.target</filename></term>
<listitem>
<para>This target unit is
automatically ordered before
all remote mount points marked
with <option>auto</option>
(see above). It can be used to
execute certain units before
all remote mounts.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>rescue.target</filename></term>
<listitem>
<para>A special target unit
for setting up the base system
and a rescue shell.</para>
<para><filename>runlevel1.target</filename>
is an alias for this target
unit, for compatibility with SysV.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>rpcbind.target</filename></term>
<listitem>
<para>systemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with an LSB header
referring to the
<literal>$rpcbind</literal>
facility.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>runlevel2.target</filename></term>
<listitem>
<para>This is a target that is
called whenever the SysV
compatibility code asks for
runlevel 2. It is a good idea
to make this an alias for
(i.e. symlink to)
<filename>multi-user.target</filename>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>runlevel3.target</filename></term>
<listitem>
<para>This is a target that is
called whenever the SysV
compatibility code asks for
runlevel 3. It is a good idea
to make this an alias for
(i.e. symlink to)
<filename>multi-user.target</filename>
or
<filename>graphical.target</filename>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>runlevel4.target</filename></term>
<listitem>
<para>This is a target that is
called whenever the SysV
compatibility code asks for
runlevel 4. It is a good idea
to make this an alias for
(i.e. symlink to)
<filename>multi-user.target</filename>
or
<filename>graphical.target</filename>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>runlevel5.target</filename></term>
<listitem>
<para>This is a target that is
called whenever the SysV
compatibility code asks for
runlevel 5. It is a good idea
to make this an alias for
(i.e. symlink to)
<filename>multi-user.target</filename>
or
<filename>graphical.target</filename>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>shutdown.target</filename></term>
<listitem>
<para>A special target unit
that terminates the services
on system shutdown.</para>
<para>Services that shall be
terminated on system shutdown
shall add Conflicts
dependencies to this unit for
their service unit, which is
implicitly done when
<varname>DefaultDependencies=yes</varname>
is set (the default).</para>
<para>systemd automatically
adds dependencies of type
Conflicts to this target unit
for all SysV init script
service units that shall be
terminated in SysV runlevels 0
or 6.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>sigpwr.target</filename></term>
<listitem>
<para>A special target that is
started when systemd receives
the SIGPWR process signal,
which is normally sent by the
kernel or UPS daemons when
power fails.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>sleep.target</filename></term>
<listitem>
<para>A special target unit
that is pulled in by
<filename>suspend.target</filename>
and
<filename>hibernate.target</filename>
and may be used to hook units
into the sleep state
logic.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>smartcard.target</filename></term>
<listitem>
<para>This target is started
automatically as soon as a
smartcard controller is
plugged in or becomes
available at boot.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>sockets.target</filename></term>
<listitem>
<para>A special target unit
that sets up all service
sockets.</para>
<para>Services that can be
socket-activated shall add
Wants dependencies to this
unit for their socket unit
during installation.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>sound.target</filename></term>
<listitem>
<para>This target is started
automatically as soon as a
sound card is plugged in or
becomes available at
boot.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>suspend.target</filename></term>
<listitem>
<para>A special target unit
for suspending the
system. This pulls in
<filename>sleep.target</filename>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>swap.target</filename></term>
<listitem>
<para>Similar to
<filename>local-fs.target</filename>, but for swap
partitions and swap
files.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>sysinit.target</filename></term>
<listitem>
<para>A special target unit
covering early boot-up scripts.</para>
<para>systemd automatically
adds dependencies of the types
Wants and After for all
SysV service units configured
for runlevels that are not 0
to 6 to this target unit.
This covers the special
boot-up runlevels some
distributions have, such as S
or b.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>syslog.service</filename></term>
<listitem>
<para>The syslog service if
any. Implementations should
create a symlink from the
actual syslog implementation
to this generic name for
activating it.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>syslog.socket</filename></term>
<listitem>
<para>The socket unit where
syslog implementations should
listen on. All userspace log
messages will be made
available on this
socket.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>syslog.target</filename></term>
<listitem>
<para>systemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with an LSB header
referring to the
<literal>$syslog</literal>
facility.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>time-sync.target</filename></term>
<listitem>
<para>systemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with an LSB header
referring to the
<literal>$time</literal>
facility.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>umount.target</filename></term>
<listitem>
<para>A special target unit
that umounts all mount and
automount points on system
shutdown.</para>
<para>Mounts that shall be
unmounted on system shutdown
shall add Conflicts
dependencies to this unit for
their mount unit, which is
implicitly done when
<varname>DefaultDependencies=yes</varname>
is set (the default).</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Special User Units</title>
<para>When systemd runs as a user instance, the
following special units are available, which have
similar definitions as their system counterparts:
<filename>default.target</filename>,
<filename>shutdown.target</filename>,
<filename>sockets.target</filename></para>
<para>In addition the following special unit is
understood only when systemd runs as service instance:</para>
<variablelist>
<varlistentry>
<term><filename>exit.target</filename></term>
<listitem>
<para>A special service unit
for shutting down the
user service manager.</para>
<para>Applications wanting to
terminate the user service
manager should start this
unit. If systemd receives
SIGTERM or SIGINT when running
as user service daemon it will
start this unit.</para>
<para>Normally, this pulls in
<filename>shutdown.target</filename>
which in turn should be
conflicted by all units that
want to be shut down on
user service manager exit.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
|