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6300502b | 1 | <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> |
663996b3 | 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" |
e735f4d4 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
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4 | |
5 | <!-- | |
52ad194e MB |
6 | SPDX-License-Identifier: LGPL-2.1+ |
7 | ||
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8 | This file is part of systemd. |
9 | ||
10 | Copyright 2010 Lennart Poettering | |
11 | ||
12 | systemd is free software; you can redistribute it and/or modify it | |
13 | under the terms of the GNU Lesser General Public License as published by | |
14 | the Free Software Foundation; either version 2.1 of the License, or | |
15 | (at your option) any later version. | |
16 | ||
17 | systemd is distributed in the hope that it will be useful, but | |
18 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
20 | Lesser General Public License for more details. | |
21 | ||
22 | You should have received a copy of the GNU Lesser General Public License | |
23 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
24 | --> | |
25 | ||
60f067b4 | 26 | <refentry id="systemd" |
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27 | xmlns:xi="http://www.w3.org/2001/XInclude"> |
28 | ||
29 | <refentryinfo> | |
30 | <title>systemd</title> | |
31 | <productname>systemd</productname> | |
32 | ||
33 | <authorgroup> | |
34 | <author> | |
35 | <contrib>Developer</contrib> | |
36 | <firstname>Lennart</firstname> | |
37 | <surname>Poettering</surname> | |
38 | <email>lennart@poettering.net</email> | |
39 | </author> | |
40 | </authorgroup> | |
41 | </refentryinfo> | |
42 | ||
43 | <refmeta> | |
44 | <refentrytitle>systemd</refentrytitle> | |
45 | <manvolnum>1</manvolnum> | |
46 | </refmeta> | |
47 | ||
48 | <refnamediv> | |
49 | <refname>systemd</refname> | |
50 | <refname>init</refname> | |
51 | <refpurpose>systemd system and service manager</refpurpose> | |
52 | </refnamediv> | |
53 | ||
54 | <refsynopsisdiv> | |
55 | <cmdsynopsis> | |
52ad194e | 56 | <command>/usr/lib/systemd/systemd</command> |
2897b343 | 57 | <arg choice="opt" rep="repeat">OPTIONS</arg> |
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58 | </cmdsynopsis> |
59 | <cmdsynopsis> | |
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60 | <command>init</command> |
61 | <arg choice="opt" rep="repeat">OPTIONS</arg> | |
62 | <arg choice="req">COMMAND</arg> | |
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63 | </cmdsynopsis> |
64 | </refsynopsisdiv> | |
65 | ||
66 | <refsect1> | |
67 | <title>Description</title> | |
68 | ||
69 | <para>systemd is a system and service manager for Linux operating | |
70 | systems. When run as first process on boot (as PID 1), it acts as | |
71 | init system that brings up and maintains userspace | |
72 | services.</para> | |
73 | ||
74 | <para>For compatibility with SysV, if systemd is called as | |
75 | <command>init</command> and a PID that is not 1, it will execute | |
76 | <command>telinit</command> and pass all command line arguments | |
77 | unmodified. That means <command>init</command> and | |
78 | <command>telinit</command> are mostly equivalent when invoked from | |
79 | normal login sessions. See | |
80 | <citerefentry><refentrytitle>telinit</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
81 | for more information.</para> | |
82 | ||
83 | <para>When run as a system instance, systemd interprets the | |
84 | configuration file <filename>system.conf</filename> and the files | |
85 | in <filename>system.conf.d</filename> directories; when run as a | |
86 | user instance, systemd interprets the configuration file | |
87 | <filename>user.conf</filename> and the files in | |
88 | <filename>user.conf.d</filename> directories. See | |
89 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
90 | for more information.</para> | |
91 | </refsect1> | |
92 | ||
93 | <refsect1> | |
94 | <title>Options</title> | |
95 | ||
96 | <para>The following options are understood:</para> | |
97 | ||
98 | <variablelist> | |
99 | <varlistentry> | |
100 | <term><option>--test</option></term> | |
101 | ||
102 | <listitem><para>Determine startup sequence, dump it and exit. | |
103 | This is an option useful for debugging only.</para></listitem> | |
104 | </varlistentry> | |
105 | <varlistentry> | |
106 | <term><option>--dump-configuration-items</option></term> | |
107 | ||
108 | <listitem><para>Dump understood unit configuration items. This | |
109 | outputs a terse but complete list of configuration items | |
110 | understood in unit definition files.</para></listitem> | |
111 | </varlistentry> | |
112 | <varlistentry> | |
113 | <term><option>--unit=</option></term> | |
114 | ||
115 | <listitem><para>Set default unit to activate on startup. If | |
116 | not specified, defaults to | |
117 | <filename>default.target</filename>.</para></listitem> | |
118 | </varlistentry> | |
119 | <varlistentry> | |
120 | <term><option>--system</option></term> | |
121 | <term><option>--user</option></term> | |
122 | ||
123 | <listitem><para>For <option>--system</option>, tell systemd to | |
124 | run a system instance, even if the process ID is not 1, i.e. | |
125 | systemd is not run as init process. <option>--user</option> | |
126 | does the opposite, running a user instance even if the process | |
db2df898 | 127 | ID is 1. Normally, it should not be necessary to pass these |
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128 | options, as systemd automatically detects the mode it is |
129 | started in. These options are hence of little use except for | |
130 | debugging. Note that it is not supported booting and | |
131 | maintaining a full system with systemd running in | |
132 | <option>--system</option> mode, but PID not 1. In practice, | |
133 | passing <option>--system</option> explicitly is only useful in | |
134 | conjunction with <option>--test</option>.</para></listitem> | |
135 | </varlistentry> | |
136 | <varlistentry> | |
137 | <term><option>--dump-core</option></term> | |
138 | ||
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139 | <listitem><para>Enable core dumping on crash. This switch has |
140 | no effect when running as user instance. This setting may also | |
141 | be enabled during boot on the kernel command line via the | |
142 | <varname>systemd.dump_core=</varname> option, see | |
143 | below.</para></listitem> | |
e735f4d4 | 144 | </varlistentry> |
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145 | |
146 | <varlistentry> | |
147 | <term><option>--crash-vt=</option><replaceable>VT</replaceable></term> | |
148 | ||
149 | <listitem><para>Switch to a specific virtual console (VT) on | |
db2df898 | 150 | crash. Takes a positive integer in the range 1–63, or a |
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151 | boolean argument. If an integer is passed, selects which VT to |
152 | switch to. If <constant>yes</constant>, the VT kernel messages | |
153 | are written to is selected. If <constant>no</constant>, no VT | |
154 | switch is attempted. This switch has no effect when running as | |
155 | user instance. This setting may also be enabled during boot, | |
156 | on the kernel command line via the | |
157 | <varname>systemd.crash_vt=</varname> option, see | |
2897b343 | 158 | <!-- FIXME: there is no crash_vt command line option? --> |
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159 | below.</para></listitem> |
160 | </varlistentry> | |
161 | ||
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162 | <varlistentry> |
163 | <term><option>--crash-shell</option></term> | |
164 | ||
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165 | <listitem><para>Run a shell on crash. This switch has no |
166 | effect when running as user instance. This setting may also be | |
167 | enabled during boot, on the kernel command line via the | |
168 | <varname>systemd.crash_shell=</varname> option, see | |
169 | below.</para></listitem> | |
e735f4d4 | 170 | </varlistentry> |
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171 | |
172 | <varlistentry> | |
173 | <term><option>--crash-reboot</option></term> | |
174 | ||
175 | <listitem><para>Automatically reboot the system on crash. This | |
176 | switch has no effect when running as user instance. This | |
177 | setting may also be enabled during boot, on the kernel command | |
178 | line via the <varname>systemd.crash_reboot=</varname> option, | |
179 | see below.</para></listitem> | |
180 | </varlistentry> | |
181 | ||
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182 | <varlistentry> |
183 | <term><option>--confirm-spawn</option></term> | |
184 | ||
185 | <listitem><para>Ask for confirmation when spawning processes. | |
186 | This switch has no effect when run as user | |
187 | instance.</para></listitem> | |
188 | </varlistentry> | |
189 | <varlistentry> | |
190 | <term><option>--show-status=</option></term> | |
191 | ||
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192 | <listitem><para>Takes a boolean argument or the special value <constant>auto</constant>. If on, terse unit |
193 | status information is shown on the console during boot-up and shutdown. If off, no such status information is | |
194 | shown. If set to <constant>auto</constant> behavior is similar to off, except that it is automatically switched | |
195 | to on, as soon as the first unit failure or significant boot delay is encountered. This switch has no effect | |
196 | when invoked as user instance. If specified, overrides both the kernel command line setting | |
197 | <varname>systemd.show_status=</varname> (see below) and the configuration file option | |
198 | <option>ShowStatus=</option>, see | |
199 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
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200 | </varlistentry> |
201 | <varlistentry> | |
202 | <term><option>--log-target=</option></term> | |
203 | ||
204 | <listitem><para>Set log target. Argument must be one of | |
205 | <option>console</option>, | |
206 | <option>journal</option>, | |
207 | <option>kmsg</option>, | |
208 | <option>journal-or-kmsg</option>, | |
209 | <option>null</option>.</para></listitem> | |
210 | </varlistentry> | |
211 | <varlistentry> | |
212 | <term><option>--log-level=</option></term> | |
213 | ||
214 | <listitem><para>Set log level. As | |
215 | argument this accepts a numerical log | |
216 | level or the well-known <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
217 | symbolic names (lowercase): | |
218 | <option>emerg</option>, | |
219 | <option>alert</option>, | |
220 | <option>crit</option>, | |
221 | <option>err</option>, | |
222 | <option>warning</option>, | |
223 | <option>notice</option>, | |
224 | <option>info</option>, | |
225 | <option>debug</option>.</para></listitem> | |
226 | </varlistentry> | |
227 | <varlistentry> | |
228 | <term><option>--log-color=</option></term> | |
229 | ||
230 | <listitem><para>Highlight important log messages. Argument is | |
231 | a boolean value. If the argument is omitted, it defaults to | |
232 | <option>true</option>.</para></listitem> | |
233 | </varlistentry> | |
234 | <varlistentry> | |
235 | <term><option>--log-location=</option></term> | |
236 | ||
237 | <listitem><para>Include code location in log messages. This is | |
238 | mostly relevant for debugging purposes. Argument is a boolean | |
239 | value. If the argument is omitted it defaults to | |
240 | <option>true</option>.</para></listitem> | |
241 | </varlistentry> | |
242 | <varlistentry> | |
243 | <term><option>--default-standard-output=</option></term> | |
244 | <term><option>--default-standard-error=</option></term> | |
245 | ||
246 | <listitem><para>Sets the default output or error output for | |
247 | all services and sockets, respectively. That is, controls the | |
248 | default for <option>StandardOutput=</option> and | |
249 | <option>StandardError=</option> (see | |
250 | <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
251 | for details). Takes one of | |
252 | <option>inherit</option>, | |
253 | <option>null</option>, | |
254 | <option>tty</option>, | |
255 | <option>journal</option>, | |
256 | <option>journal+console</option>, | |
257 | <option>syslog</option>, | |
258 | <option>syslog+console</option>, | |
259 | <option>kmsg</option>, | |
260 | <option>kmsg+console</option>. If the | |
261 | argument is omitted | |
262 | <option>--default-standard-output=</option> defaults to | |
263 | <option>journal</option> and | |
264 | <option>--default-standard-error=</option> to | |
265 | <option>inherit</option>.</para></listitem> | |
266 | </varlistentry> | |
267 | ||
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268 | <varlistentry> |
269 | <term><option>--machine-id=</option></term> | |
270 | ||
271 | <listitem><para>Override the machine-id set on the hard drive, | |
272 | useful for network booting or for containers. May not be set | |
273 | to all zeros.</para></listitem> | |
274 | </varlistentry> | |
275 | ||
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276 | <xi:include href="standard-options.xml" xpointer="help" /> |
277 | <xi:include href="standard-options.xml" xpointer="version" /> | |
278 | </variablelist> | |
279 | </refsect1> | |
280 | ||
281 | <refsect1> | |
282 | <title>Concepts</title> | |
283 | ||
284 | <para>systemd provides a dependency system between various | |
8a584da2 | 285 | entities called "units" of 11 different types. Units encapsulate |
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286 | various objects that are relevant for system boot-up and |
287 | maintenance. The majority of units are configured in unit | |
288 | configuration files, whose syntax and basic set of options is | |
289 | described in | |
290 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
291 | however some are created automatically from other configuration, | |
292 | dynamically from system state or programmatically at runtime. | |
2897b343 | 293 | Units may be "active" (meaning started, bound, plugged in, …, |
e735f4d4 | 294 | depending on the unit type, see below), or "inactive" (meaning |
2897b343 | 295 | stopped, unbound, unplugged, …), as well as in the process of |
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296 | being activated or deactivated, i.e. between the two states (these |
297 | states are called "activating", "deactivating"). A special | |
298 | "failed" state is available as well, which is very similar to | |
299 | "inactive" and is entered when the service failed in some way | |
300 | (process returned error code on exit, or crashed, or an operation | |
301 | timed out). If this state is entered, the cause will be logged, | |
302 | for later reference. Note that the various unit types may have a | |
303 | number of additional substates, which are mapped to the five | |
304 | generalized unit states described here.</para> | |
305 | ||
306 | <para>The following unit types are available:</para> | |
307 | ||
308 | <orderedlist> | |
309 | <listitem><para>Service units, which start and control daemons | |
db2df898 | 310 | and the processes they consist of. For details, see |
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311 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
312 | ||
313 | <listitem><para>Socket units, which encapsulate local IPC or | |
314 | network sockets in the system, useful for socket-based | |
db2df898 | 315 | activation. For details about socket units, see |
e735f4d4 MP |
316 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
317 | for details on socket-based activation and other forms of | |
318 | activation, see | |
319 | <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para></listitem> | |
320 | ||
321 | <listitem><para>Target units are useful to group units, or | |
322 | provide well-known synchronization points during boot-up, see | |
323 | <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
324 | ||
325 | <listitem><para>Device units expose kernel devices in systemd | |
326 | and may be used to implement device-based activation. For | |
db2df898 | 327 | details, see |
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328 | <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
329 | ||
330 | <listitem><para>Mount units control mount points in the file | |
331 | system, for details see | |
332 | <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
333 | ||
334 | <listitem><para>Automount units provide automount capabilities, | |
335 | for on-demand mounting of file systems as well as parallelized | |
336 | boot-up. See | |
337 | <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
338 | ||
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339 | <listitem><para>Timer units are useful for triggering activation |
340 | of other units based on timers. You may find details in | |
341 | <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
342 | ||
343 | <listitem><para>Swap units are very similar to mount units and | |
344 | encapsulate memory swap partitions or files of the operating | |
345 | system. They are described in | |
346 | <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
347 | ||
348 | <listitem><para>Path units may be used to activate other | |
349 | services when file system objects change or are modified. See | |
350 | <citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
351 | ||
352 | <listitem><para>Slice units may be used to group units which | |
353 | manage system processes (such as service and scope units) in a | |
354 | hierarchical tree for resource management purposes. See | |
355 | <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
356 | ||
357 | <listitem><para>Scope units are similar to service units, but | |
358 | manage foreign processes instead of starting them as well. See | |
359 | <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
360 | ||
361 | </orderedlist> | |
362 | ||
363 | <para>Units are named as their configuration files. Some units | |
364 | have special semantics. A detailed list is available in | |
365 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> | |
366 | ||
367 | <para>systemd knows various kinds of dependencies, including | |
368 | positive and negative requirement dependencies (i.e. | |
369 | <varname>Requires=</varname> and <varname>Conflicts=</varname>) as | |
370 | well as ordering dependencies (<varname>After=</varname> and | |
371 | <varname>Before=</varname>). NB: ordering and requirement | |
372 | dependencies are orthogonal. If only a requirement dependency | |
373 | exists between two units (e.g. <filename>foo.service</filename> | |
374 | requires <filename>bar.service</filename>), but no ordering | |
375 | dependency (e.g. <filename>foo.service</filename> after | |
376 | <filename>bar.service</filename>) and both are requested to start, | |
377 | they will be started in parallel. It is a common pattern that both | |
378 | requirement and ordering dependencies are placed between two | |
379 | units. Also note that the majority of dependencies are implicitly | |
380 | created and maintained by systemd. In most cases, it should be | |
381 | unnecessary to declare additional dependencies manually, however | |
382 | it is possible to do this.</para> | |
383 | ||
384 | <para>Application programs and units (via dependencies) may | |
385 | request state changes of units. In systemd, these requests are | |
386 | encapsulated as 'jobs' and maintained in a job queue. Jobs may | |
387 | succeed or can fail, their execution is ordered based on the | |
388 | ordering dependencies of the units they have been scheduled | |
389 | for.</para> | |
390 | ||
391 | <para>On boot systemd activates the target unit | |
392 | <filename>default.target</filename> whose job is to activate | |
393 | on-boot services and other on-boot units by pulling them in via | |
db2df898 | 394 | dependencies. Usually, the unit name is just an alias (symlink) for |
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395 | either <filename>graphical.target</filename> (for fully-featured |
396 | boots into the UI) or <filename>multi-user.target</filename> (for | |
397 | limited console-only boots for use in embedded or server | |
398 | environments, or similar; a subset of graphical.target). However, | |
399 | it is at the discretion of the administrator to configure it as an | |
400 | alias to any other target unit. See | |
401 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
402 | for details about these target units.</para> | |
403 | ||
404 | <para>Processes systemd spawns are placed in individual Linux | |
405 | control groups named after the unit which they belong to in the | |
406 | private systemd hierarchy. (see <ulink | |
407 | url="https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink> | |
408 | for more information about control groups, or short "cgroups"). | |
409 | systemd uses this to effectively keep track of processes. Control | |
410 | group information is maintained in the kernel, and is accessible | |
411 | via the file system hierarchy (beneath | |
412 | <filename>/sys/fs/cgroup/systemd/</filename>), or in tools such as | |
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413 | <citerefentry project='man-pages'><refentrytitle>systemd-cgls</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
414 | or | |
e735f4d4 MP |
415 | <citerefentry project='man-pages'><refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
416 | (<command>ps xawf -eo pid,user,cgroup,args</command> is | |
417 | particularly useful to list all processes and the systemd units | |
418 | they belong to.).</para> | |
419 | ||
420 | <para>systemd is compatible with the SysV init system to a large | |
421 | degree: SysV init scripts are supported and simply read as an | |
422 | alternative (though limited) configuration file format. The SysV | |
423 | <filename>/dev/initctl</filename> interface is provided, and | |
424 | compatibility implementations of the various SysV client tools are | |
425 | available. In addition to that, various established Unix | |
426 | functionality such as <filename>/etc/fstab</filename> or the | |
427 | <filename>utmp</filename> database are supported.</para> | |
428 | ||
429 | <para>systemd has a minimal transaction system: if a unit is | |
430 | requested to start up or shut down it will add it and all its | |
431 | dependencies to a temporary transaction. Then, it will verify if | |
432 | the transaction is consistent (i.e. whether the ordering of all | |
433 | units is cycle-free). If it is not, systemd will try to fix it up, | |
434 | and removes non-essential jobs from the transaction that might | |
435 | remove the loop. Also, systemd tries to suppress non-essential | |
436 | jobs in the transaction that would stop a running service. Finally | |
437 | it is checked whether the jobs of the transaction contradict jobs | |
438 | that have already been queued, and optionally the transaction is | |
439 | aborted then. If all worked out and the transaction is consistent | |
440 | and minimized in its impact it is merged with all already | |
441 | outstanding jobs and added to the run queue. Effectively this | |
442 | means that before executing a requested operation, systemd will | |
443 | verify that it makes sense, fixing it if possible, and only | |
444 | failing if it really cannot work.</para> | |
445 | ||
52ad194e | 446 | <para>systemd contains native implementations of various tasks |
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447 | that need to be executed as part of the boot process. For example, |
448 | it sets the hostname or configures the loopback network device. It | |
449 | also sets up and mounts various API file systems, such as | |
450 | <filename>/sys</filename> or <filename>/proc</filename>.</para> | |
451 | ||
452 | <para>For more information about the concepts and | |
453 | ideas behind systemd, please refer to the | |
454 | <ulink url="http://0pointer.de/blog/projects/systemd.html">Original Design Document</ulink>.</para> | |
455 | ||
456 | <para>Note that some but not all interfaces provided | |
457 | by systemd are covered by the | |
2897b343 | 458 | <ulink url="https://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface |
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459 | Stability Promise</ulink>.</para> |
460 | ||
461 | <para>Units may be generated dynamically at boot and system | |
462 | manager reload time, for example based on other configuration | |
db2df898 | 463 | files or parameters passed on the kernel command line. For details, see |
e3bff60a | 464 | <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> |
e735f4d4 MP |
465 | |
466 | <para>Systems which invoke systemd in a container or initrd | |
467 | environment should implement the | |
2897b343 MP |
468 | <ulink url="https://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container Interface</ulink> or |
469 | <ulink url="https://www.freedesktop.org/wiki/Software/systemd/InitrdInterface">initrd Interface</ulink> | |
e735f4d4 MP |
470 | specifications, respectively.</para> |
471 | </refsect1> | |
472 | ||
473 | <refsect1> | |
474 | <title>Directories</title> | |
475 | ||
476 | <variablelist> | |
477 | <varlistentry> | |
478 | <term>System unit directories</term> | |
479 | ||
480 | <listitem><para>The systemd system manager reads unit | |
481 | configuration from various directories. Packages that want to | |
482 | install unit files shall place them in the directory returned | |
483 | by <command>pkg-config systemd | |
484 | --variable=systemdsystemunitdir</command>. Other directories | |
485 | checked are <filename>/usr/local/lib/systemd/system</filename> | |
486 | and <filename>/usr/lib/systemd/system</filename>. User | |
487 | configuration always takes precedence. <command>pkg-config | |
488 | systemd --variable=systemdsystemconfdir</command> returns the | |
489 | path of the system configuration directory. Packages should | |
490 | alter the content of these directories only with the | |
491 | <command>enable</command> and <command>disable</command> | |
492 | commands of the | |
493 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
494 | tool. Full list of directories is provided in | |
495 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. | |
496 | </para></listitem> | |
497 | </varlistentry> | |
498 | </variablelist> | |
499 | ||
500 | <variablelist> | |
501 | <varlistentry> | |
502 | <term>User unit directories</term> | |
503 | ||
504 | <listitem><para>Similar rules apply for the user unit | |
505 | directories. However, here the | |
506 | <ulink url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG | |
507 | Base Directory specification</ulink> is followed to find | |
508 | units. Applications should place their unit files in the | |
509 | directory returned by <command>pkg-config systemd | |
510 | --variable=systemduserunitdir</command>. Global configuration | |
511 | is done in the directory reported by <command>pkg-config | |
512 | systemd --variable=systemduserconfdir</command>. The | |
513 | <command>enable</command> and <command>disable</command> | |
514 | commands of the | |
515 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
516 | tool can handle both global (i.e. for all users) and private | |
517 | (for one user) enabling/disabling of units. Full list of | |
518 | directories is provided in | |
519 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. | |
520 | </para></listitem> | |
521 | </varlistentry> | |
522 | </variablelist> | |
523 | ||
524 | <variablelist> | |
525 | <varlistentry> | |
526 | <term>SysV init scripts directory</term> | |
527 | ||
528 | <listitem><para>The location of the SysV init script directory | |
529 | varies between distributions. If systemd cannot find a native | |
530 | unit file for a requested service, it will look for a SysV | |
531 | init script of the same name (with the | |
532 | <filename>.service</filename> suffix | |
533 | removed).</para></listitem> | |
534 | </varlistentry> | |
535 | </variablelist> | |
536 | ||
537 | <variablelist> | |
538 | <varlistentry> | |
539 | <term>SysV runlevel link farm directory</term> | |
540 | ||
541 | <listitem><para>The location of the SysV runlevel link farm | |
542 | directory varies between distributions. systemd will take the | |
543 | link farm into account when figuring out whether a service | |
544 | shall be enabled. Note that a service unit with a native unit | |
545 | configuration file cannot be started by activating it in the | |
546 | SysV runlevel link farm.</para></listitem> | |
547 | </varlistentry> | |
548 | </variablelist> | |
549 | </refsect1> | |
550 | ||
551 | <refsect1> | |
552 | <title>Signals</title> | |
553 | ||
554 | <variablelist> | |
555 | <varlistentry> | |
556 | <term><constant>SIGTERM</constant></term> | |
557 | ||
558 | <listitem><para>Upon receiving this signal the systemd system | |
559 | manager serializes its state, reexecutes itself and | |
560 | deserializes the saved state again. This is mostly equivalent | |
561 | to <command>systemctl daemon-reexec</command>.</para> | |
562 | ||
563 | <para>systemd user managers will start the | |
564 | <filename>exit.target</filename> unit when this signal is | |
565 | received. This is mostly equivalent to <command>systemctl | |
f5e65279 MB |
566 | --user start exit.target |
567 | --job-mode=replace-irreversible</command>.</para></listitem> | |
e735f4d4 MP |
568 | </varlistentry> |
569 | ||
570 | <varlistentry> | |
571 | <term><constant>SIGINT</constant></term> | |
572 | ||
573 | <listitem><para>Upon receiving this signal the systemd system | |
574 | manager will start the | |
575 | <filename>ctrl-alt-del.target</filename> unit. This is mostly | |
f5e65279 MB |
576 | equivalent to <command>systemctl start ctl-alt-del.target |
577 | --job-mode=replace-irreversible</command>. If this signal is | |
578 | received more than 7 times per 2s, an immediate reboot is | |
579 | triggered. Note that pressing Ctrl-Alt-Del on the console | |
580 | will trigger this signal. Hence, if a reboot is hanging, | |
581 | pressing Ctrl-Alt-Del more than 7 times in 2s is a relatively | |
582 | safe way to trigger an immediate reboot.</para> | |
e735f4d4 MP |
583 | |
584 | <para>systemd user managers treat this signal the same way as | |
585 | <constant>SIGTERM</constant>.</para></listitem> | |
586 | </varlistentry> | |
587 | ||
588 | <varlistentry> | |
589 | <term><constant>SIGWINCH</constant></term> | |
590 | ||
591 | <listitem><para>When this signal is received the systemd | |
592 | system manager will start the | |
593 | <filename>kbrequest.target</filename> unit. This is mostly | |
594 | equivalent to <command>systemctl start | |
595 | kbrequest.target</command>.</para> | |
596 | ||
597 | <para>This signal is ignored by systemd user | |
598 | managers.</para></listitem> | |
599 | </varlistentry> | |
600 | ||
601 | <varlistentry> | |
602 | <term><constant>SIGPWR</constant></term> | |
603 | ||
604 | <listitem><para>When this signal is received the systemd | |
605 | manager will start the <filename>sigpwr.target</filename> | |
606 | unit. This is mostly equivalent to <command>systemctl start | |
607 | sigpwr.target</command>.</para></listitem> | |
608 | </varlistentry> | |
609 | ||
610 | <varlistentry> | |
611 | <term><constant>SIGUSR1</constant></term> | |
612 | ||
613 | <listitem><para>When this signal is received the systemd | |
614 | manager will try to reconnect to the D-Bus | |
615 | bus.</para></listitem> | |
616 | </varlistentry> | |
617 | ||
618 | <varlistentry> | |
619 | <term><constant>SIGUSR2</constant></term> | |
620 | ||
621 | <listitem><para>When this signal is received the systemd | |
db2df898 | 622 | manager will log its complete state in human-readable form. |
e735f4d4 MP |
623 | The data logged is the same as printed by |
624 | <command>systemd-analyze dump</command>.</para></listitem> | |
625 | </varlistentry> | |
626 | ||
627 | <varlistentry> | |
628 | <term><constant>SIGHUP</constant></term> | |
629 | ||
630 | <listitem><para>Reloads the complete daemon configuration. | |
631 | This is mostly equivalent to <command>systemctl | |
632 | daemon-reload</command>.</para></listitem> | |
633 | </varlistentry> | |
634 | ||
635 | <varlistentry> | |
636 | <term><constant>SIGRTMIN+0</constant></term> | |
637 | ||
638 | <listitem><para>Enters default mode, starts the | |
639 | <filename>default.target</filename> unit. This is mostly | |
f5e65279 | 640 | equivalent to <command>systemctl isolate |
e735f4d4 MP |
641 | default.target</command>.</para></listitem> |
642 | </varlistentry> | |
643 | ||
644 | <varlistentry> | |
645 | <term><constant>SIGRTMIN+1</constant></term> | |
646 | ||
647 | <listitem><para>Enters rescue mode, starts the | |
648 | <filename>rescue.target</filename> unit. This is mostly | |
649 | equivalent to <command>systemctl isolate | |
650 | rescue.target</command>.</para></listitem> | |
651 | </varlistentry> | |
652 | ||
653 | <varlistentry> | |
654 | <term><constant>SIGRTMIN+2</constant></term> | |
655 | ||
656 | <listitem><para>Enters emergency mode, starts the | |
657 | <filename>emergency.service</filename> unit. This is mostly | |
658 | equivalent to <command>systemctl isolate | |
659 | emergency.service</command>.</para></listitem> | |
660 | </varlistentry> | |
661 | ||
662 | <varlistentry> | |
663 | <term><constant>SIGRTMIN+3</constant></term> | |
664 | ||
665 | <listitem><para>Halts the machine, starts the | |
666 | <filename>halt.target</filename> unit. This is mostly | |
f5e65279 MB |
667 | equivalent to <command>systemctl start halt.target |
668 | --job-mode=replace-irreversible</command>.</para> | |
669 | </listitem> | |
e735f4d4 MP |
670 | </varlistentry> |
671 | ||
672 | <varlistentry> | |
673 | <term><constant>SIGRTMIN+4</constant></term> | |
674 | ||
675 | <listitem><para>Powers off the machine, starts the | |
676 | <filename>poweroff.target</filename> unit. This is mostly | |
f5e65279 MB |
677 | equivalent to <command>systemctl start poweroff.target |
678 | --job-mode=replace-irreversible</command>.</para> | |
679 | </listitem> | |
e735f4d4 MP |
680 | </varlistentry> |
681 | ||
682 | <varlistentry> | |
683 | <term><constant>SIGRTMIN+5</constant></term> | |
684 | ||
685 | <listitem><para>Reboots the machine, starts the | |
686 | <filename>reboot.target</filename> unit. This is mostly | |
f5e65279 MB |
687 | equivalent to <command>systemctl start reboot.target |
688 | --job-mode=replace-irreversible</command>.</para> | |
689 | </listitem> | |
e735f4d4 MP |
690 | </varlistentry> |
691 | ||
692 | <varlistentry> | |
693 | <term><constant>SIGRTMIN+6</constant></term> | |
694 | ||
695 | <listitem><para>Reboots the machine via kexec, starts the | |
696 | <filename>kexec.target</filename> unit. This is mostly | |
f5e65279 MB |
697 | equivalent to <command>systemctl start kexec.target |
698 | --job-mode=replace-irreversible</command>.</para> | |
699 | </listitem> | |
e735f4d4 MP |
700 | </varlistentry> |
701 | ||
702 | <varlistentry> | |
703 | <term><constant>SIGRTMIN+13</constant></term> | |
704 | ||
705 | <listitem><para>Immediately halts the machine.</para></listitem> | |
706 | </varlistentry> | |
707 | ||
708 | <varlistentry> | |
709 | <term><constant>SIGRTMIN+14</constant></term> | |
710 | ||
711 | <listitem><para>Immediately powers off the machine.</para></listitem> | |
712 | </varlistentry> | |
713 | ||
714 | <varlistentry> | |
715 | <term><constant>SIGRTMIN+15</constant></term> | |
716 | ||
717 | <listitem><para>Immediately reboots the machine.</para></listitem> | |
718 | </varlistentry> | |
719 | ||
720 | <varlistentry> | |
721 | <term><constant>SIGRTMIN+16</constant></term> | |
722 | ||
723 | <listitem><para>Immediately reboots the machine with kexec.</para></listitem> | |
724 | </varlistentry> | |
725 | ||
726 | <varlistentry> | |
727 | <term><constant>SIGRTMIN+20</constant></term> | |
728 | ||
729 | <listitem><para>Enables display of status messages on the | |
730 | console, as controlled via | |
731 | <varname>systemd.show_status=1</varname> on the kernel command | |
732 | line.</para></listitem> | |
733 | </varlistentry> | |
734 | ||
735 | <varlistentry> | |
736 | <term><constant>SIGRTMIN+21</constant></term> | |
737 | ||
738 | <listitem><para>Disables display of | |
739 | status messages on the console, as | |
740 | controlled via | |
741 | <varname>systemd.show_status=0</varname> | |
742 | on the kernel command | |
743 | line.</para></listitem> | |
744 | </varlistentry> | |
745 | ||
746 | <varlistentry> | |
747 | <term><constant>SIGRTMIN+22</constant></term> | |
748 | <term><constant>SIGRTMIN+23</constant></term> | |
749 | ||
750 | <listitem><para>Sets the log level to <literal>debug</literal> | |
751 | (or <literal>info</literal> on | |
752 | <constant>SIGRTMIN+23</constant>), as controlled via | |
753 | <varname>systemd.log_level=debug</varname> (or | |
754 | <varname>systemd.log_level=info</varname> on | |
755 | <constant>SIGRTMIN+23</constant>) on the kernel command | |
756 | line.</para></listitem> | |
757 | </varlistentry> | |
758 | ||
759 | <varlistentry> | |
760 | <term><constant>SIGRTMIN+24</constant></term> | |
761 | ||
762 | <listitem><para>Immediately exits the manager (only available | |
763 | for --user instances).</para></listitem> | |
764 | </varlistentry> | |
765 | ||
766 | <varlistentry> | |
767 | <term><constant>SIGRTMIN+26</constant></term> | |
768 | <term><constant>SIGRTMIN+27</constant></term> | |
769 | <term><constant>SIGRTMIN+28</constant></term> | |
770 | ||
2897b343 | 771 | <listitem><para>Sets the log target to |
e735f4d4 MP |
772 | <literal>journal-or-kmsg</literal> (or |
773 | <literal>console</literal> on | |
774 | <constant>SIGRTMIN+27</constant>, <literal>kmsg</literal> on | |
775 | <constant>SIGRTMIN+28</constant>), as controlled via | |
776 | <varname>systemd.log_target=journal-or-kmsg</varname> (or | |
777 | <varname>systemd.log_target=console</varname> on | |
778 | <constant>SIGRTMIN+27</constant> or | |
779 | <varname>systemd.log_target=kmsg</varname> on | |
780 | <constant>SIGRTMIN+28</constant>) on the kernel command | |
781 | line.</para></listitem> | |
782 | </varlistentry> | |
783 | </variablelist> | |
784 | </refsect1> | |
785 | ||
786 | <refsect1> | |
787 | <title>Environment</title> | |
788 | ||
789 | <variablelist class='environment-variables'> | |
790 | <varlistentry> | |
791 | <term><varname>$SYSTEMD_LOG_LEVEL</varname></term> | |
792 | <listitem><para>systemd reads the log level from this | |
793 | environment variable. This can be overridden with | |
794 | <option>--log-level=</option>.</para></listitem> | |
795 | </varlistentry> | |
796 | ||
797 | <varlistentry> | |
798 | <term><varname>$SYSTEMD_LOG_TARGET</varname></term> | |
799 | <listitem><para>systemd reads the log target from this | |
800 | environment variable. This can be overridden with | |
801 | <option>--log-target=</option>.</para></listitem> | |
802 | </varlistentry> | |
803 | ||
804 | <varlistentry> | |
805 | <term><varname>$SYSTEMD_LOG_COLOR</varname></term> | |
806 | <listitem><para>Controls whether systemd highlights important | |
807 | log messages. This can be overridden with | |
808 | <option>--log-color=</option>.</para></listitem> | |
809 | </varlistentry> | |
810 | ||
811 | <varlistentry> | |
812 | <term><varname>$SYSTEMD_LOG_LOCATION</varname></term> | |
813 | <listitem><para>Controls whether systemd prints the code | |
814 | location along with log messages. This can be overridden with | |
815 | <option>--log-location=</option>.</para></listitem> | |
816 | </varlistentry> | |
817 | ||
818 | <varlistentry> | |
819 | <term><varname>$XDG_CONFIG_HOME</varname></term> | |
820 | <term><varname>$XDG_CONFIG_DIRS</varname></term> | |
821 | <term><varname>$XDG_DATA_HOME</varname></term> | |
822 | <term><varname>$XDG_DATA_DIRS</varname></term> | |
823 | ||
824 | <listitem><para>The systemd user manager uses these variables | |
825 | in accordance to the <ulink | |
826 | url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG | |
827 | Base Directory specification</ulink> to find its | |
828 | configuration.</para></listitem> | |
829 | </varlistentry> | |
830 | ||
831 | <varlistentry> | |
832 | <term><varname>$SYSTEMD_UNIT_PATH</varname></term> | |
833 | ||
834 | <listitem><para>Controls where systemd looks for unit | |
835 | files.</para></listitem> | |
836 | </varlistentry> | |
837 | ||
838 | <varlistentry> | |
839 | <term><varname>$SYSTEMD_SYSVINIT_PATH</varname></term> | |
840 | ||
841 | <listitem><para>Controls where systemd looks for SysV init | |
842 | scripts.</para></listitem> | |
843 | </varlistentry> | |
844 | ||
845 | <varlistentry> | |
846 | <term><varname>$SYSTEMD_SYSVRCND_PATH</varname></term> | |
847 | ||
848 | <listitem><para>Controls where systemd looks for SysV init | |
849 | script runlevel link farms.</para></listitem> | |
850 | </varlistentry> | |
851 | ||
4c89c718 MP |
852 | <varlistentry> |
853 | <term><varname>$SYSTEMD_COLORS</varname></term> | |
854 | ||
8a584da2 MP |
855 | <listitem><para>The value must be a boolean. Controls whether colorized output should be |
856 | generated. This can be specified to override the decision that <command>systemd</command> | |
857 | makes based on <varname>$TERM</varname> and what the console is connected to.</para> | |
858 | </listitem> | |
4c89c718 MP |
859 | </varlistentry> |
860 | ||
e735f4d4 MP |
861 | <varlistentry> |
862 | <term><varname>$LISTEN_PID</varname></term> | |
863 | <term><varname>$LISTEN_FDS</varname></term> | |
6300502b | 864 | <term><varname>$LISTEN_FDNAMES</varname></term> |
e735f4d4 MP |
865 | |
866 | <listitem><para>Set by systemd for supervised processes during | |
867 | socket-based activation. See | |
868 | <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
8a584da2 | 869 | for more information.</para></listitem> |
e735f4d4 MP |
870 | </varlistentry> |
871 | ||
872 | <varlistentry> | |
873 | <term><varname>$NOTIFY_SOCKET</varname></term> | |
874 | ||
875 | <listitem><para>Set by systemd for supervised processes for | |
876 | status and start-up completion notification. See | |
877 | <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
8a584da2 | 878 | for more information.</para></listitem> |
e735f4d4 MP |
879 | </varlistentry> |
880 | </variablelist> | |
881 | </refsect1> | |
882 | ||
883 | <refsect1> | |
884 | <title>Kernel Command Line</title> | |
885 | ||
886 | <para>When run as system instance systemd parses a number of | |
887 | kernel command line arguments<footnote><para>If run inside a Linux | |
888 | container these arguments may be passed as command line arguments | |
889 | to systemd itself, next to any of the command line options listed | |
890 | in the Options section above. If run outside of Linux containers, | |
891 | these arguments are parsed from <filename>/proc/cmdline</filename> | |
892 | instead.</para></footnote>:</para> | |
893 | ||
894 | <variablelist class='kernel-commandline-options'> | |
895 | <varlistentry> | |
896 | <term><varname>systemd.unit=</varname></term> | |
897 | <term><varname>rd.systemd.unit=</varname></term> | |
898 | ||
899 | <listitem><para>Overrides the unit to activate on boot. | |
900 | Defaults to <filename>default.target</filename>. This may be | |
901 | used to temporarily boot into a different boot unit, for | |
902 | example <filename>rescue.target</filename> or | |
903 | <filename>emergency.service</filename>. See | |
904 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
905 | for details about these units. The option prefixed with | |
906 | <literal>rd.</literal> is honored only in the initial RAM disk | |
907 | (initrd), while the one that is not prefixed only in the main | |
908 | system.</para></listitem> | |
909 | </varlistentry> | |
910 | ||
911 | <varlistentry> | |
2897b343 | 912 | <term><varname>systemd.dump_core</varname></term> |
e735f4d4 | 913 | |
2897b343 MP |
914 | <listitem><para>Takes a boolean argument or enables the option if specified |
915 | without an argument. If enabled, the systemd manager (PID 1) dumps core when | |
916 | it crashes. Otherwise, no core dump is created. Defaults to enabled.</para> | |
917 | </listitem> | |
6300502b MP |
918 | </varlistentry> |
919 | ||
920 | <varlistentry> | |
2897b343 | 921 | <term><varname>systemd.crash_chvt</varname></term> |
6300502b | 922 | |
2897b343 MP |
923 | <listitem><para>Takes a positive integer, or a boolean argument. Can be also |
924 | specified without an argument, with the same effect as a positive boolean. If | |
925 | a positive integer (in the range 1–63) is specified, the system manager (PID | |
926 | 1) will activate the specified virtual terminal (VT) when it | |
927 | crashes. Defaults to disabled, meaning that no such switch is attempted. If | |
928 | set to enabled, the VT the kernel messages are written to is selected. | |
929 | </para></listitem> | |
e735f4d4 MP |
930 | </varlistentry> |
931 | ||
932 | <varlistentry> | |
2897b343 | 933 | <term><varname>systemd.crash_shell</varname></term> |
e735f4d4 | 934 | |
2897b343 MP |
935 | <listitem><para>Takes a boolean argument or enables the option if specified |
936 | without an argument. If enabled, the system manager (PID 1) spawns a shell | |
937 | when it crashes, after a 10s delay. Otherwise, no shell is spawned. Defaults | |
938 | to disabled, for security reasons, as the shell is not protected by password | |
e735f4d4 MP |
939 | authentication.</para></listitem> |
940 | </varlistentry> | |
941 | ||
942 | <varlistentry> | |
2897b343 | 943 | <term><varname>systemd.crash_reboot</varname></term> |
e735f4d4 | 944 | |
2897b343 MP |
945 | <listitem><para>Takes a boolean argument or enables the option if specified |
946 | without an argument. If enabled, the system manager (PID 1) will reboot the | |
947 | machine automatically when it crashes, after a 10s delay. Otherwise, the | |
948 | system will hang indefinitely. Defaults to disabled, in order to avoid a | |
949 | reboot loop. If combined with <varname>systemd.crash_shell</varname>, the | |
6300502b | 950 | system is rebooted after the shell exits.</para></listitem> |
e735f4d4 MP |
951 | </varlistentry> |
952 | ||
953 | <varlistentry> | |
2897b343 | 954 | <term><varname>systemd.confirm_spawn</varname></term> |
e735f4d4 | 955 | |
2897b343 MP |
956 | <listitem><para>Takes a boolean argument or a path to the virtual console |
957 | where the confirmation messages should be emitted. Can be also specified | |
958 | without an argument, with the same effect as a positive boolean. If enabled, | |
959 | the system manager (PID 1) asks for confirmation when spawning processes | |
960 | using <option>/dev/console</option>. If a path or a console name (such as | |
961 | <literal>ttyS0</literal>) is provided, the virtual console pointed to by this | |
962 | path or described by the give name will be used instead. Defaults to disabled. | |
963 | </para></listitem> | |
e735f4d4 MP |
964 | </varlistentry> |
965 | ||
966 | <varlistentry> | |
2897b343 | 967 | <term><varname>systemd.show_status</varname></term> |
e735f4d4 MP |
968 | |
969 | <listitem><para>Takes a boolean argument or the constant | |
2897b343 MP |
970 | <constant>auto</constant>. Can be also specified without an argument, with |
971 | the same effect as a positive boolean. If enabled, the systemd manager (PID | |
972 | 1) shows terse service status updates on the console during bootup. | |
973 | <constant>auto</constant> behaves like <option>false</option> until a unit | |
974 | fails or there is a significant delay in boot. Defaults to enabled, unless | |
975 | <option>quiet</option> is passed as kernel command line option, in which case | |
976 | it defaults to <constant>auto</constant>. If specified overrides the system | |
977 | manager configuration file option <option>ShowStatus=</option>, see | |
978 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. | |
979 | However, the process command line option <option>--show-status=</option> | |
980 | takes precedence over both this kernel command line option and the | |
981 | configuration file option.</para></listitem> | |
e735f4d4 MP |
982 | </varlistentry> |
983 | ||
984 | <varlistentry> | |
985 | <term><varname>systemd.log_target=</varname></term> | |
986 | <term><varname>systemd.log_level=</varname></term> | |
e735f4d4 | 987 | <term><varname>systemd.log_location=</varname></term> |
2897b343 | 988 | <term><varname>systemd.log_color</varname></term> |
e735f4d4 | 989 | |
2897b343 MP |
990 | <listitem><para>Controls log output, with the same effect as the |
991 | <varname>$SYSTEMD_LOG_TARGET</varname>, | |
e735f4d4 | 992 | <varname>$SYSTEMD_LOG_LEVEL</varname>, |
2897b343 MP |
993 | <varname>$SYSTEMD_LOG_LOCATION</varname>, |
994 | <varname>$SYSTEMD_LOG_COLOR</varname> environment variables described above. | |
995 | <varname>systemd.log_color</varname> can be specified without an argument, | |
996 | with the same effect as a positive boolean.</para></listitem> | |
e735f4d4 MP |
997 | </varlistentry> |
998 | ||
999 | <varlistentry> | |
1000 | <term><varname>systemd.default_standard_output=</varname></term> | |
1001 | <term><varname>systemd.default_standard_error=</varname></term> | |
1002 | <listitem><para>Controls default standard output and error | |
1003 | output for services, with the same effect as the | |
1004 | <option>--default-standard-output=</option> and | |
1005 | <option>--default-standard-error=</option> command line | |
1006 | arguments described above, respectively.</para></listitem> | |
1007 | </varlistentry> | |
1008 | ||
1009 | <varlistentry> | |
1010 | <term><varname>systemd.setenv=</varname></term> | |
1011 | ||
1012 | <listitem><para>Takes a string argument in the form | |
1013 | VARIABLE=VALUE. May be used to set default environment | |
1014 | variables to add to forked child processes. May be used more | |
1015 | than once to set multiple variables.</para></listitem> | |
1016 | </varlistentry> | |
1017 | ||
4c89c718 MP |
1018 | <varlistentry> |
1019 | <term><varname>systemd.machine_id=</varname></term> | |
1020 | ||
1021 | <listitem><para>Takes a 32 character hex value to be | |
1022 | used for setting the machine-id. Intended mostly for | |
1023 | network booting where the same machine-id is desired | |
1024 | for every boot.</para></listitem> | |
1025 | </varlistentry> | |
1026 | ||
2897b343 MP |
1027 | <varlistentry> |
1028 | <term><varname>systemd.unified_cgroup_hierarchy</varname></term> | |
1029 | ||
1030 | <listitem><para>When specified without an argument or with a true argument, | |
1031 | enables the usage of | |
1032 | <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">unified cgroup hierarchy</ulink> | |
1033 | (a.k.a. cgroups-v2). When specified with a false argument, fall back to | |
1034 | hybrid or full legacy cgroup hierarchy.</para> | |
1035 | ||
1036 | <para>If this option is not specified, the default behaviour is determined | |
1037 | during compilation (the <option>--with-default-hierarchy=</option> | |
1038 | option). If the kernel does not support unified cgroup hierarchy, the legacy | |
1039 | hierarchy will be used even if this option is specified.</para> | |
1040 | </listitem> | |
1041 | </varlistentry> | |
1042 | ||
1043 | <varlistentry> | |
1044 | <term><varname>systemd.legacy_systemd_cgroup_controller</varname></term> | |
1045 | ||
1046 | <listitem><para>Takes effect if the full unified cgroup hierarchy is not used | |
1047 | (see previous option). When specified without an argument or with a true | |
1048 | argument, disables the use of "hybrid" cgroup hierarchy (i.e. a cgroups-v2 | |
1049 | tree used for systemd, and | |
1050 | <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v1/">legacy | |
1051 | cgroup hierarchy</ulink>, a.k.a. cgroups-v1, for other controllers), and | |
1052 | forces a full "legacy" mode. When specified with a false argument, enables | |
1053 | the use of "hybrid" hierarchy.</para> | |
1054 | ||
1055 | <para>If this option is not specified, the default behaviour is determined | |
1056 | during compilation (the <option>--with-default-hierarchy=</option> | |
1057 | option). If the kernel does not support unified cgroup hierarchy, the legacy | |
1058 | hierarchy will be used even if this option is specified.</para> | |
1059 | </listitem> | |
1060 | </varlistentry> | |
1061 | ||
e735f4d4 MP |
1062 | <varlistentry> |
1063 | <term><varname>quiet</varname></term> | |
1064 | ||
1065 | <listitem><para>Turn off status output at boot, much like | |
1066 | <varname>systemd.show_status=false</varname> would. Note that | |
1067 | this option is also read by the kernel itself and disables | |
1068 | kernel log output. Passing this option hence turns off the | |
1069 | usual output from both the system manager and the kernel. | |
1070 | </para></listitem> | |
1071 | </varlistentry> | |
1072 | ||
1073 | <varlistentry> | |
1074 | <term><varname>debug</varname></term> | |
1075 | ||
1076 | <listitem><para>Turn on debugging output. This is equivalent | |
1077 | to <varname>systemd.log_level=debug</varname>. Note that this | |
1078 | option is also read by the kernel itself and enables kernel | |
1079 | debug output. Passing this option hence turns on the debug | |
1080 | output from both the system manager and the | |
1081 | kernel.</para></listitem> | |
1082 | </varlistentry> | |
1083 | ||
1084 | <varlistentry> | |
1085 | <term><varname>emergency</varname></term> | |
5a920b42 | 1086 | <term><varname>rd.emergency</varname></term> |
e735f4d4 MP |
1087 | <term><varname>-b</varname></term> |
1088 | ||
1089 | <listitem><para>Boot into emergency mode. This is equivalent | |
5a920b42 MP |
1090 | to <varname>systemd.unit=emergency.target</varname> or |
1091 | <varname>rd.systemd.unit=emergency.target</varname>, respectively, and | |
1092 | provided for compatibility reasons and to be easier to type.</para></listitem> | |
e735f4d4 MP |
1093 | </varlistentry> |
1094 | ||
1095 | <varlistentry> | |
1096 | <term><varname>rescue</varname></term> | |
5a920b42 | 1097 | <term><varname>rd.rescue</varname></term> |
e735f4d4 MP |
1098 | <term><varname>single</varname></term> |
1099 | <term><varname>s</varname></term> | |
1100 | <term><varname>S</varname></term> | |
1101 | <term><varname>1</varname></term> | |
1102 | ||
1103 | <listitem><para>Boot into rescue mode. This is equivalent to | |
5a920b42 MP |
1104 | <varname>systemd.unit=rescue.target</varname> or |
1105 | <varname>rd.systemd.unit=rescue.target</varname>, respectively, and | |
1106 | provided for compatibility reasons and to be easier to type.</para></listitem> | |
e735f4d4 MP |
1107 | </varlistentry> |
1108 | ||
1109 | <varlistentry> | |
1110 | <term><varname>2</varname></term> | |
1111 | <term><varname>3</varname></term> | |
1112 | <term><varname>4</varname></term> | |
1113 | <term><varname>5</varname></term> | |
1114 | ||
1115 | <listitem><para>Boot into the specified legacy SysV runlevel. | |
1116 | These are equivalent to | |
1117 | <varname>systemd.unit=runlevel2.target</varname>, | |
1118 | <varname>systemd.unit=runlevel3.target</varname>, | |
1119 | <varname>systemd.unit=runlevel4.target</varname>, and | |
1120 | <varname>systemd.unit=runlevel5.target</varname>, | |
1121 | respectively, and provided for compatibility reasons and to be | |
1122 | easier to type.</para></listitem> | |
1123 | </varlistentry> | |
1124 | ||
1125 | <varlistentry> | |
1126 | <term><varname>locale.LANG=</varname></term> | |
1127 | <term><varname>locale.LANGUAGE=</varname></term> | |
1128 | <term><varname>locale.LC_CTYPE=</varname></term> | |
1129 | <term><varname>locale.LC_NUMERIC=</varname></term> | |
1130 | <term><varname>locale.LC_TIME=</varname></term> | |
1131 | <term><varname>locale.LC_COLLATE=</varname></term> | |
1132 | <term><varname>locale.LC_MONETARY=</varname></term> | |
1133 | <term><varname>locale.LC_MESSAGES=</varname></term> | |
1134 | <term><varname>locale.LC_PAPER=</varname></term> | |
1135 | <term><varname>locale.LC_NAME=</varname></term> | |
1136 | <term><varname>locale.LC_ADDRESS=</varname></term> | |
1137 | <term><varname>locale.LC_TELEPHONE=</varname></term> | |
1138 | <term><varname>locale.LC_MEASUREMENT=</varname></term> | |
1139 | <term><varname>locale.LC_IDENTIFICATION=</varname></term> | |
1140 | ||
1141 | <listitem><para>Set the system locale to use. This overrides | |
1142 | the settings in <filename>/etc/locale.conf</filename>. For | |
db2df898 | 1143 | more information, see |
e3bff60a | 1144 | <citerefentry project='man-pages'><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
e735f4d4 | 1145 | and |
e3bff60a | 1146 | <citerefentry project='man-pages'><refentrytitle>locale</refentrytitle><manvolnum>7</manvolnum></citerefentry>. |
e735f4d4 MP |
1147 | </para></listitem> |
1148 | </varlistentry> | |
1149 | </variablelist> | |
1150 | ||
1151 | <para>For other kernel command line parameters understood by | |
1152 | components of the core OS, please refer to | |
1153 | <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> | |
1154 | </refsect1> | |
1155 | ||
1156 | <refsect1> | |
1157 | <title>Sockets and FIFOs</title> | |
1158 | ||
1159 | <variablelist> | |
1160 | <varlistentry> | |
1161 | <term><filename>/run/systemd/notify</filename></term> | |
1162 | ||
1163 | <listitem><para>Daemon status notification socket. This is an | |
1164 | <constant>AF_UNIX</constant> datagram socket and is used to | |
1165 | implement the daemon notification logic as implemented by | |
1166 | <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem> | |
1167 | ||
1168 | </varlistentry> | |
1169 | ||
e735f4d4 MP |
1170 | <varlistentry> |
1171 | <term><filename>/run/systemd/private</filename></term> | |
1172 | ||
1173 | <listitem><para>Used internally as communication channel | |
1174 | between | |
1175 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
1176 | and the systemd process. This is an | |
1177 | <constant>AF_UNIX</constant> stream socket. This interface is | |
1178 | private to systemd and should not be used in external | |
1179 | projects.</para></listitem> | |
1180 | </varlistentry> | |
1181 | ||
1182 | <varlistentry> | |
1183 | <term><filename>/dev/initctl</filename></term> | |
1184 | ||
1185 | <listitem><para>Limited compatibility support for the SysV | |
1186 | client interface, as implemented by the | |
1187 | <filename>systemd-initctl.service</filename> unit. This is a | |
1188 | named pipe in the file system. This interface is obsolete and | |
1189 | should not be used in new applications.</para></listitem> | |
1190 | </varlistentry> | |
1191 | </variablelist> | |
1192 | </refsect1> | |
1193 | ||
1194 | <refsect1> | |
1195 | <title>See Also</title> | |
1196 | <para> | |
2897b343 | 1197 | The <ulink url="https://www.freedesktop.org/wiki/Software/systemd/">systemd Homepage</ulink>, |
e735f4d4 | 1198 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
e3bff60a | 1199 | <citerefentry project='man-pages'><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
e735f4d4 MP |
1200 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
1201 | <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
1202 | <citerefentry><refentrytitle>systemd-notify</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
1203 | <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>, | |
1204 | <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
1205 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
1206 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
1207 | <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
1208 | <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>, | |
1209 | <citerefentry project='man-pages'><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>, | |
1210 | <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
1211 | </para> | |
1212 | </refsect1> | |
663996b3 MS |
1213 | |
1214 | </refentry> |