projects / thirdparty / systemd.git / blame
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1 | <?xml version='1.0'?> <!--*-nxml-*--> |
| 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" | |
| 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> | |
| 4 | ||
| 5 | <!-- | |
| 6 | This file is part of systemd. | |
| 7 | ||
| 8 | Copyright 2010 Lennart Poettering | |
| 9 | ||
| 10 | systemd is free software; you can redistribute it and/or modify it | |
| 5430f7f2 LP |
11 | under the terms of the GNU Lesser General Public License as published by |
| 12 | the Free Software Foundation; either version 2.1 of the License, or | |
| 9e632bf7 LP |
13 | (at your option) any later version. |
| 14 | ||
| 15 | systemd is distributed in the hope that it will be useful, but | |
| 16 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 5430f7f2 | 18 | Lesser General Public License for more details. |
| 9e632bf7 | 19 | |
| 5430f7f2 | 20 | You should have received a copy of the GNU Lesser General Public License |
| 9e632bf7 LP |
21 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
| 22 | --> | |
| 23 | ||
| dfdebb1b ZJS |
24 | <refentry id="systemd" |
| 25 | xmlns:xi="http://www.w3.org/2001/XInclude"> | |
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26 | |
| 27 | <refentryinfo> | |
| 28 | <title>systemd</title> | |
| 29 | <productname>systemd</productname> | |
| 30 | ||
| 31 | <authorgroup> | |
| 32 | <author> | |
| 33 | <contrib>Developer</contrib> | |
| 34 | <firstname>Lennart</firstname> | |
| 35 | <surname>Poettering</surname> | |
| 36 | <email>lennart@poettering.net</email> | |
| 37 | </author> | |
| 38 | </authorgroup> | |
| 39 | </refentryinfo> | |
| 40 | ||
| 41 | <refmeta> | |
| 42 | <refentrytitle>systemd</refentrytitle> | |
| 160cd5c9 | 43 | <manvolnum>1</manvolnum> |
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44 | </refmeta> |
| 45 | ||
| 46 | <refnamediv> | |
| 47 | <refname>systemd</refname> | |
| 6f6083dc | 48 | <refname>init</refname> |
| 34511ca7 | 49 | <refpurpose>systemd system and service manager</refpurpose> |
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50 | </refnamediv> |
| 51 | ||
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52 | <refsynopsisdiv> |
| 53 | <cmdsynopsis> | |
| 160cd5c9 | 54 | <command>systemd <arg choice="opt" rep="repeat">OPTIONS</arg></command> |
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55 | </cmdsynopsis> |
| 56 | <cmdsynopsis> | |
| 160cd5c9 | 57 | <command>init <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="req">COMMAND</arg></command> |
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58 | </cmdsynopsis> |
| 59 | </refsynopsisdiv> | |
| 60 | ||
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61 | <refsect1> |
| 62 | <title>Description</title> | |
| 63 | ||
| af2d49f7 | 64 | <para>systemd is a system and service manager for |
| 2218198b | 65 | Linux operating systems. When run as first process on |
| af62c704 KS |
66 | boot (as PID 1), it acts as init system that brings |
| 67 | up and maintains userspace services.</para> | |
| 2218198b | 68 | |
| af62c704 | 69 | <para>For compatibility with SysV, if systemd is called |
| 2218198b | 70 | as <command>init</command> and a PID that is not |
| af62c704 | 71 | 1, it will execute <command>telinit</command> and pass |
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72 | all command line arguments unmodified. That means |
| 73 | <command>init</command> and <command>telinit</command> | |
| 74 | are mostly equivalent when invoked from normal login sessions. See | |
| 75 | <citerefentry><refentrytitle>telinit</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
| 76 | for more information.</para> | |
| f3e219a2 | 77 | |
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78 | <para>When run as a system instance, systemd interprets the |
| 79 | configuration file <filename>system.conf</filename> and the | |
| 80 | files in <filename>system.conf.d</filename> directories; when | |
| 81 | run as a user instance, systemd interprets the configuration | |
| 82 | file <filename>user.conf</filename> and the files in | |
| 83 | <filename>user.conf.d</filename> directories. See | |
| 5f9cfd4c | 84 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
| f3e219a2 | 85 | for more information.</para> |
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86 | </refsect1> |
| 87 | ||
| 88 | <refsect1> | |
| 89 | <title>Options</title> | |
| 90 | ||
| 91 | <para>The following options are understood:</para> | |
| 92 | ||
| 93 | <variablelist> | |
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94 | <varlistentry> |
| 95 | <term><option>--test</option></term> | |
| 96 | ||
| 97 | <listitem><para>Determine startup | |
| 98 | sequence, dump it and exit. This is an | |
| 99 | option useful for debugging | |
| 100 | only.</para></listitem> | |
| 101 | </varlistentry> | |
| 102 | <varlistentry> | |
| 103 | <term><option>--dump-configuration-items</option></term> | |
| 104 | ||
| 105 | <listitem><para>Dump understood unit | |
| 106 | configuration items. This outputs a | |
| 107 | terse but complete list of | |
| 108 | configuration items understood in unit | |
| 109 | definition files.</para></listitem> | |
| 110 | </varlistentry> | |
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111 | <varlistentry> |
| 112 | <term><option>--unit=</option></term> | |
| 113 | ||
| 114 | <listitem><para>Set default unit to | |
| 79640424 | 115 | activate on startup. If not specified, |
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116 | defaults to |
| 117 | <filename>default.target</filename>.</para></listitem> | |
| 118 | </varlistentry> | |
| 119 | <varlistentry> | |
| edb9aaa8 | 120 | <term><option>--system</option></term> |
| af2d49f7 | 121 | <term><option>--user</option></term> |
| edb9aaa8 | 122 | |
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123 | <listitem><para>For <option>--system</option>, |
| 124 | tell systemd to run a | |
| 125 | system instance, even if the process ID is | |
| 126 | not 1, i.e. systemd is not run as init process. | |
| 127 | <option>--user</option> does the opposite, | |
| 128 | running a user instance even if the process | |
| 129 | ID is 1. | |
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130 | Normally it should not be necessary to |
| 131 | pass these options, as systemd | |
| 132 | automatically detects the mode it is | |
| 133 | started in. These options are hence of | |
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134 | little use except for debugging. Note |
| 135 | that it is not supported booting and | |
| 136 | maintaining a full system with systemd | |
| 137 | running in <option>--system</option> | |
| 138 | mode, but PID not 1. In practice, | |
| 139 | passing <option>--system</option> explicitly is | |
| 140 | only useful in conjunction with | |
| 141 | <option>--test</option>.</para></listitem> | |
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142 | </varlistentry> |
| 143 | <varlistentry> | |
| f3e219a2 | 144 | <term><option>--dump-core</option></term> |
| 2218198b | 145 | |
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146 | <listitem><para>Dump core on |
| 147 | crash. This switch has no effect when | |
| 148 | run as user | |
| 149 | instance.</para></listitem> | |
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150 | </varlistentry> |
| 151 | <varlistentry> | |
| f3e219a2 | 152 | <term><option>--crash-shell</option></term> |
| 2218198b | 153 | |
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154 | <listitem><para>Run shell on |
| 155 | crash. This switch has no effect when | |
| 156 | run as user | |
| 157 | instance.</para></listitem> | |
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158 | </varlistentry> |
| 159 | <varlistentry> | |
| 160 | <term><option>--confirm-spawn</option></term> | |
| 161 | ||
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162 | <listitem><para>Ask for confirmation |
| 163 | when spawning processes. This switch | |
| 164 | has no effect when run as user | |
| 165 | instance.</para></listitem> | |
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166 | </varlistentry> |
| 167 | <varlistentry> | |
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168 | <term><option>--show-status=</option></term> |
| 169 | ||
| 170 | <listitem><para>Show terse service | |
| 171 | status information while booting. This | |
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172 | switch has no effect when run as user |
| 173 | instance. Takes a boolean argument | |
| 174 | which may be omitted which is | |
| 175 | interpreted as | |
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176 | <option>true</option>.</para></listitem> |
| 177 | </varlistentry> | |
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178 | <varlistentry> |
| 179 | <term><option>--log-target=</option></term> | |
| 180 | ||
| 181 | <listitem><para>Set log | |
| 182 | target. Argument must be one of | |
| 183 | <option>console</option>, | |
| 4cfa2c99 | 184 | <option>journal</option>, |
| f3e219a2 | 185 | <option>kmsg</option>, |
| 4cfa2c99 | 186 | <option>journal-or-kmsg</option>, |
| f3e219a2 | 187 | <option>null</option>.</para></listitem> |
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188 | </varlistentry> |
| 189 | <varlistentry> | |
| 190 | <term><option>--log-level=</option></term> | |
| 191 | ||
| 192 | <listitem><para>Set log level. As | |
| 193 | argument this accepts a numerical log | |
| 5aded369 | 194 | level or the well-known <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
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195 | symbolic names (lowercase): |
| 196 | <option>emerg</option>, | |
| 197 | <option>alert</option>, | |
| 198 | <option>crit</option>, | |
| 199 | <option>err</option>, | |
| 200 | <option>warning</option>, | |
| 201 | <option>notice</option>, | |
| 202 | <option>info</option>, | |
| 203 | <option>debug</option>.</para></listitem> | |
| 204 | </varlistentry> | |
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205 | <varlistentry> |
| 206 | <term><option>--log-color=</option></term> | |
| 207 | ||
| 208 | <listitem><para>Highlight important | |
| 209 | log messages. Argument is a boolean | |
| 79640424 | 210 | value. If the argument is omitted, it |
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211 | defaults to |
| 212 | <option>true</option>.</para></listitem> | |
| 213 | </varlistentry> | |
| 214 | <varlistentry> | |
| 215 | <term><option>--log-location=</option></term> | |
| 216 | ||
| 217 | <listitem><para>Include code location | |
| 218 | in log messages. This is mostly | |
| 219 | relevant for debugging | |
| 220 | purposes. Argument is a boolean | |
| 221 | value. If the argument is omitted | |
| 222 | it defaults to | |
| 223 | <option>true</option>.</para></listitem> | |
| 224 | </varlistentry> | |
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225 | <varlistentry> |
| 226 | <term><option>--default-standard-output=</option></term> | |
| 227 | <term><option>--default-standard-error=</option></term> | |
| 228 | ||
| 229 | <listitem><para>Sets the default | |
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230 | output or error output for all |
| 231 | services and sockets, respectively. That is, controls | |
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232 | the default for |
| 233 | <option>StandardOutput=</option> | |
| 16dad32e | 234 | and <option>StandardError=</option> |
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235 | (see |
| 236 | <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
| 237 | for details). Takes one of | |
| 238 | <option>inherit</option>, | |
| 239 | <option>null</option>, | |
| 240 | <option>tty</option>, | |
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241 | <option>journal</option>, |
| 242 | <option>journal+console</option>, | |
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243 | <option>syslog</option>, |
| 244 | <option>syslog+console</option>, | |
| 245 | <option>kmsg</option>, | |
| 756a8d17 | 246 | <option>kmsg+console</option>. If the |
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247 | argument is omitted |
| 248 | <option>--default-standard-output=</option> | |
| 4cfa2c99 | 249 | defaults to <option>journal</option> |
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250 | and |
| 251 | <option>--default-standard-error=</option> | |
| 252 | to | |
| 934da035 | 253 | <option>inherit</option>.</para></listitem> |
| 0a494f1f | 254 | </varlistentry> |
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255 | |
| 256 | <xi:include href="standard-options.xml" xpointer="help" /> | |
| 257 | <xi:include href="standard-options.xml" xpointer="version" /> | |
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258 | </variablelist> |
| 259 | </refsect1> | |
| 260 | ||
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261 | <refsect1> |
| 262 | <title>Concepts</title> | |
| 263 | ||
| 264 | <para>systemd provides a dependency system between | |
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265 | various entities called "units" of 12 different |
| 266 | types. Units encapsulate various objects that are | |
| 267 | relevant for system boot-up and maintenance. The | |
| 268 | majority of units are configured in unit configuration | |
| 269 | files, whose syntax and basic set of options is | |
| 270 | described in | |
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271 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| 272 | however some are created automatically from other | |
| 1ec96668 | 273 | configuration, dynamically from system state or |
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274 | programmatically at runtime. Units may be "active" |
| 275 | (meaning started, bound, plugged in, ..., depending on | |
| 276 | the unit type, see below), or "inactive" (meaning | |
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277 | stopped, unbound, unplugged, ...), as well as in the |
| 278 | process of being activated or deactivated, | |
| 279 | i.e. between the two states (these states are called | |
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280 | "activating", "deactivating"). A special "failed" |
| 281 | state is available as well, which is very similar to | |
| 282 | "inactive" and is entered when the service failed in | |
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283 | some way (process returned error code on exit, or |
| 284 | crashed, or an operation timed out). If this state is | |
| fbce1139 | 285 | entered, the cause will be logged, for later |
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286 | reference. Note that the various unit types may have a |
| 287 | number of additional substates, which are mapped to | |
| 288 | the five generalized unit states described | |
| 289 | here.</para> | |
| 290 | ||
| 291 | <para>The following unit types are available:</para> | |
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292 | |
| 293 | <orderedlist> | |
| 1ec96668 | 294 | <listitem><para>Service units, which start and control |
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295 | daemons and the processes they consist of. For |
| 296 | details see | |
| 297 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 298 | ||
| 299 | <listitem><para>Socket units, which | |
| 300 | encapsulate local IPC or network sockets in | |
| 301 | the system, useful for socket-based | |
| 302 | activation. For details about socket units see | |
| 303 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
| 304 | for details on socket-based activation and | |
| 305 | other forms of activation, see | |
| 306 | <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para></listitem> | |
| 307 | ||
| 308 | <listitem><para>Target units are useful to | |
| 309 | group units, or provide well-known | |
| 310 | synchronization points during boot-up, see | |
| 311 | <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 312 | ||
| 313 | <listitem><para>Device units expose kernel | |
| 314 | devices in systemd and may be used to | |
| 315 | implement device-based activation. For details | |
| 316 | see | |
| 317 | <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 318 | ||
| 319 | <listitem><para>Mount units control mount | |
| 320 | points in the file system, for details see | |
| 321 | <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 322 | ||
| 323 | <listitem><para>Automount units provide | |
| 324 | automount capabilities, for on-demand mounting | |
| 325 | of file systems as well as parallelized | |
| 326 | boot-up. See | |
| 327 | <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 328 | ||
| 329 | <listitem><para>Snapshot units can be used to | |
| 330 | temporarily save the state of the set of | |
| 331 | systemd units, which later may be restored by | |
| 332 | activating the saved snapshot unit. For more | |
| 333 | information see | |
| 7461d1b7 | 334 | <citerefentry><refentrytitle>systemd.snapshot</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
| 99ffae46 LP |
335 | |
| 336 | <listitem><para>Timer units are useful for | |
| 337 | triggering activation of other units based on | |
| 338 | timers. You may find details in | |
| 339 | <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 340 | ||
| 341 | <listitem><para>Swap units are very similar to | |
| f8553ccb | 342 | mount units and encapsulate memory swap |
| 99ffae46 | 343 | partitions or files of the operating |
| f8553ccb | 344 | system. They are described in <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
| 99ffae46 LP |
345 | |
| 346 | <listitem><para>Path units may be used | |
| dccb2600 | 347 | to activate other services when file system |
| 99ffae46 LP |
348 | objects change or are modified. See |
| 349 | <citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 350 | ||
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351 | <listitem><para>Slice units may be used to |
| 352 | group units which manage system processes | |
| 353 | (such as service and scope units) in a | |
| 5eec7de6 | 354 | hierarchical tree for resource management |
| 1ec96668 LP |
355 | purposes. See |
| 356 | <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 357 | ||
| 358 | <listitem><para>Scope units are similar to | |
| 359 | service units, but manage foreign processes | |
| 360 | instead of starting them as well. See | |
| 361 | <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 362 | ||
| 99ffae46 LP |
363 | </orderedlist> |
| 364 | ||
| 365 | <para>Units are named as their configuration | |
| 366 | files. Some units have special semantics. A detailed | |
| f8553ccb | 367 | list is available in |
| 99ffae46 LP |
368 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> |
| 369 | ||
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370 | <para>systemd knows various kinds of dependencies, |
| 371 | including positive and negative requirement | |
| 372 | dependencies (i.e. <varname>Requires=</varname> and | |
| 373 | <varname>Conflicts=</varname>) as well as ordering | |
| 374 | dependencies (<varname>After=</varname> and | |
| 375 | <varname>Before=</varname>). NB: ordering and | |
| 376 | requirement dependencies are orthogonal. If only a | |
| 377 | requirement dependency exists between two units | |
| 378 | (e.g. <filename>foo.service</filename> requires | |
| 379 | <filename>bar.service</filename>), but no ordering | |
| 380 | dependency (e.g. <filename>foo.service</filename> | |
| 381 | after <filename>bar.service</filename>) and both are | |
| 382 | requested to start, they will be started in | |
| 383 | parallel. It is a common pattern that both requirement | |
| 384 | and ordering dependencies are placed between two | |
| 385 | units. Also note that the majority of dependencies are | |
| 386 | implicitly created and maintained by systemd. In most | |
| 73e231ab | 387 | cases, it should be unnecessary to declare additional |
| b9975629 LP |
388 | dependencies manually, however it is possible to do |
| 389 | this.</para> | |
| 390 | ||
| 391 | <para>Application programs and units (via | |
| f8553ccb | 392 | dependencies) may request state changes of units. In |
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393 | systemd, these requests are encapsulated as 'jobs' and |
| 394 | maintained in a job queue. Jobs may succeed or can | |
| 395 | fail, their execution is ordered based on the ordering | |
| 396 | dependencies of the units they have been scheduled | |
| 397 | for.</para> | |
| 398 | ||
| 99ffae46 | 399 | <para>On boot systemd activates the target unit |
| dccb2600 | 400 | <filename>default.target</filename> whose job is to |
| 99ffae46 LP |
401 | activate on-boot services and other on-boot units by |
| 402 | pulling them in via dependencies. Usually the unit | |
| 403 | name is just an alias (symlink) for either | |
| 404 | <filename>graphical.target</filename> (for | |
| 405 | fully-featured boots into the UI) or | |
| 406 | <filename>multi-user.target</filename> (for limited | |
| 407 | console-only boots for use in embedded or server | |
| 408 | environments, or similar; a subset of | |
| 79640424 | 409 | graphical.target). However, it is at the discretion of |
| 99ffae46 LP |
410 | the administrator to configure it as an alias to any |
| 411 | other target unit. See | |
| 412 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
| 413 | for details about these target units.</para> | |
| 414 | ||
| dccb2600 | 415 | <para>Processes systemd spawns are placed in |
| 59a3e1bc LP |
416 | individual Linux control groups named after the unit |
| 417 | which they belong to in the private systemd | |
| 418 | hierarchy. (see <ulink | |
| 6ed80a4e | 419 | url="https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink> |
| 59a3e1bc LP |
420 | for more information about control groups, or short |
| 421 | "cgroups"). systemd uses this to effectively keep | |
| 422 | track of processes. Control group information is | |
| 423 | maintained in the kernel, and is accessible via the | |
| 424 | file system hierarchy (beneath | |
| 77d5f105 | 425 | <filename>/sys/fs/cgroup/systemd/</filename>), or in tools |
| 59a3e1bc | 426 | such as |
| 5aded369 | 427 | <citerefentry project='man-pages'><refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| 59a3e1bc LP |
428 | (<command>ps xawf -eo pid,user,cgroup,args</command> |
| 429 | is particularly useful to list all processes and the | |
| 430 | systemd units they belong to.).</para> | |
| 431 | ||
| 432 | <para>systemd is compatible with the SysV init system | |
| 433 | to a large degree: SysV init scripts are supported and | |
| 434 | simply read as an alternative (though limited) | |
| 435 | configuration file format. The SysV | |
| 436 | <filename>/dev/initctl</filename> interface is | |
| dccb2600 OÇ |
437 | provided, and compatibility implementations of the |
| 438 | various SysV client tools are available. In addition to | |
| 439 | that, various established Unix functionality such as | |
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440 | <filename>/etc/fstab</filename> or the |
| 441 | <filename>utmp</filename> database are | |
| 442 | supported.</para> | |
| 443 | ||
| 444 | <para>systemd has a minimal transaction system: if a | |
| 445 | unit is requested to start up or shut down it will add | |
| 446 | it and all its dependencies to a temporary | |
| 447 | transaction. Then, it will verify if the transaction | |
| 448 | is consistent (i.e. whether the ordering of all units | |
| 449 | is cycle-free). If it is not, systemd will try to fix | |
| 450 | it up, and removes non-essential jobs from the | |
| 451 | transaction that might remove the loop. Also, systemd | |
| 452 | tries to suppress non-essential jobs in the | |
| 453 | transaction that would stop a running service. Finally | |
| 454 | it is checked whether the jobs of the transaction | |
| 455 | contradict jobs that have already been queued, and | |
| 456 | optionally the transaction is aborted then. If all | |
| 457 | worked out and the transaction is consistent and | |
| 458 | minimized in its impact it is merged with all already | |
| 459 | outstanding jobs and added to the run | |
| 460 | queue. Effectively this means that before executing a | |
| 461 | requested operation, systemd will verify that it makes | |
| 462 | sense, fixing it if possible, and only failing if it | |
| 463 | really cannot work.</para> | |
| 464 | ||
| 465 | <para>Systemd contains native implementations of | |
| 466 | various tasks that need to be executed as part of the | |
| e9dd9f95 | 467 | boot process. For example, it sets the hostname or |
| 59a3e1bc LP |
468 | configures the loopback network device. It also sets |
| 469 | up and mounts various API file systems, such as | |
| 470 | <filename>/sys</filename> or | |
| 471 | <filename>/proc</filename>.</para> | |
| 472 | ||
| 99ffae46 | 473 | <para>For more information about the concepts and |
| b040723e | 474 | ideas behind systemd, please refer to the <ulink |
| 99ffae46 | 475 | url="http://0pointer.de/blog/projects/systemd.html">Original |
| 59a3e1bc | 476 | Design Document</ulink>.</para> |
| b9aea954 LP |
477 | |
| 478 | <para>Note that some but not all interfaces provided | |
| 479 | by systemd are covered by the <ulink | |
| 480 | url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface | |
| 481 | Stability Promise</ulink>.</para> | |
| 059b37cc LP |
482 | |
| 483 | <para>Units may be generated dynamically at boot and | |
| 484 | system manager reload time, for example based on other | |
| 485 | configuration files or parameters passed on the kernel | |
| 486 | command line. For details see the <ulink | |
| 487 | url="http://www.freedesktop.org/wiki/Software/systemd/Generators">Generators | |
| 488 | Specification</ulink>.</para> | |
| 99800333 LP |
489 | |
| 490 | <para>Systems which invoke systemd in a container | |
| 16dad32e | 491 | or initrd environment should implement the |
| 99800333 LP |
492 | <ulink |
| 493 | url="http://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container | |
| 16dad32e | 494 | Interface</ulink> or <ulink |
| 99800333 | 495 | url="http://www.freedesktop.org/wiki/Software/systemd/InitrdInterface">initrd |
| 16dad32e | 496 | Interface</ulink> specifications, respectively.</para> |
| 99ffae46 LP |
497 | </refsect1> |
| 498 | ||
| 160cd5c9 LP |
499 | <refsect1> |
| 500 | <title>Directories</title> | |
| 7874bcd6 | 501 | |
| 19adb8a3 | 502 | <variablelist> |
| 7874bcd6 LP |
503 | <varlistentry> |
| 504 | <term>System unit directories</term> | |
| 505 | ||
| 506 | <listitem><para>The systemd system | |
| 507 | manager reads unit configuration from | |
| 508 | various directories. Packages that | |
| 509 | want to install unit files shall place | |
| 510 | them in the directory returned by | |
| 511 | <command>pkg-config systemd | |
| 512 | --variable=systemdsystemunitdir</command>. Other | |
| 513 | directories checked are | |
| d636fa3d | 514 | <filename>/usr/local/lib/systemd/system</filename> |
| 7874bcd6 | 515 | and |
| d636fa3d | 516 | <filename>/usr/lib/systemd/system</filename>. User |
| 7874bcd6 LP |
517 | configuration always takes |
| 518 | precedence. <command>pkg-config | |
| 519 | systemd | |
| 520 | --variable=systemdsystemconfdir</command> | |
| 521 | returns the path of the system | |
| 522 | configuration directory. Packages | |
| ee5762e3 LP |
523 | should alter the content of these |
| 524 | directories only with the | |
| 525 | <command>enable</command> and | |
| 526 | <command>disable</command> commands of | |
| 527 | the | |
| 528 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
| 13219b7f ZJS |
529 | tool. Full list of directories is provided in |
| 530 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. | |
| 531 | </para></listitem> | |
| 7874bcd6 LP |
532 | </varlistentry> |
| 533 | </variablelist> | |
| 534 | ||
| 535 | <variablelist> | |
| 536 | <varlistentry> | |
| af2d49f7 | 537 | <term>User unit directories</term> |
| 7874bcd6 LP |
538 | |
| 539 | <listitem><para>Similar rules apply | |
| af2d49f7 | 540 | for the user unit |
| 7874bcd6 LP |
541 | directories. However, here the <ulink |
| 542 | url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG | |
| 543 | Base Directory specification</ulink> | |
| 544 | is followed to find | |
| 545 | units. Applications should place their | |
| 546 | unit files in the directory returned | |
| 547 | by <command>pkg-config systemd | |
| af2d49f7 | 548 | --variable=systemduserunitdir</command>. Global |
| ee5762e3 LP |
549 | configuration is done in the directory |
| 550 | reported by <command>pkg-config | |
| 551 | systemd | |
| af2d49f7 | 552 | --variable=systemduserconfdir</command>. The |
| ee5762e3 LP |
553 | <command>enable</command> and |
| 554 | <command>disable</command> commands of | |
| 555 | the | |
| 556 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
| 7874bcd6 LP |
557 | tool can handle both global (i.e. for |
| 558 | all users) and private (for one user) | |
| 559 | enabling/disabling of | |
| 13219b7f ZJS |
560 | units. Full list of directories is provided in |
| 561 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. | |
| 562 | </para></listitem> | |
| 7874bcd6 LP |
563 | </varlistentry> |
| 564 | </variablelist> | |
| 565 | ||
| 566 | <variablelist> | |
| 567 | <varlistentry> | |
| 568 | <term>SysV init scripts directory</term> | |
| 569 | ||
| 570 | <listitem><para>The location of the | |
| 571 | SysV init script directory varies | |
| 572 | between distributions. If systemd | |
| 573 | cannot find a native unit file for a | |
| af62c704 | 574 | requested service, it will look for a |
| 7874bcd6 LP |
575 | SysV init script of the same name |
| 576 | (with the | |
| 577 | <filename>.service</filename> suffix | |
| 578 | removed).</para></listitem> | |
| 579 | </varlistentry> | |
| 580 | </variablelist> | |
| 581 | ||
| 582 | <variablelist> | |
| 583 | <varlistentry> | |
| 584 | <term>SysV runlevel link farm directory</term> | |
| 585 | ||
| 586 | <listitem><para>The location of the | |
| 587 | SysV runlevel link farm directory | |
| 588 | varies between distributions. systemd | |
| 589 | will take the link farm into account | |
| 590 | when figuring out whether a service | |
| 591 | shall be enabled. Note that a service | |
| 592 | unit with a native unit configuration | |
| edb9aaa8 | 593 | file cannot be started by activating it |
| 7874bcd6 LP |
594 | in the SysV runlevel link |
| 595 | farm.</para></listitem> | |
| 596 | </varlistentry> | |
| 597 | </variablelist> | |
| 160cd5c9 LP |
598 | </refsect1> |
| 599 | ||
| 600 | <refsect1> | |
| 7874bcd6 | 601 | <title>Signals</title> |
| 160cd5c9 LP |
602 | |
| 603 | <variablelist> | |
| 604 | <varlistentry> | |
| 74d00578 | 605 | <term><constant>SIGTERM</constant></term> |
| 7874bcd6 LP |
606 | |
| 607 | <listitem><para>Upon receiving this | |
| 608 | signal the systemd system manager | |
| 609 | serializes its state, reexecutes | |
| 610 | itself and deserializes the saved | |
| 611 | state again. This is mostly equivalent | |
| 612 | to <command>systemctl | |
| 613 | daemon-reexec</command>.</para> | |
| 614 | ||
| af2d49f7 | 615 | <para>systemd user managers will |
| 7874bcd6 LP |
616 | start the |
| 617 | <filename>exit.target</filename> unit | |
| 618 | when this signal is received. This is | |
| 619 | mostly equivalent to | |
| af2d49f7 | 620 | <command>systemctl --user start |
| 7874bcd6 LP |
621 | exit.target</command>.</para></listitem> |
| 622 | </varlistentry> | |
| 623 | ||
| 624 | <varlistentry> | |
| 74d00578 | 625 | <term><constant>SIGINT</constant></term> |
| 7874bcd6 LP |
626 | |
| 627 | <listitem><para>Upon receiving this | |
| 628 | signal the systemd system manager will | |
| 629 | start the | |
| 630 | <filename>ctrl-alt-del.target</filename> unit. This | |
| 631 | is mostly equivalent to | |
| 632 | <command>systemctl start | |
| 633 | ctl-alt-del.target</command>.</para> | |
| 634 | ||
| af2d49f7 | 635 | <para>systemd user managers |
| 7874bcd6 | 636 | treat this signal the same way as |
| 05cc7267 | 637 | <constant>SIGTERM</constant>.</para></listitem> |
| 7874bcd6 LP |
638 | </varlistentry> |
| 639 | ||
| 640 | <varlistentry> | |
| 74d00578 | 641 | <term><constant>SIGWINCH</constant></term> |
| 7874bcd6 LP |
642 | |
| 643 | <listitem><para>When this signal is | |
| 644 | received the systemd system manager | |
| 645 | will start the | |
| 646 | <filename>kbrequest.target</filename> | |
| 647 | unit. This is mostly equivalent to | |
| 648 | <command>systemctl start | |
| 649 | kbrequest.target</command>.</para> | |
| 650 | ||
| 651 | <para>This signal is ignored by | |
| af2d49f7 | 652 | systemd user |
| 7874bcd6 LP |
653 | managers.</para></listitem> |
| 654 | </varlistentry> | |
| 655 | ||
| 656 | <varlistentry> | |
| 74d00578 | 657 | <term><constant>SIGPWR</constant></term> |
| 7874bcd6 LP |
658 | |
| 659 | <listitem><para>When this signal is | |
| 660 | received the systemd manager | |
| 661 | will start the | |
| 662 | <filename>sigpwr.target</filename> | |
| 663 | unit. This is mostly equivalent to | |
| 664 | <command>systemctl start | |
| 665 | sigpwr.target</command>.</para></listitem> | |
| 666 | </varlistentry> | |
| 667 | ||
| 668 | <varlistentry> | |
| 74d00578 | 669 | <term><constant>SIGUSR1</constant></term> |
| 7874bcd6 LP |
670 | |
| 671 | <listitem><para>When this signal is | |
| 672 | received the systemd manager will try | |
| 673 | to reconnect to the D-Bus | |
| 674 | bus.</para></listitem> | |
| 675 | </varlistentry> | |
| 676 | ||
| 677 | <varlistentry> | |
| 74d00578 | 678 | <term><constant>SIGUSR2</constant></term> |
| 7874bcd6 LP |
679 | |
| 680 | <listitem><para>When this signal is | |
| 681 | received the systemd manager will log | |
| 682 | its complete state in human readable | |
| 683 | form. The data logged is the same as | |
| 030512b2 | 684 | printed by <command>systemd-analyze |
| 7874bcd6 LP |
685 | dump</command>.</para></listitem> |
| 686 | </varlistentry> | |
| 687 | ||
| 688 | <varlistentry> | |
| 74d00578 | 689 | <term><constant>SIGHUP</constant></term> |
| 7874bcd6 LP |
690 | |
| 691 | <listitem><para>Reloads the complete | |
| 692 | daemon configuration. This is mostly | |
| 693 | equivalent to <command>systemctl | |
| 694 | daemon-reload</command>.</para></listitem> | |
| 695 | </varlistentry> | |
| 696 | ||
| 697 | <varlistentry> | |
| 74d00578 | 698 | <term><constant>SIGRTMIN+0</constant></term> |
| 7874bcd6 LP |
699 | |
| 700 | <listitem><para>Enters default mode, starts the | |
| 701 | <filename>default.target</filename> | |
| 702 | unit. This is mostly equivalent to | |
| 703 | <command>systemctl start | |
| 704 | default.target</command>.</para></listitem> | |
| 705 | </varlistentry> | |
| 706 | ||
| 707 | <varlistentry> | |
| 74d00578 | 708 | <term><constant>SIGRTMIN+1</constant></term> |
| 7874bcd6 LP |
709 | |
| 710 | <listitem><para>Enters rescue mode, | |
| 711 | starts the | |
| 712 | <filename>rescue.target</filename> | |
| 713 | unit. This is mostly equivalent to | |
| 714 | <command>systemctl isolate | |
| 715 | rescue.target</command>.</para></listitem> | |
| 716 | </varlistentry> | |
| 160cd5c9 | 717 | |
| 7874bcd6 | 718 | <varlistentry> |
| 74d00578 | 719 | <term><constant>SIGRTMIN+2</constant></term> |
| 7874bcd6 LP |
720 | |
| 721 | <listitem><para>Enters emergency mode, | |
| 722 | starts the | |
| 723 | <filename>emergency.service</filename> | |
| 724 | unit. This is mostly equivalent to | |
| 725 | <command>systemctl isolate | |
| 726 | emergency.service</command>.</para></listitem> | |
| 727 | </varlistentry> | |
| 728 | ||
| 729 | <varlistentry> | |
| 74d00578 | 730 | <term><constant>SIGRTMIN+3</constant></term> |
| 7874bcd6 LP |
731 | |
| 732 | <listitem><para>Halts the machine, | |
| 733 | starts the | |
| 734 | <filename>halt.target</filename> | |
| 735 | unit. This is mostly equivalent to | |
| 736 | <command>systemctl start | |
| 737 | halt.target</command>.</para></listitem> | |
| 738 | </varlistentry> | |
| 739 | ||
| 740 | <varlistentry> | |
| 74d00578 | 741 | <term><constant>SIGRTMIN+4</constant></term> |
| 7874bcd6 LP |
742 | |
| 743 | <listitem><para>Powers off the machine, | |
| 744 | starts the | |
| 745 | <filename>poweroff.target</filename> | |
| 746 | unit. This is mostly equivalent to | |
| 747 | <command>systemctl start | |
| 748 | poweroff.target</command>.</para></listitem> | |
| 749 | </varlistentry> | |
| 750 | ||
| 751 | <varlistentry> | |
| 74d00578 | 752 | <term><constant>SIGRTMIN+5</constant></term> |
| 7874bcd6 LP |
753 | |
| 754 | <listitem><para>Reboots the machine, | |
| 755 | starts the | |
| 756 | <filename>reboot.target</filename> | |
| 757 | unit. This is mostly equivalent to | |
| 758 | <command>systemctl start | |
| 759 | reboot.target</command>.</para></listitem> | |
| 160cd5c9 | 760 | </varlistentry> |
| 0658666b LP |
761 | |
| 762 | <varlistentry> | |
| 74d00578 | 763 | <term><constant>SIGRTMIN+6</constant></term> |
| 0658666b LP |
764 | |
| 765 | <listitem><para>Reboots the machine via kexec, | |
| 766 | starts the | |
| 767 | <filename>kexec.target</filename> | |
| 768 | unit. This is mostly equivalent to | |
| 769 | <command>systemctl start | |
| 770 | kexec.target</command>.</para></listitem> | |
| 771 | </varlistentry> | |
| 772 | ||
| 773 | <varlistentry> | |
| 74d00578 | 774 | <term><constant>SIGRTMIN+13</constant></term> |
| 0658666b LP |
775 | |
| 776 | <listitem><para>Immediately halts the machine.</para></listitem> | |
| 777 | </varlistentry> | |
| 778 | ||
| 779 | <varlistentry> | |
| 74d00578 | 780 | <term><constant>SIGRTMIN+14</constant></term> |
| 0658666b LP |
781 | |
| 782 | <listitem><para>Immediately powers off the machine.</para></listitem> | |
| 783 | </varlistentry> | |
| 784 | ||
| 785 | <varlistentry> | |
| 74d00578 | 786 | <term><constant>SIGRTMIN+15</constant></term> |
| 0658666b LP |
787 | |
| 788 | <listitem><para>Immediately reboots the machine.</para></listitem> | |
| 789 | </varlistentry> | |
| 790 | ||
| 791 | <varlistentry> | |
| 74d00578 | 792 | <term><constant>SIGRTMIN+16</constant></term> |
| 0658666b LP |
793 | |
| 794 | <listitem><para>Immediately reboots the machine with kexec.</para></listitem> | |
| 795 | </varlistentry> | |
| 796 | ||
| 797 | <varlistentry> | |
| 74d00578 | 798 | <term><constant>SIGRTMIN+20</constant></term> |
| 0658666b LP |
799 | |
| 800 | <listitem><para>Enables display of | |
| 801 | status messages on the console, as | |
| 802 | controlled via | |
| 803 | <varname>systemd.show_status=1</varname> | |
| 804 | on the kernel command | |
| 805 | line.</para></listitem> | |
| 806 | </varlistentry> | |
| 807 | ||
| 808 | <varlistentry> | |
| 74d00578 | 809 | <term><constant>SIGRTMIN+21</constant></term> |
| 0658666b LP |
810 | |
| 811 | <listitem><para>Disables display of | |
| 812 | status messages on the console, as | |
| 813 | controlled via | |
| 814 | <varname>systemd.show_status=0</varname> | |
| 815 | on the kernel command | |
| 816 | line.</para></listitem> | |
| 817 | </varlistentry> | |
| 253ee27a LP |
818 | |
| 819 | <varlistentry> | |
| 74d00578 ZJS |
820 | <term><constant>SIGRTMIN+22</constant></term> |
| 821 | <term><constant>SIGRTMIN+23</constant></term> | |
| 253ee27a LP |
822 | |
| 823 | <listitem><para>Sets the log level to | |
| 824 | <literal>debug</literal> | |
| 16dad32e | 825 | (or <literal>info</literal> on |
| 74d00578 | 826 | <constant>SIGRTMIN+23</constant>), as |
| 253ee27a LP |
827 | controlled via |
| 828 | <varname>systemd.log_level=debug</varname> | |
| 16dad32e | 829 | (or <varname>systemd.log_level=info</varname> |
| 74d00578 | 830 | on <constant>SIGRTMIN+23</constant>) on |
| 253ee27a LP |
831 | the kernel command |
| 832 | line.</para></listitem> | |
| 833 | </varlistentry> | |
| 834 | ||
| 600b704e | 835 | <varlistentry> |
| 74d00578 | 836 | <term><constant>SIGRTMIN+24</constant></term> |
| 600b704e LP |
837 | |
| 838 | <listitem><para>Immediately exits the | |
| 839 | manager (only available for --user | |
| 840 | instances).</para></listitem> | |
| 841 | </varlistentry> | |
| 842 | ||
| 253ee27a | 843 | <varlistentry> |
| 74d00578 ZJS |
844 | <term><constant>SIGRTMIN+26</constant></term> |
| 845 | <term><constant>SIGRTMIN+27</constant></term> | |
| 846 | <term><constant>SIGRTMIN+28</constant></term> | |
| 253ee27a LP |
847 | |
| 848 | <listitem><para>Sets the log level to | |
| ee0e998e LP |
849 | <literal>journal-or-kmsg</literal> (or |
| 850 | <literal>console</literal> on | |
| 74d00578 | 851 | <constant>SIGRTMIN+27</constant>, |
| 16dad32e | 852 | <literal>kmsg</literal> on |
| ee0e998e | 853 | <constant>SIGRTMIN+28</constant>), as |
| 253ee27a | 854 | controlled via |
| 4cfa2c99 | 855 | <varname>systemd.log_target=journal-or-kmsg</varname> |
| ee0e998e LP |
856 | (or |
| 857 | <varname>systemd.log_target=console</varname> | |
| 858 | on <constant>SIGRTMIN+27</constant> or | |
| 16dad32e | 859 | <varname>systemd.log_target=kmsg</varname> |
| ee0e998e LP |
860 | on <constant>SIGRTMIN+28</constant>) |
| 861 | on the kernel command | |
| 253ee27a LP |
862 | line.</para></listitem> |
| 863 | </varlistentry> | |
| 160cd5c9 LP |
864 | </variablelist> |
| 865 | </refsect1> | |
| 866 | ||
| 7874bcd6 LP |
867 | <refsect1> |
| 868 | <title>Environment</title> | |
| 869 | ||
| 08177c85 | 870 | <variablelist class='environment-variables'> |
| 7874bcd6 LP |
871 | <varlistentry> |
| 872 | <term><varname>$SYSTEMD_LOG_LEVEL</varname></term> | |
| 873 | <listitem><para>systemd reads the | |
| 874 | log level from this environment | |
| 436c44a5 | 875 | variable. This can be overridden with |
| 7874bcd6 LP |
876 | <option>--log-level=</option>.</para></listitem> |
| 877 | </varlistentry> | |
| 878 | ||
| 879 | <varlistentry> | |
| 880 | <term><varname>$SYSTEMD_LOG_TARGET</varname></term> | |
| 881 | <listitem><para>systemd reads the | |
| 882 | log target from this environment | |
| 436c44a5 | 883 | variable. This can be overridden with |
| 7874bcd6 LP |
884 | <option>--log-target=</option>.</para></listitem> |
| 885 | </varlistentry> | |
| 886 | ||
| 887 | <varlistentry> | |
| 888 | <term><varname>$SYSTEMD_LOG_COLOR</varname></term> | |
| 889 | <listitem><para>Controls whether | |
| 890 | systemd highlights important log | |
| 436c44a5 | 891 | messages. This can be overridden with |
| 7874bcd6 LP |
892 | <option>--log-color=</option>.</para></listitem> |
| 893 | </varlistentry> | |
| 894 | ||
| 895 | <varlistentry> | |
| 896 | <term><varname>$SYSTEMD_LOG_LOCATION</varname></term> | |
| 897 | <listitem><para>Controls whether | |
| 898 | systemd prints the code location along | |
| 899 | with log messages. This can be | |
| 436c44a5 | 900 | overridden with |
| 7874bcd6 LP |
901 | <option>--log-location=</option>.</para></listitem> |
| 902 | </varlistentry> | |
| 903 | ||
| 904 | <varlistentry> | |
| 905 | <term><varname>$XDG_CONFIG_HOME</varname></term> | |
| 906 | <term><varname>$XDG_CONFIG_DIRS</varname></term> | |
| 907 | <term><varname>$XDG_DATA_HOME</varname></term> | |
| 908 | <term><varname>$XDG_DATA_DIRS</varname></term> | |
| 909 | ||
| af2d49f7 | 910 | <listitem><para>The systemd user |
| 7874bcd6 LP |
911 | manager uses these variables in |
| 912 | accordance to the <ulink | |
| 913 | url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG | |
| 914 | Base Directory specification</ulink> | |
| 915 | to find its configuration.</para></listitem> | |
| 916 | </varlistentry> | |
| 917 | ||
| 918 | <varlistentry> | |
| 919 | <term><varname>$SYSTEMD_UNIT_PATH</varname></term> | |
| 920 | ||
| 921 | <listitem><para>Controls where systemd | |
| 922 | looks for unit | |
| 923 | files.</para></listitem> | |
| 924 | </varlistentry> | |
| 925 | ||
| 926 | <varlistentry> | |
| 927 | <term><varname>$SYSTEMD_SYSVINIT_PATH</varname></term> | |
| 928 | ||
| 929 | <listitem><para>Controls where systemd | |
| 930 | looks for SysV init scripts.</para></listitem> | |
| 931 | </varlistentry> | |
| 932 | ||
| 933 | <varlistentry> | |
| 934 | <term><varname>$SYSTEMD_SYSVRCND_PATH</varname></term> | |
| 935 | ||
| 936 | <listitem><para>Controls where systemd | |
| 937 | looks for SysV init script runlevel link | |
| 938 | farms.</para></listitem> | |
| 939 | </varlistentry> | |
| 940 | ||
| 941 | <varlistentry> | |
| 942 | <term><varname>$LISTEN_PID</varname></term> | |
| 943 | <term><varname>$LISTEN_FDS</varname></term> | |
| 944 | ||
| 945 | <listitem><para>Set by systemd for | |
| 946 | supervised processes during | |
| 947 | socket-based activation. See | |
| 948 | <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
| 949 | for more information. | |
| 950 | </para></listitem> | |
| 951 | </varlistentry> | |
| 952 | ||
| 953 | <varlistentry> | |
| 954 | <term><varname>$NOTIFY_SOCKET</varname></term> | |
| 955 | ||
| 956 | <listitem><para>Set by systemd for | |
| 957 | supervised processes for status and | |
| 958 | start-up completion notification. See | |
| 959 | <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
| 960 | for more information. | |
| 961 | </para></listitem> | |
| 962 | </varlistentry> | |
| 963 | </variablelist> | |
| 964 | </refsect1> | |
| 160cd5c9 | 965 | |
| f3e219a2 LP |
966 | <refsect1> |
| 967 | <title>Kernel Command Line</title> | |
| 968 | ||
| 45dc3a04 LP |
969 | <para>When run as system instance systemd parses a |
| 970 | number of kernel command line | |
| 971 | arguments<footnote><para>If run inside a Linux | |
| 972 | container these arguments may be passed as command | |
| 973 | line arguments to systemd itself, next to any of the | |
| 974 | command line options listed in the Options section | |
| 975 | above. If run outside of Linux containers, these | |
| 976 | arguments are parsed from | |
| 977 | <filename>/proc/cmdline</filename> | |
| 978 | instead.</para></footnote>:</para> | |
| f3e219a2 | 979 | |
| ccc9a4f9 | 980 | <variablelist class='kernel-commandline-options'> |
| f3e219a2 LP |
981 | <varlistentry> |
| 982 | <term><varname>systemd.unit=</varname></term> | |
| c66e7bc7 | 983 | <term><varname>rd.systemd.unit=</varname></term> |
| f3e219a2 LP |
984 | |
| 985 | <listitem><para>Overrides the unit to | |
| 986 | activate on boot. Defaults to | |
| 987 | <filename>default.target</filename>. This | |
| 988 | may be used to temporarily boot into a | |
| 989 | different boot unit, for example | |
| 990 | <filename>rescue.target</filename> or | |
| 991 | <filename>emergency.service</filename>. See | |
| 992 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
| c66e7bc7 LP |
993 | for details about these units. The |
| 994 | option prefixed with | |
| bb31a4ac | 995 | <literal>rd.</literal> is honored |
| c66e7bc7 | 996 | only in the initial RAM disk (initrd), |
| 6b4991cf | 997 | while the one that is not prefixed only |
| c66e7bc7 | 998 | in the main system.</para></listitem> |
| f3e219a2 LP |
999 | </varlistentry> |
| 1000 | ||
| f3e219a2 LP |
1001 | <varlistentry> |
| 1002 | <term><varname>systemd.dump_core=</varname></term> | |
| 1003 | ||
| 1004 | <listitem><para>Takes a boolean | |
| 79640424 | 1005 | argument. If <option>true</option>, |
| f3e219a2 | 1006 | systemd dumps core when it |
| 79640424 | 1007 | crashes. Otherwise, no core dump is |
| f3e219a2 LP |
1008 | created. Defaults to |
| 1009 | <option>true</option>.</para></listitem> | |
| 1010 | </varlistentry> | |
| 1011 | ||
| 1012 | <varlistentry> | |
| 1013 | <term><varname>systemd.crash_shell=</varname></term> | |
| 1014 | ||
| 1015 | <listitem><para>Takes a boolean | |
| 79640424 | 1016 | argument. If <option>true</option>, |
| f3e219a2 | 1017 | systemd spawns a shell when it |
| 79640424 | 1018 | crashes. Otherwise, no shell is |
| f8553ccb | 1019 | spawned. Defaults to |
| f3e219a2 LP |
1020 | <option>false</option>, for security |
| 1021 | reasons, as the shell is not protected | |
| 1022 | by any password | |
| 1023 | authentication.</para></listitem> | |
| 1024 | </varlistentry> | |
| 1025 | ||
| 1026 | <varlistentry> | |
| 1027 | <term><varname>systemd.crash_chvt=</varname></term> | |
| 1028 | ||
| 1029 | <listitem><para>Takes an integer | |
| 1030 | argument. If positive systemd | |
| 1031 | activates the specified virtual | |
| 1032 | terminal when it crashes. Defaults to | |
| 74d00578 | 1033 | <constant>-1</constant>.</para></listitem> |
| f3e219a2 LP |
1034 | </varlistentry> |
| 1035 | ||
| 69dd2852 LP |
1036 | <varlistentry> |
| 1037 | <term><varname>systemd.confirm_spawn=</varname></term> | |
| 1038 | ||
| 1039 | <listitem><para>Takes a boolean | |
| 79640424 | 1040 | argument. If <option>true</option>, |
| 69dd2852 LP |
1041 | asks for confirmation when spawning |
| 1042 | processes. Defaults to | |
| 1043 | <option>false</option>.</para></listitem> | |
| 1044 | </varlistentry> | |
| 1045 | ||
| f3e219a2 LP |
1046 | <varlistentry> |
| 1047 | <term><varname>systemd.show_status=</varname></term> | |
| 1048 | ||
| 1049 | <listitem><para>Takes a boolean | |
| d450b6f2 ZJS |
1050 | argument or the constant |
| 1051 | <constant>auto</constant>. If | |
| 1052 | <option>true</option>, shows terse | |
| 1053 | service status updates on the console | |
| 1054 | during bootup. | |
| 1055 | <constant>auto</constant> behaves like | |
| 1056 | <option>false</option> until a service | |
| 1057 | fails or there is a significant delay | |
| 1058 | in boot. Defaults to | |
| c66e7bc7 LP |
1059 | <option>true</option>, unless |
| 1060 | <option>quiet</option> is passed as | |
| 1061 | kernel command line option in which | |
| 1062 | case it defaults to | |
| d450b6f2 | 1063 | <constant>auto</constant>.</para></listitem> |
| f3e219a2 LP |
1064 | </varlistentry> |
| 1065 | ||
| 69dd2852 LP |
1066 | <varlistentry> |
| 1067 | <term><varname>systemd.log_target=</varname></term> | |
| 1068 | <term><varname>systemd.log_level=</varname></term> | |
| 1069 | <term><varname>systemd.log_color=</varname></term> | |
| 1070 | <term><varname>systemd.log_location=</varname></term> | |
| 1071 | ||
| 1072 | <listitem><para>Controls log output, | |
| 1073 | with the same effect as the | |
| 1074 | <varname>$SYSTEMD_LOG_TARGET</varname>, <varname>$SYSTEMD_LOG_LEVEL</varname>, <varname>$SYSTEMD_LOG_COLOR</varname>, <varname>$SYSTEMD_LOG_LOCATION</varname> | |
| 1075 | environment variables described above.</para></listitem> | |
| 1076 | </varlistentry> | |
| 1077 | ||
| 0a494f1f LP |
1078 | <varlistentry> |
| 1079 | <term><varname>systemd.default_standard_output=</varname></term> | |
| 1080 | <term><varname>systemd.default_standard_error=</varname></term> | |
| 1081 | <listitem><para>Controls default | |
| 16dad32e | 1082 | standard output and error output for |
| 0a494f1f LP |
1083 | services, with the same effect as the |
| 1084 | <option>--default-standard-output=</option> | |
| 16dad32e | 1085 | and <option>--default-standard-error=</option> |
| 0a494f1f | 1086 | command line arguments described |
| 16dad32e | 1087 | above, respectively.</para></listitem> |
| 0a494f1f LP |
1088 | </varlistentry> |
| 1089 | ||
| aa704ba8 LP |
1090 | <varlistentry> |
| 1091 | <term><varname>systemd.setenv=</varname></term> | |
| 1092 | ||
| 1093 | <listitem><para>Takes a string | |
| e21fea24 KS |
1094 | argument in the form VARIABLE=VALUE. |
| 1095 | May be used to set default environment | |
| 1096 | variables to add to forked child processes. | |
| 1097 | May be used more than once to set multiple | |
| 1098 | variables.</para></listitem> | |
| aa704ba8 LP |
1099 | </varlistentry> |
| 1100 | ||
| c66e7bc7 LP |
1101 | <varlistentry> |
| 1102 | <term><varname>quiet</varname></term> | |
| 1103 | ||
| 9749cd77 | 1104 | <listitem><para>Turn off |
| d081dffb | 1105 | status output at boot, much like |
| c66e7bc7 | 1106 | <varname>systemd.show_status=false</varname> |
| c66e7bc7 LP |
1107 | would. Note that this option is also |
| 1108 | read by the kernel itself and disables | |
| 9749cd77 LN |
1109 | kernel log output. Passing this option |
| 1110 | hence turns off the usual output from | |
| 1111 | both the system manager and the kernel. | |
| 1112 | </para></listitem> | |
| 1113 | </varlistentry> | |
| 1114 | ||
| 1115 | <varlistentry> | |
| 1116 | <term><varname>debug</varname></term> | |
| 1117 | ||
| 1118 | <listitem><para>Turn on debugging | |
| 1119 | output. This is equivalent to | |
| 1120 | <varname>systemd.log_level=debug</varname>. | |
| 1121 | Note that this option is also read by | |
| 1122 | the kernel itself and enables kernel | |
| 1123 | debug output. Passing this option | |
| 1124 | hence turns on the debug output from | |
| 1125 | both the system manager and the | |
| c66e7bc7 LP |
1126 | kernel.</para></listitem> |
| 1127 | </varlistentry> | |
| 1128 | ||
| 1129 | <varlistentry> | |
| 1130 | <term><varname>emergency</varname></term> | |
| f280bcfb | 1131 | <term><varname>-b</varname></term> |
| c66e7bc7 LP |
1132 | |
| 1133 | <listitem><para>Boot into emergency | |
| 1134 | mode. This is equivalent to | |
| 1135 | <varname>systemd.unit=emergency.target</varname> | |
| f280bcfb LP |
1136 | and provided for compatibility reasons |
| 1137 | and to be easier to | |
| 1138 | type.</para></listitem> | |
| c66e7bc7 LP |
1139 | </varlistentry> |
| 1140 | ||
| 1141 | <varlistentry> | |
| f280bcfb | 1142 | <term><varname>rescue</varname></term> |
| c66e7bc7 LP |
1143 | <term><varname>single</varname></term> |
| 1144 | <term><varname>s</varname></term> | |
| 1145 | <term><varname>S</varname></term> | |
| 1146 | <term><varname>1</varname></term> | |
| 1147 | ||
| 1148 | <listitem><para>Boot into rescue | |
| 1149 | mode. This is equivalent to | |
| 1150 | <varname>systemd.unit=rescue.target</varname> | |
| 1151 | and provided for compatibility reasons | |
| 1152 | and to be easier to | |
| 1153 | type.</para></listitem> | |
| 1154 | </varlistentry> | |
| 1155 | ||
| 1156 | <varlistentry> | |
| 1157 | <term><varname>2</varname></term> | |
| 1158 | <term><varname>3</varname></term> | |
| 1159 | <term><varname>4</varname></term> | |
| 1160 | <term><varname>5</varname></term> | |
| 1161 | ||
| 1162 | <listitem><para>Boot into the | |
| 16dad32e AE |
1163 | specified legacy SysV runlevel. These |
| 1164 | are equivalent to | |
| c66e7bc7 LP |
1165 | <varname>systemd.unit=runlevel2.target</varname>, |
| 1166 | <varname>systemd.unit=runlevel3.target</varname>, | |
| 1167 | <varname>systemd.unit=runlevel4.target</varname>, | |
| 16dad32e | 1168 | and <varname>systemd.unit=runlevel5.target</varname>, respectively, |
| c66e7bc7 LP |
1169 | and provided for compatibility reasons |
| 1170 | and to be easier to | |
| 1171 | type.</para></listitem> | |
| 1172 | </varlistentry> | |
| 1173 | ||
| 1174 | <varlistentry> | |
| 1175 | <term><varname>locale.LANG=</varname></term> | |
| 1176 | <term><varname>locale.LANGUAGE=</varname></term> | |
| 1177 | <term><varname>locale.LC_CTYPE=</varname></term> | |
| 1178 | <term><varname>locale.LC_NUMERIC=</varname></term> | |
| 1179 | <term><varname>locale.LC_TIME=</varname></term> | |
| 1180 | <term><varname>locale.LC_COLLATE=</varname></term> | |
| 1181 | <term><varname>locale.LC_MONETARY=</varname></term> | |
| 1182 | <term><varname>locale.LC_MESSAGES=</varname></term> | |
| 1183 | <term><varname>locale.LC_PAPER=</varname></term> | |
| 1184 | <term><varname>locale.LC_NAME=</varname></term> | |
| 1185 | <term><varname>locale.LC_ADDRESS=</varname></term> | |
| 1186 | <term><varname>locale.LC_TELEPHONE=</varname></term> | |
| 1187 | <term><varname>locale.LC_MEASUREMENT=</varname></term> | |
| 1188 | <term><varname>locale.LC_IDENTIFICATION=</varname></term> | |
| 1189 | ||
| 1190 | <listitem><para>Set the system locale | |
| 1191 | to use. This overrides the settings in | |
| 1192 | <filename>/etc/locale.conf</filename>. For | |
| 1193 | more information see | |
| 1194 | <citerefentry><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
| 1195 | and | |
| 1196 | <citerefentry><refentrytitle>locale</refentrytitle><manvolnum>7</manvolnum></citerefentry>. | |
| 1197 | </para></listitem> | |
| 1198 | </varlistentry> | |
| f3e219a2 | 1199 | </variablelist> |
| c66e7bc7 LP |
1200 | |
| 1201 | <para>For other kernel command line parameters | |
| 1202 | understood by components of the core OS, please refer | |
| 1203 | to | |
| 1204 | <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> | |
| f3e219a2 LP |
1205 | </refsect1> |
| 1206 | ||
| 2218198b LP |
1207 | <refsect1> |
| 1208 | <title>Sockets and FIFOs</title> | |
| 1209 | ||
| 1210 | <variablelist> | |
| 1211 | <varlistentry> | |
| bb29785e | 1212 | <term><filename>/run/systemd/notify</filename></term> |
| 2218198b LP |
1213 | |
| 1214 | <listitem><para>Daemon status | |
| bb29785e | 1215 | notification socket. This is an |
| 74d00578 | 1216 | <constant>AF_UNIX</constant> datagram socket and is used to |
| bb29785e LP |
1217 | implement the daemon notification |
| 1218 | logic as implemented by | |
| 2218198b LP |
1219 | <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem> |
| 1220 | ||
| 1221 | </varlistentry> | |
| 1222 | ||
| 5dc50792 | 1223 | <varlistentry> |
| bb29785e | 1224 | <term><filename>/run/systemd/shutdownd</filename></term> |
| 5dc50792 LP |
1225 | |
| 1226 | <listitem><para>Used internally by the | |
| 1227 | <citerefentry><refentrytitle>shutdown</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
| 1228 | tool to implement delayed | |
| 74d00578 | 1229 | shutdowns. This is an <constant>AF_UNIX</constant> datagram |
| bb29785e | 1230 | socket.</para></listitem> |
| 5dc50792 LP |
1231 | </varlistentry> |
| 1232 | ||
| 2218198b | 1233 | <varlistentry> |
| bb29785e | 1234 | <term><filename>/run/systemd/private</filename></term> |
| 2218198b LP |
1235 | |
| 1236 | <listitem><para>Used internally as | |
| 1237 | communication channel between | |
| 1238 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
| 1239 | and the systemd process. This is an | |
| 74d00578 | 1240 | <constant>AF_UNIX</constant> stream socket. This interface |
| bb29785e LP |
1241 | is private to systemd and should not |
| 1242 | be used in external | |
| 2218198b LP |
1243 | projects.</para></listitem> |
| 1244 | </varlistentry> | |
| 1245 | ||
| 1246 | <varlistentry> | |
| 1247 | <term><filename>/dev/initctl</filename></term> | |
| 1248 | ||
| 1249 | <listitem><para>Limited compatibility | |
| 1250 | support for the SysV client interface, | |
| 1251 | as implemented by the | |
| 1252 | <filename>systemd-initctl.service</filename> | |
| 1253 | unit. This is a named pipe in the file | |
| 1254 | system. This interface is obsolete and | |
| 1255 | should not be used in new | |
| 1256 | applications.</para></listitem> | |
| 1257 | </varlistentry> | |
| 1258 | </variablelist> | |
| 9e632bf7 LP |
1259 | </refsect1> |
| 1260 | ||
| 9e632bf7 LP |
1261 | <refsect1> |
| 1262 | <title>See Also</title> | |
| 1263 | <para> | |
| ba54bcb8 | 1264 | The <ulink url="http://www.freedesktop.org/wiki/Software/systemd/">systemd Homepage</ulink>, |
| 5f9cfd4c | 1265 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| 4aa6e778 | 1266 | <citerefentry><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| 7874bcd6 | 1267 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| 1638bd34 | 1268 | <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| 7874bcd6 | 1269 | <citerefentry><refentrytitle>systemd-notify</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| 9e632bf7 | 1270 | <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
| cb07866b | 1271 | <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| 7874bcd6 LP |
1272 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| 1273 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
| 5aded369 | 1274 | <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| 013d8a39 | 1275 | <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
| 5aded369 | 1276 | <citerefentry project='man-pages'><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
| 9cc2c8b7 | 1277 | <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
| 9e632bf7 LP |
1278 | </para> |
| 1279 | </refsect1> | |
| 1280 | ||
| 1281 | </refentry> |