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 | |
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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 |
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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> | |
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77 | |
| 78 | <para>When run as system instance, systemd interprets | |
| 79 | the configuration file | |
| 80 | <filename>system.conf</filename>, otherwise | |
| af2d49f7 | 81 | <filename>user.conf</filename>. See |
| 5f9cfd4c | 82 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
| f3e219a2 | 83 | for more information.</para> |
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84 | </refsect1> |
| 85 | ||
| 86 | <refsect1> | |
| 87 | <title>Options</title> | |
| 88 | ||
| 89 | <para>The following options are understood:</para> | |
| 90 | ||
| 91 | <variablelist> | |
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92 | <varlistentry> |
| 93 | <term><option>--test</option></term> | |
| 94 | ||
| 95 | <listitem><para>Determine startup | |
| 96 | sequence, dump it and exit. This is an | |
| 97 | option useful for debugging | |
| 98 | only.</para></listitem> | |
| 99 | </varlistentry> | |
| 100 | <varlistentry> | |
| 101 | <term><option>--dump-configuration-items</option></term> | |
| 102 | ||
| 103 | <listitem><para>Dump understood unit | |
| 104 | configuration items. This outputs a | |
| 105 | terse but complete list of | |
| 106 | configuration items understood in unit | |
| 107 | definition files.</para></listitem> | |
| 108 | </varlistentry> | |
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109 | <varlistentry> |
| 110 | <term><option>--unit=</option></term> | |
| 111 | ||
| 112 | <listitem><para>Set default unit to | |
| 79640424 | 113 | activate on startup. If not specified, |
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114 | defaults to |
| 115 | <filename>default.target</filename>.</para></listitem> | |
| 116 | </varlistentry> | |
| 117 | <varlistentry> | |
| edb9aaa8 | 118 | <term><option>--system</option></term> |
| af2d49f7 | 119 | <term><option>--user</option></term> |
| edb9aaa8 | 120 | |
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121 | <listitem><para>For <option>--system</option>, |
| 122 | tell systemd to run a | |
| 123 | system instance, even if the process ID is | |
| 124 | not 1, i.e. systemd is not run as init process. | |
| 125 | <option>--user</option> does the opposite, | |
| 126 | running a user instance even if the process | |
| 127 | ID is 1. | |
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128 | Normally it should not be necessary to |
| 129 | pass these options, as systemd | |
| 130 | automatically detects the mode it is | |
| 131 | started in. These options are hence of | |
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132 | little use except for debugging. Note |
| 133 | that it is not supported booting and | |
| 134 | maintaining a full system with systemd | |
| 135 | running in <option>--system</option> | |
| 136 | mode, but PID not 1. In practice, | |
| 137 | passing <option>--system</option> explicitly is | |
| 138 | only useful in conjunction with | |
| 139 | <option>--test</option>.</para></listitem> | |
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140 | </varlistentry> |
| 141 | <varlistentry> | |
| f3e219a2 | 142 | <term><option>--dump-core</option></term> |
| 2218198b | 143 | |
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144 | <listitem><para>Dump core on |
| 145 | crash. This switch has no effect when | |
| 146 | run as user | |
| 147 | instance.</para></listitem> | |
| 2218198b LP |
148 | </varlistentry> |
| 149 | <varlistentry> | |
| f3e219a2 | 150 | <term><option>--crash-shell</option></term> |
| 2218198b | 151 | |
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152 | <listitem><para>Run shell on |
| 153 | crash. This switch has no effect when | |
| 154 | run as user | |
| 155 | instance.</para></listitem> | |
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156 | </varlistentry> |
| 157 | <varlistentry> | |
| 158 | <term><option>--confirm-spawn</option></term> | |
| 159 | ||
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160 | <listitem><para>Ask for confirmation |
| 161 | when spawning processes. This switch | |
| 162 | has no effect when run as user | |
| 163 | instance.</para></listitem> | |
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164 | </varlistentry> |
| 165 | <varlistentry> | |
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166 | <term><option>--show-status=</option></term> |
| 167 | ||
| 168 | <listitem><para>Show terse service | |
| 169 | status information while booting. This | |
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170 | switch has no effect when run as user |
| 171 | instance. Takes a boolean argument | |
| 172 | which may be omitted which is | |
| 173 | interpreted as | |
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174 | <option>true</option>.</para></listitem> |
| 175 | </varlistentry> | |
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176 | <varlistentry> |
| 177 | <term><option>--log-target=</option></term> | |
| 178 | ||
| 179 | <listitem><para>Set log | |
| 180 | target. Argument must be one of | |
| 181 | <option>console</option>, | |
| 4cfa2c99 | 182 | <option>journal</option>, |
| f3e219a2 | 183 | <option>kmsg</option>, |
| 4cfa2c99 | 184 | <option>journal-or-kmsg</option>, |
| f3e219a2 | 185 | <option>null</option>.</para></listitem> |
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186 | </varlistentry> |
| 187 | <varlistentry> | |
| 188 | <term><option>--log-level=</option></term> | |
| 189 | ||
| 190 | <listitem><para>Set log level. As | |
| 191 | argument this accepts a numerical log | |
| 5aded369 | 192 | level or the well-known <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
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193 | symbolic names (lowercase): |
| 194 | <option>emerg</option>, | |
| 195 | <option>alert</option>, | |
| 196 | <option>crit</option>, | |
| 197 | <option>err</option>, | |
| 198 | <option>warning</option>, | |
| 199 | <option>notice</option>, | |
| 200 | <option>info</option>, | |
| 201 | <option>debug</option>.</para></listitem> | |
| 202 | </varlistentry> | |
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203 | <varlistentry> |
| 204 | <term><option>--log-color=</option></term> | |
| 205 | ||
| 206 | <listitem><para>Highlight important | |
| 207 | log messages. Argument is a boolean | |
| 79640424 | 208 | value. If the argument is omitted, it |
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209 | defaults to |
| 210 | <option>true</option>.</para></listitem> | |
| 211 | </varlistentry> | |
| 212 | <varlistentry> | |
| 213 | <term><option>--log-location=</option></term> | |
| 214 | ||
| 215 | <listitem><para>Include code location | |
| 216 | in log messages. This is mostly | |
| 217 | relevant for debugging | |
| 218 | purposes. Argument is a boolean | |
| 219 | value. If the argument is omitted | |
| 220 | it defaults to | |
| 221 | <option>true</option>.</para></listitem> | |
| 222 | </varlistentry> | |
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223 | <varlistentry> |
| 224 | <term><option>--default-standard-output=</option></term> | |
| 225 | <term><option>--default-standard-error=</option></term> | |
| 226 | ||
| 227 | <listitem><para>Sets the default | |
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228 | output or error output for all |
| 229 | services and sockets, respectively. That is, controls | |
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230 | the default for |
| 231 | <option>StandardOutput=</option> | |
| 16dad32e | 232 | and <option>StandardError=</option> |
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233 | (see |
| 234 | <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
| 235 | for details). Takes one of | |
| 236 | <option>inherit</option>, | |
| 237 | <option>null</option>, | |
| 238 | <option>tty</option>, | |
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239 | <option>journal</option>, |
| 240 | <option>journal+console</option>, | |
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241 | <option>syslog</option>, |
| 242 | <option>syslog+console</option>, | |
| 243 | <option>kmsg</option>, | |
| 756a8d17 | 244 | <option>kmsg+console</option>. If the |
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245 | argument is omitted |
| 246 | <option>--default-standard-output=</option> | |
| 4cfa2c99 | 247 | defaults to <option>journal</option> |
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248 | and |
| 249 | <option>--default-standard-error=</option> | |
| 250 | to | |
| 934da035 | 251 | <option>inherit</option>.</para></listitem> |
| 0a494f1f | 252 | </varlistentry> |
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253 | |
| 254 | <xi:include href="standard-options.xml" xpointer="help" /> | |
| 255 | <xi:include href="standard-options.xml" xpointer="version" /> | |
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256 | </variablelist> |
| 257 | </refsect1> | |
| 258 | ||
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259 | <refsect1> |
| 260 | <title>Concepts</title> | |
| 261 | ||
| 262 | <para>systemd provides a dependency system between | |
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263 | various entities called "units" of 12 different |
| 264 | types. Units encapsulate various objects that are | |
| 265 | relevant for system boot-up and maintenance. The | |
| 266 | majority of units are configured in unit configuration | |
| 267 | files, whose syntax and basic set of options is | |
| 268 | described in | |
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269 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| 270 | however some are created automatically from other | |
| 1ec96668 | 271 | configuration, dynamically from system state or |
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272 | programmatically at runtime. Units may be "active" |
| 273 | (meaning started, bound, plugged in, ..., depending on | |
| 274 | the unit type, see below), or "inactive" (meaning | |
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275 | stopped, unbound, unplugged, ...), as well as in the |
| 276 | process of being activated or deactivated, | |
| 277 | i.e. between the two states (these states are called | |
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278 | "activating", "deactivating"). A special "failed" |
| 279 | state is available as well, which is very similar to | |
| 280 | "inactive" and is entered when the service failed in | |
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281 | some way (process returned error code on exit, or |
| 282 | crashed, or an operation timed out). If this state is | |
| fbce1139 | 283 | entered, the cause will be logged, for later |
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284 | reference. Note that the various unit types may have a |
| 285 | number of additional substates, which are mapped to | |
| 286 | the five generalized unit states described | |
| 287 | here.</para> | |
| 288 | ||
| 289 | <para>The following unit types are available:</para> | |
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290 | |
| 291 | <orderedlist> | |
| 1ec96668 | 292 | <listitem><para>Service units, which start and control |
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293 | daemons and the processes they consist of. For |
| 294 | details see | |
| 295 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 296 | ||
| 297 | <listitem><para>Socket units, which | |
| 298 | encapsulate local IPC or network sockets in | |
| 299 | the system, useful for socket-based | |
| 300 | activation. For details about socket units see | |
| 301 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
| 302 | for details on socket-based activation and | |
| 303 | other forms of activation, see | |
| 304 | <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para></listitem> | |
| 305 | ||
| 306 | <listitem><para>Target units are useful to | |
| 307 | group units, or provide well-known | |
| 308 | synchronization points during boot-up, see | |
| 309 | <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 310 | ||
| 311 | <listitem><para>Device units expose kernel | |
| 312 | devices in systemd and may be used to | |
| 313 | implement device-based activation. For details | |
| 314 | see | |
| 315 | <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 316 | ||
| 317 | <listitem><para>Mount units control mount | |
| 318 | points in the file system, for details see | |
| 319 | <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 320 | ||
| 321 | <listitem><para>Automount units provide | |
| 322 | automount capabilities, for on-demand mounting | |
| 323 | of file systems as well as parallelized | |
| 324 | boot-up. See | |
| 325 | <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 326 | ||
| 327 | <listitem><para>Snapshot units can be used to | |
| 328 | temporarily save the state of the set of | |
| 329 | systemd units, which later may be restored by | |
| 330 | activating the saved snapshot unit. For more | |
| 331 | information see | |
| 7461d1b7 | 332 | <citerefentry><refentrytitle>systemd.snapshot</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
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333 | |
| 334 | <listitem><para>Timer units are useful for | |
| 335 | triggering activation of other units based on | |
| 336 | timers. You may find details in | |
| 337 | <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 338 | ||
| 339 | <listitem><para>Swap units are very similar to | |
| f8553ccb | 340 | mount units and encapsulate memory swap |
| 99ffae46 | 341 | partitions or files of the operating |
| f8553ccb | 342 | system. They are described in <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
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343 | |
| 344 | <listitem><para>Path units may be used | |
| dccb2600 | 345 | to activate other services when file system |
| 99ffae46 LP |
346 | objects change or are modified. See |
| 347 | <citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 348 | ||
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349 | <listitem><para>Slice units may be used to |
| 350 | group units which manage system processes | |
| 351 | (such as service and scope units) in a | |
| 5eec7de6 | 352 | hierarchical tree for resource management |
| 1ec96668 LP |
353 | purposes. See |
| 354 | <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 355 | ||
| 356 | <listitem><para>Scope units are similar to | |
| 357 | service units, but manage foreign processes | |
| 358 | instead of starting them as well. See | |
| 359 | <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
| 360 | ||
| 99ffae46 LP |
361 | </orderedlist> |
| 362 | ||
| 363 | <para>Units are named as their configuration | |
| 364 | files. Some units have special semantics. A detailed | |
| f8553ccb | 365 | list is available in |
| 99ffae46 LP |
366 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> |
| 367 | ||
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368 | <para>systemd knows various kinds of dependencies, |
| 369 | including positive and negative requirement | |
| 370 | dependencies (i.e. <varname>Requires=</varname> and | |
| 371 | <varname>Conflicts=</varname>) as well as ordering | |
| 372 | dependencies (<varname>After=</varname> and | |
| 373 | <varname>Before=</varname>). NB: ordering and | |
| 374 | requirement dependencies are orthogonal. If only a | |
| 375 | requirement dependency exists between two units | |
| 376 | (e.g. <filename>foo.service</filename> requires | |
| 377 | <filename>bar.service</filename>), but no ordering | |
| 378 | dependency (e.g. <filename>foo.service</filename> | |
| 379 | after <filename>bar.service</filename>) and both are | |
| 380 | requested to start, they will be started in | |
| 381 | parallel. It is a common pattern that both requirement | |
| 382 | and ordering dependencies are placed between two | |
| 383 | units. Also note that the majority of dependencies are | |
| 384 | implicitly created and maintained by systemd. In most | |
| 73e231ab | 385 | cases, it should be unnecessary to declare additional |
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386 | dependencies manually, however it is possible to do |
| 387 | this.</para> | |
| 388 | ||
| 389 | <para>Application programs and units (via | |
| f8553ccb | 390 | dependencies) may request state changes of units. In |
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391 | systemd, these requests are encapsulated as 'jobs' and |
| 392 | maintained in a job queue. Jobs may succeed or can | |
| 393 | fail, their execution is ordered based on the ordering | |
| 394 | dependencies of the units they have been scheduled | |
| 395 | for.</para> | |
| 396 | ||
| 99ffae46 | 397 | <para>On boot systemd activates the target unit |
| dccb2600 | 398 | <filename>default.target</filename> whose job is to |
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399 | activate on-boot services and other on-boot units by |
| 400 | pulling them in via dependencies. Usually the unit | |
| 401 | name is just an alias (symlink) for either | |
| 402 | <filename>graphical.target</filename> (for | |
| 403 | fully-featured boots into the UI) or | |
| 404 | <filename>multi-user.target</filename> (for limited | |
| 405 | console-only boots for use in embedded or server | |
| 406 | environments, or similar; a subset of | |
| 79640424 | 407 | graphical.target). However, it is at the discretion of |
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408 | the administrator to configure it as an alias to any |
| 409 | other target unit. See | |
| 410 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
| 411 | for details about these target units.</para> | |
| 412 | ||
| dccb2600 | 413 | <para>Processes systemd spawns are placed in |
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414 | individual Linux control groups named after the unit |
| 415 | which they belong to in the private systemd | |
| 416 | hierarchy. (see <ulink | |
| 6ed80a4e | 417 | url="https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink> |
| 59a3e1bc LP |
418 | for more information about control groups, or short |
| 419 | "cgroups"). systemd uses this to effectively keep | |
| 420 | track of processes. Control group information is | |
| 421 | maintained in the kernel, and is accessible via the | |
| 422 | file system hierarchy (beneath | |
| 77d5f105 | 423 | <filename>/sys/fs/cgroup/systemd/</filename>), or in tools |
| 59a3e1bc | 424 | such as |
| 5aded369 | 425 | <citerefentry project='man-pages'><refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
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426 | (<command>ps xawf -eo pid,user,cgroup,args</command> |
| 427 | is particularly useful to list all processes and the | |
| 428 | systemd units they belong to.).</para> | |
| 429 | ||
| 430 | <para>systemd is compatible with the SysV init system | |
| 431 | to a large degree: SysV init scripts are supported and | |
| 432 | simply read as an alternative (though limited) | |
| 433 | configuration file format. The SysV | |
| 434 | <filename>/dev/initctl</filename> interface is | |
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435 | provided, and compatibility implementations of the |
| 436 | various SysV client tools are available. In addition to | |
| 437 | that, various established Unix functionality such as | |
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438 | <filename>/etc/fstab</filename> or the |
| 439 | <filename>utmp</filename> database are | |
| 440 | supported.</para> | |
| 441 | ||
| 442 | <para>systemd has a minimal transaction system: if a | |
| 443 | unit is requested to start up or shut down it will add | |
| 444 | it and all its dependencies to a temporary | |
| 445 | transaction. Then, it will verify if the transaction | |
| 446 | is consistent (i.e. whether the ordering of all units | |
| 447 | is cycle-free). If it is not, systemd will try to fix | |
| 448 | it up, and removes non-essential jobs from the | |
| 449 | transaction that might remove the loop. Also, systemd | |
| 450 | tries to suppress non-essential jobs in the | |
| 451 | transaction that would stop a running service. Finally | |
| 452 | it is checked whether the jobs of the transaction | |
| 453 | contradict jobs that have already been queued, and | |
| 454 | optionally the transaction is aborted then. If all | |
| 455 | worked out and the transaction is consistent and | |
| 456 | minimized in its impact it is merged with all already | |
| 457 | outstanding jobs and added to the run | |
| 458 | queue. Effectively this means that before executing a | |
| 459 | requested operation, systemd will verify that it makes | |
| 460 | sense, fixing it if possible, and only failing if it | |
| 461 | really cannot work.</para> | |
| 462 | ||
| 463 | <para>Systemd contains native implementations of | |
| 464 | various tasks that need to be executed as part of the | |
| e9dd9f95 | 465 | boot process. For example, it sets the hostname or |
| 59a3e1bc LP |
466 | configures the loopback network device. It also sets |
| 467 | up and mounts various API file systems, such as | |
| 468 | <filename>/sys</filename> or | |
| 469 | <filename>/proc</filename>.</para> | |
| 470 | ||
| 99ffae46 | 471 | <para>For more information about the concepts and |
| b040723e | 472 | ideas behind systemd, please refer to the <ulink |
| 99ffae46 | 473 | url="http://0pointer.de/blog/projects/systemd.html">Original |
| 59a3e1bc | 474 | Design Document</ulink>.</para> |
| b9aea954 LP |
475 | |
| 476 | <para>Note that some but not all interfaces provided | |
| 477 | by systemd are covered by the <ulink | |
| 478 | url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface | |
| 479 | Stability Promise</ulink>.</para> | |
| 059b37cc LP |
480 | |
| 481 | <para>Units may be generated dynamically at boot and | |
| 482 | system manager reload time, for example based on other | |
| 483 | configuration files or parameters passed on the kernel | |
| 484 | command line. For details see the <ulink | |
| 485 | url="http://www.freedesktop.org/wiki/Software/systemd/Generators">Generators | |
| 486 | Specification</ulink>.</para> | |
| 99800333 LP |
487 | |
| 488 | <para>Systems which invoke systemd in a container | |
| 16dad32e | 489 | or initrd environment should implement the |
| 99800333 LP |
490 | <ulink |
| 491 | url="http://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container | |
| 16dad32e | 492 | Interface</ulink> or <ulink |
| 99800333 | 493 | url="http://www.freedesktop.org/wiki/Software/systemd/InitrdInterface">initrd |
| 16dad32e | 494 | Interface</ulink> specifications, respectively.</para> |
| 99ffae46 LP |
495 | </refsect1> |
| 496 | ||
| 160cd5c9 LP |
497 | <refsect1> |
| 498 | <title>Directories</title> | |
| 7874bcd6 | 499 | |
| 19adb8a3 | 500 | <variablelist> |
| 7874bcd6 LP |
501 | <varlistentry> |
| 502 | <term>System unit directories</term> | |
| 503 | ||
| 504 | <listitem><para>The systemd system | |
| 505 | manager reads unit configuration from | |
| 506 | various directories. Packages that | |
| 507 | want to install unit files shall place | |
| 508 | them in the directory returned by | |
| 509 | <command>pkg-config systemd | |
| 510 | --variable=systemdsystemunitdir</command>. Other | |
| 511 | directories checked are | |
| d636fa3d | 512 | <filename>/usr/local/lib/systemd/system</filename> |
| 7874bcd6 | 513 | and |
| d636fa3d | 514 | <filename>/usr/lib/systemd/system</filename>. User |
| 7874bcd6 LP |
515 | configuration always takes |
| 516 | precedence. <command>pkg-config | |
| 517 | systemd | |
| 518 | --variable=systemdsystemconfdir</command> | |
| 519 | returns the path of the system | |
| 520 | configuration directory. Packages | |
| ee5762e3 LP |
521 | should alter the content of these |
| 522 | directories only with the | |
| 523 | <command>enable</command> and | |
| 524 | <command>disable</command> commands of | |
| 525 | the | |
| 526 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
| 13219b7f ZJS |
527 | tool. Full list of directories is provided in |
| 528 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. | |
| 529 | </para></listitem> | |
| 7874bcd6 LP |
530 | </varlistentry> |
| 531 | </variablelist> | |
| 532 | ||
| 533 | <variablelist> | |
| 534 | <varlistentry> | |
| af2d49f7 | 535 | <term>User unit directories</term> |
| 7874bcd6 LP |
536 | |
| 537 | <listitem><para>Similar rules apply | |
| af2d49f7 | 538 | for the user unit |
| 7874bcd6 LP |
539 | directories. However, here the <ulink |
| 540 | url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG | |
| 541 | Base Directory specification</ulink> | |
| 542 | is followed to find | |
| 543 | units. Applications should place their | |
| 544 | unit files in the directory returned | |
| 545 | by <command>pkg-config systemd | |
| af2d49f7 | 546 | --variable=systemduserunitdir</command>. Global |
| ee5762e3 LP |
547 | configuration is done in the directory |
| 548 | reported by <command>pkg-config | |
| 549 | systemd | |
| af2d49f7 | 550 | --variable=systemduserconfdir</command>. The |
| ee5762e3 LP |
551 | <command>enable</command> and |
| 552 | <command>disable</command> commands of | |
| 553 | the | |
| 554 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
| 7874bcd6 LP |
555 | tool can handle both global (i.e. for |
| 556 | all users) and private (for one user) | |
| 557 | enabling/disabling of | |
| 13219b7f ZJS |
558 | units. Full list of directories is provided in |
| 559 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. | |
| 560 | </para></listitem> | |
| 7874bcd6 LP |
561 | </varlistentry> |
| 562 | </variablelist> | |
| 563 | ||
| 564 | <variablelist> | |
| 565 | <varlistentry> | |
| 566 | <term>SysV init scripts directory</term> | |
| 567 | ||
| 568 | <listitem><para>The location of the | |
| 569 | SysV init script directory varies | |
| 570 | between distributions. If systemd | |
| 571 | cannot find a native unit file for a | |
| af62c704 | 572 | requested service, it will look for a |
| 7874bcd6 LP |
573 | SysV init script of the same name |
| 574 | (with the | |
| 575 | <filename>.service</filename> suffix | |
| 576 | removed).</para></listitem> | |
| 577 | </varlistentry> | |
| 578 | </variablelist> | |
| 579 | ||
| 580 | <variablelist> | |
| 581 | <varlistentry> | |
| 582 | <term>SysV runlevel link farm directory</term> | |
| 583 | ||
| 584 | <listitem><para>The location of the | |
| 585 | SysV runlevel link farm directory | |
| 586 | varies between distributions. systemd | |
| 587 | will take the link farm into account | |
| 588 | when figuring out whether a service | |
| 589 | shall be enabled. Note that a service | |
| 590 | unit with a native unit configuration | |
| edb9aaa8 | 591 | file cannot be started by activating it |
| 7874bcd6 LP |
592 | in the SysV runlevel link |
| 593 | farm.</para></listitem> | |
| 594 | </varlistentry> | |
| 595 | </variablelist> | |
| 160cd5c9 LP |
596 | </refsect1> |
| 597 | ||
| 598 | <refsect1> | |
| 7874bcd6 | 599 | <title>Signals</title> |
| 160cd5c9 LP |
600 | |
| 601 | <variablelist> | |
| 602 | <varlistentry> | |
| 74d00578 | 603 | <term><constant>SIGTERM</constant></term> |
| 7874bcd6 LP |
604 | |
| 605 | <listitem><para>Upon receiving this | |
| 606 | signal the systemd system manager | |
| 607 | serializes its state, reexecutes | |
| 608 | itself and deserializes the saved | |
| 609 | state again. This is mostly equivalent | |
| 610 | to <command>systemctl | |
| 611 | daemon-reexec</command>.</para> | |
| 612 | ||
| af2d49f7 | 613 | <para>systemd user managers will |
| 7874bcd6 LP |
614 | start the |
| 615 | <filename>exit.target</filename> unit | |
| 616 | when this signal is received. This is | |
| 617 | mostly equivalent to | |
| af2d49f7 | 618 | <command>systemctl --user start |
| 7874bcd6 LP |
619 | exit.target</command>.</para></listitem> |
| 620 | </varlistentry> | |
| 621 | ||
| 622 | <varlistentry> | |
| 74d00578 | 623 | <term><constant>SIGINT</constant></term> |
| 7874bcd6 LP |
624 | |
| 625 | <listitem><para>Upon receiving this | |
| 626 | signal the systemd system manager will | |
| 627 | start the | |
| 628 | <filename>ctrl-alt-del.target</filename> unit. This | |
| 629 | is mostly equivalent to | |
| 630 | <command>systemctl start | |
| 631 | ctl-alt-del.target</command>.</para> | |
| 632 | ||
| af2d49f7 | 633 | <para>systemd user managers |
| 7874bcd6 | 634 | treat this signal the same way as |
| 05cc7267 | 635 | <constant>SIGTERM</constant>.</para></listitem> |
| 7874bcd6 LP |
636 | </varlistentry> |
| 637 | ||
| 638 | <varlistentry> | |
| 74d00578 | 639 | <term><constant>SIGWINCH</constant></term> |
| 7874bcd6 LP |
640 | |
| 641 | <listitem><para>When this signal is | |
| 642 | received the systemd system manager | |
| 643 | will start the | |
| 644 | <filename>kbrequest.target</filename> | |
| 645 | unit. This is mostly equivalent to | |
| 646 | <command>systemctl start | |
| 647 | kbrequest.target</command>.</para> | |
| 648 | ||
| 649 | <para>This signal is ignored by | |
| af2d49f7 | 650 | systemd user |
| 7874bcd6 LP |
651 | managers.</para></listitem> |
| 652 | </varlistentry> | |
| 653 | ||
| 654 | <varlistentry> | |
| 74d00578 | 655 | <term><constant>SIGPWR</constant></term> |
| 7874bcd6 LP |
656 | |
| 657 | <listitem><para>When this signal is | |
| 658 | received the systemd manager | |
| 659 | will start the | |
| 660 | <filename>sigpwr.target</filename> | |
| 661 | unit. This is mostly equivalent to | |
| 662 | <command>systemctl start | |
| 663 | sigpwr.target</command>.</para></listitem> | |
| 664 | </varlistentry> | |
| 665 | ||
| 666 | <varlistentry> | |
| 74d00578 | 667 | <term><constant>SIGUSR1</constant></term> |
| 7874bcd6 LP |
668 | |
| 669 | <listitem><para>When this signal is | |
| 670 | received the systemd manager will try | |
| 671 | to reconnect to the D-Bus | |
| 672 | bus.</para></listitem> | |
| 673 | </varlistentry> | |
| 674 | ||
| 675 | <varlistentry> | |
| 74d00578 | 676 | <term><constant>SIGUSR2</constant></term> |
| 7874bcd6 LP |
677 | |
| 678 | <listitem><para>When this signal is | |
| 679 | received the systemd manager will log | |
| 680 | its complete state in human readable | |
| 681 | form. The data logged is the same as | |
| 682 | printed by <command>systemctl | |
| 683 | dump</command>.</para></listitem> | |
| 684 | </varlistentry> | |
| 685 | ||
| 686 | <varlistentry> | |
| 74d00578 | 687 | <term><constant>SIGHUP</constant></term> |
| 7874bcd6 LP |
688 | |
| 689 | <listitem><para>Reloads the complete | |
| 690 | daemon configuration. This is mostly | |
| 691 | equivalent to <command>systemctl | |
| 692 | daemon-reload</command>.</para></listitem> | |
| 693 | </varlistentry> | |
| 694 | ||
| 695 | <varlistentry> | |
| 74d00578 | 696 | <term><constant>SIGRTMIN+0</constant></term> |
| 7874bcd6 LP |
697 | |
| 698 | <listitem><para>Enters default mode, starts the | |
| 699 | <filename>default.target</filename> | |
| 700 | unit. This is mostly equivalent to | |
| 701 | <command>systemctl start | |
| 702 | default.target</command>.</para></listitem> | |
| 703 | </varlistentry> | |
| 704 | ||
| 705 | <varlistentry> | |
| 74d00578 | 706 | <term><constant>SIGRTMIN+1</constant></term> |
| 7874bcd6 LP |
707 | |
| 708 | <listitem><para>Enters rescue mode, | |
| 709 | starts the | |
| 710 | <filename>rescue.target</filename> | |
| 711 | unit. This is mostly equivalent to | |
| 712 | <command>systemctl isolate | |
| 713 | rescue.target</command>.</para></listitem> | |
| 714 | </varlistentry> | |
| 160cd5c9 | 715 | |
| 7874bcd6 | 716 | <varlistentry> |
| 74d00578 | 717 | <term><constant>SIGRTMIN+2</constant></term> |
| 7874bcd6 LP |
718 | |
| 719 | <listitem><para>Enters emergency mode, | |
| 720 | starts the | |
| 721 | <filename>emergency.service</filename> | |
| 722 | unit. This is mostly equivalent to | |
| 723 | <command>systemctl isolate | |
| 724 | emergency.service</command>.</para></listitem> | |
| 725 | </varlistentry> | |
| 726 | ||
| 727 | <varlistentry> | |
| 74d00578 | 728 | <term><constant>SIGRTMIN+3</constant></term> |
| 7874bcd6 LP |
729 | |
| 730 | <listitem><para>Halts the machine, | |
| 731 | starts the | |
| 732 | <filename>halt.target</filename> | |
| 733 | unit. This is mostly equivalent to | |
| 734 | <command>systemctl start | |
| 735 | halt.target</command>.</para></listitem> | |
| 736 | </varlistentry> | |
| 737 | ||
| 738 | <varlistentry> | |
| 74d00578 | 739 | <term><constant>SIGRTMIN+4</constant></term> |
| 7874bcd6 LP |
740 | |
| 741 | <listitem><para>Powers off the machine, | |
| 742 | starts the | |
| 743 | <filename>poweroff.target</filename> | |
| 744 | unit. This is mostly equivalent to | |
| 745 | <command>systemctl start | |
| 746 | poweroff.target</command>.</para></listitem> | |
| 747 | </varlistentry> | |
| 748 | ||
| 749 | <varlistentry> | |
| 74d00578 | 750 | <term><constant>SIGRTMIN+5</constant></term> |
| 7874bcd6 LP |
751 | |
| 752 | <listitem><para>Reboots the machine, | |
| 753 | starts the | |
| 754 | <filename>reboot.target</filename> | |
| 755 | unit. This is mostly equivalent to | |
| 756 | <command>systemctl start | |
| 757 | reboot.target</command>.</para></listitem> | |
| 160cd5c9 | 758 | </varlistentry> |
| 0658666b LP |
759 | |
| 760 | <varlistentry> | |
| 74d00578 | 761 | <term><constant>SIGRTMIN+6</constant></term> |
| 0658666b LP |
762 | |
| 763 | <listitem><para>Reboots the machine via kexec, | |
| 764 | starts the | |
| 765 | <filename>kexec.target</filename> | |
| 766 | unit. This is mostly equivalent to | |
| 767 | <command>systemctl start | |
| 768 | kexec.target</command>.</para></listitem> | |
| 769 | </varlistentry> | |
| 770 | ||
| 771 | <varlistentry> | |
| 74d00578 | 772 | <term><constant>SIGRTMIN+13</constant></term> |
| 0658666b LP |
773 | |
| 774 | <listitem><para>Immediately halts the machine.</para></listitem> | |
| 775 | </varlistentry> | |
| 776 | ||
| 777 | <varlistentry> | |
| 74d00578 | 778 | <term><constant>SIGRTMIN+14</constant></term> |
| 0658666b LP |
779 | |
| 780 | <listitem><para>Immediately powers off the machine.</para></listitem> | |
| 781 | </varlistentry> | |
| 782 | ||
| 783 | <varlistentry> | |
| 74d00578 | 784 | <term><constant>SIGRTMIN+15</constant></term> |
| 0658666b LP |
785 | |
| 786 | <listitem><para>Immediately reboots the machine.</para></listitem> | |
| 787 | </varlistentry> | |
| 788 | ||
| 789 | <varlistentry> | |
| 74d00578 | 790 | <term><constant>SIGRTMIN+16</constant></term> |
| 0658666b LP |
791 | |
| 792 | <listitem><para>Immediately reboots the machine with kexec.</para></listitem> | |
| 793 | </varlistentry> | |
| 794 | ||
| 795 | <varlistentry> | |
| 74d00578 | 796 | <term><constant>SIGRTMIN+20</constant></term> |
| 0658666b LP |
797 | |
| 798 | <listitem><para>Enables display of | |
| 799 | status messages on the console, as | |
| 800 | controlled via | |
| 801 | <varname>systemd.show_status=1</varname> | |
| 802 | on the kernel command | |
| 803 | line.</para></listitem> | |
| 804 | </varlistentry> | |
| 805 | ||
| 806 | <varlistentry> | |
| 74d00578 | 807 | <term><constant>SIGRTMIN+21</constant></term> |
| 0658666b LP |
808 | |
| 809 | <listitem><para>Disables display of | |
| 810 | status messages on the console, as | |
| 811 | controlled via | |
| 812 | <varname>systemd.show_status=0</varname> | |
| 813 | on the kernel command | |
| 814 | line.</para></listitem> | |
| 815 | </varlistentry> | |
| 253ee27a LP |
816 | |
| 817 | <varlistentry> | |
| 74d00578 ZJS |
818 | <term><constant>SIGRTMIN+22</constant></term> |
| 819 | <term><constant>SIGRTMIN+23</constant></term> | |
| 253ee27a LP |
820 | |
| 821 | <listitem><para>Sets the log level to | |
| 822 | <literal>debug</literal> | |
| 16dad32e | 823 | (or <literal>info</literal> on |
| 74d00578 | 824 | <constant>SIGRTMIN+23</constant>), as |
| 253ee27a LP |
825 | controlled via |
| 826 | <varname>systemd.log_level=debug</varname> | |
| 16dad32e | 827 | (or <varname>systemd.log_level=info</varname> |
| 74d00578 | 828 | on <constant>SIGRTMIN+23</constant>) on |
| 253ee27a LP |
829 | the kernel command |
| 830 | line.</para></listitem> | |
| 831 | </varlistentry> | |
| 832 | ||
| 600b704e | 833 | <varlistentry> |
| 74d00578 | 834 | <term><constant>SIGRTMIN+24</constant></term> |
| 600b704e LP |
835 | |
| 836 | <listitem><para>Immediately exits the | |
| 837 | manager (only available for --user | |
| 838 | instances).</para></listitem> | |
| 839 | </varlistentry> | |
| 840 | ||
| 253ee27a | 841 | <varlistentry> |
| 74d00578 ZJS |
842 | <term><constant>SIGRTMIN+26</constant></term> |
| 843 | <term><constant>SIGRTMIN+27</constant></term> | |
| 844 | <term><constant>SIGRTMIN+28</constant></term> | |
| 253ee27a LP |
845 | |
| 846 | <listitem><para>Sets the log level to | |
| ee0e998e LP |
847 | <literal>journal-or-kmsg</literal> (or |
| 848 | <literal>console</literal> on | |
| 74d00578 | 849 | <constant>SIGRTMIN+27</constant>, |
| 16dad32e | 850 | <literal>kmsg</literal> on |
| ee0e998e | 851 | <constant>SIGRTMIN+28</constant>), as |
| 253ee27a | 852 | controlled via |
| 4cfa2c99 | 853 | <varname>systemd.log_target=journal-or-kmsg</varname> |
| ee0e998e LP |
854 | (or |
| 855 | <varname>systemd.log_target=console</varname> | |
| 856 | on <constant>SIGRTMIN+27</constant> or | |
| 16dad32e | 857 | <varname>systemd.log_target=kmsg</varname> |
| ee0e998e LP |
858 | on <constant>SIGRTMIN+28</constant>) |
| 859 | on the kernel command | |
| 253ee27a LP |
860 | line.</para></listitem> |
| 861 | </varlistentry> | |
| 160cd5c9 LP |
862 | </variablelist> |
| 863 | </refsect1> | |
| 864 | ||
| 7874bcd6 LP |
865 | <refsect1> |
| 866 | <title>Environment</title> | |
| 867 | ||
| 08177c85 | 868 | <variablelist class='environment-variables'> |
| 7874bcd6 LP |
869 | <varlistentry> |
| 870 | <term><varname>$SYSTEMD_LOG_LEVEL</varname></term> | |
| 871 | <listitem><para>systemd reads the | |
| 872 | log level from this environment | |
| 436c44a5 | 873 | variable. This can be overridden with |
| 7874bcd6 LP |
874 | <option>--log-level=</option>.</para></listitem> |
| 875 | </varlistentry> | |
| 876 | ||
| 877 | <varlistentry> | |
| 878 | <term><varname>$SYSTEMD_LOG_TARGET</varname></term> | |
| 879 | <listitem><para>systemd reads the | |
| 880 | log target from this environment | |
| 436c44a5 | 881 | variable. This can be overridden with |
| 7874bcd6 LP |
882 | <option>--log-target=</option>.</para></listitem> |
| 883 | </varlistentry> | |
| 884 | ||
| 885 | <varlistentry> | |
| 886 | <term><varname>$SYSTEMD_LOG_COLOR</varname></term> | |
| 887 | <listitem><para>Controls whether | |
| 888 | systemd highlights important log | |
| 436c44a5 | 889 | messages. This can be overridden with |
| 7874bcd6 LP |
890 | <option>--log-color=</option>.</para></listitem> |
| 891 | </varlistentry> | |
| 892 | ||
| 893 | <varlistentry> | |
| 894 | <term><varname>$SYSTEMD_LOG_LOCATION</varname></term> | |
| 895 | <listitem><para>Controls whether | |
| 896 | systemd prints the code location along | |
| 897 | with log messages. This can be | |
| 436c44a5 | 898 | overridden with |
| 7874bcd6 LP |
899 | <option>--log-location=</option>.</para></listitem> |
| 900 | </varlistentry> | |
| 901 | ||
| 902 | <varlistentry> | |
| 903 | <term><varname>$XDG_CONFIG_HOME</varname></term> | |
| 904 | <term><varname>$XDG_CONFIG_DIRS</varname></term> | |
| 905 | <term><varname>$XDG_DATA_HOME</varname></term> | |
| 906 | <term><varname>$XDG_DATA_DIRS</varname></term> | |
| 907 | ||
| af2d49f7 | 908 | <listitem><para>The systemd user |
| 7874bcd6 LP |
909 | manager uses these variables in |
| 910 | accordance to the <ulink | |
| 911 | url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG | |
| 912 | Base Directory specification</ulink> | |
| 913 | to find its configuration.</para></listitem> | |
| 914 | </varlistentry> | |
| 915 | ||
| 916 | <varlistentry> | |
| 917 | <term><varname>$SYSTEMD_UNIT_PATH</varname></term> | |
| 918 | ||
| 919 | <listitem><para>Controls where systemd | |
| 920 | looks for unit | |
| 921 | files.</para></listitem> | |
| 922 | </varlistentry> | |
| 923 | ||
| 924 | <varlistentry> | |
| 925 | <term><varname>$SYSTEMD_SYSVINIT_PATH</varname></term> | |
| 926 | ||
| 927 | <listitem><para>Controls where systemd | |
| 928 | looks for SysV init scripts.</para></listitem> | |
| 929 | </varlistentry> | |
| 930 | ||
| 931 | <varlistentry> | |
| 932 | <term><varname>$SYSTEMD_SYSVRCND_PATH</varname></term> | |
| 933 | ||
| 934 | <listitem><para>Controls where systemd | |
| 935 | looks for SysV init script runlevel link | |
| 936 | farms.</para></listitem> | |
| 937 | </varlistentry> | |
| 938 | ||
| 939 | <varlistentry> | |
| 940 | <term><varname>$LISTEN_PID</varname></term> | |
| 941 | <term><varname>$LISTEN_FDS</varname></term> | |
| 942 | ||
| 943 | <listitem><para>Set by systemd for | |
| 944 | supervised processes during | |
| 945 | socket-based activation. See | |
| 946 | <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
| 947 | for more information. | |
| 948 | </para></listitem> | |
| 949 | </varlistentry> | |
| 950 | ||
| 951 | <varlistentry> | |
| 952 | <term><varname>$NOTIFY_SOCKET</varname></term> | |
| 953 | ||
| 954 | <listitem><para>Set by systemd for | |
| 955 | supervised processes for status and | |
| 956 | start-up completion notification. See | |
| 957 | <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
| 958 | for more information. | |
| 959 | </para></listitem> | |
| 960 | </varlistentry> | |
| 961 | </variablelist> | |
| 962 | </refsect1> | |
| 160cd5c9 | 963 | |
| f3e219a2 LP |
964 | <refsect1> |
| 965 | <title>Kernel Command Line</title> | |
| 966 | ||
| 45dc3a04 LP |
967 | <para>When run as system instance systemd parses a |
| 968 | number of kernel command line | |
| 969 | arguments<footnote><para>If run inside a Linux | |
| 970 | container these arguments may be passed as command | |
| 971 | line arguments to systemd itself, next to any of the | |
| 972 | command line options listed in the Options section | |
| 973 | above. If run outside of Linux containers, these | |
| 974 | arguments are parsed from | |
| 975 | <filename>/proc/cmdline</filename> | |
| 976 | instead.</para></footnote>:</para> | |
| f3e219a2 | 977 | |
| ccc9a4f9 | 978 | <variablelist class='kernel-commandline-options'> |
| f3e219a2 LP |
979 | <varlistentry> |
| 980 | <term><varname>systemd.unit=</varname></term> | |
| c66e7bc7 | 981 | <term><varname>rd.systemd.unit=</varname></term> |
| f3e219a2 LP |
982 | |
| 983 | <listitem><para>Overrides the unit to | |
| 984 | activate on boot. Defaults to | |
| 985 | <filename>default.target</filename>. This | |
| 986 | may be used to temporarily boot into a | |
| 987 | different boot unit, for example | |
| 988 | <filename>rescue.target</filename> or | |
| 989 | <filename>emergency.service</filename>. See | |
| 990 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
| c66e7bc7 LP |
991 | for details about these units. The |
| 992 | option prefixed with | |
| bb31a4ac | 993 | <literal>rd.</literal> is honored |
| c66e7bc7 | 994 | only in the initial RAM disk (initrd), |
| 6b4991cf | 995 | while the one that is not prefixed only |
| c66e7bc7 | 996 | in the main system.</para></listitem> |
| f3e219a2 LP |
997 | </varlistentry> |
| 998 | ||
| f3e219a2 LP |
999 | <varlistentry> |
| 1000 | <term><varname>systemd.dump_core=</varname></term> | |
| 1001 | ||
| 1002 | <listitem><para>Takes a boolean | |
| 79640424 | 1003 | argument. If <option>true</option>, |
| f3e219a2 | 1004 | systemd dumps core when it |
| 79640424 | 1005 | crashes. Otherwise, no core dump is |
| f3e219a2 LP |
1006 | created. Defaults to |
| 1007 | <option>true</option>.</para></listitem> | |
| 1008 | </varlistentry> | |
| 1009 | ||
| 1010 | <varlistentry> | |
| 1011 | <term><varname>systemd.crash_shell=</varname></term> | |
| 1012 | ||
| 1013 | <listitem><para>Takes a boolean | |
| 79640424 | 1014 | argument. If <option>true</option>, |
| f3e219a2 | 1015 | systemd spawns a shell when it |
| 79640424 | 1016 | crashes. Otherwise, no shell is |
| f8553ccb | 1017 | spawned. Defaults to |
| f3e219a2 LP |
1018 | <option>false</option>, for security |
| 1019 | reasons, as the shell is not protected | |
| 1020 | by any password | |
| 1021 | authentication.</para></listitem> | |
| 1022 | </varlistentry> | |
| 1023 | ||
| 1024 | <varlistentry> | |
| 1025 | <term><varname>systemd.crash_chvt=</varname></term> | |
| 1026 | ||
| 1027 | <listitem><para>Takes an integer | |
| 1028 | argument. If positive systemd | |
| 1029 | activates the specified virtual | |
| 1030 | terminal when it crashes. Defaults to | |
| 74d00578 | 1031 | <constant>-1</constant>.</para></listitem> |
| f3e219a2 LP |
1032 | </varlistentry> |
| 1033 | ||
| 69dd2852 LP |
1034 | <varlistentry> |
| 1035 | <term><varname>systemd.confirm_spawn=</varname></term> | |
| 1036 | ||
| 1037 | <listitem><para>Takes a boolean | |
| 79640424 | 1038 | argument. If <option>true</option>, |
| 69dd2852 LP |
1039 | asks for confirmation when spawning |
| 1040 | processes. Defaults to | |
| 1041 | <option>false</option>.</para></listitem> | |
| 1042 | </varlistentry> | |
| 1043 | ||
| f3e219a2 LP |
1044 | <varlistentry> |
| 1045 | <term><varname>systemd.show_status=</varname></term> | |
| 1046 | ||
| 1047 | <listitem><para>Takes a boolean | |
| d450b6f2 ZJS |
1048 | argument or the constant |
| 1049 | <constant>auto</constant>. If | |
| 1050 | <option>true</option>, shows terse | |
| 1051 | service status updates on the console | |
| 1052 | during bootup. | |
| 1053 | <constant>auto</constant> behaves like | |
| 1054 | <option>false</option> until a service | |
| 1055 | fails or there is a significant delay | |
| 1056 | in boot. Defaults to | |
| c66e7bc7 LP |
1057 | <option>true</option>, unless |
| 1058 | <option>quiet</option> is passed as | |
| 1059 | kernel command line option in which | |
| 1060 | case it defaults to | |
| d450b6f2 | 1061 | <constant>auto</constant>.</para></listitem> |
| f3e219a2 LP |
1062 | </varlistentry> |
| 1063 | ||
| 69dd2852 LP |
1064 | <varlistentry> |
| 1065 | <term><varname>systemd.log_target=</varname></term> | |
| 1066 | <term><varname>systemd.log_level=</varname></term> | |
| 1067 | <term><varname>systemd.log_color=</varname></term> | |
| 1068 | <term><varname>systemd.log_location=</varname></term> | |
| 1069 | ||
| 1070 | <listitem><para>Controls log output, | |
| 1071 | with the same effect as the | |
| 1072 | <varname>$SYSTEMD_LOG_TARGET</varname>, <varname>$SYSTEMD_LOG_LEVEL</varname>, <varname>$SYSTEMD_LOG_COLOR</varname>, <varname>$SYSTEMD_LOG_LOCATION</varname> | |
| 1073 | environment variables described above.</para></listitem> | |
| 1074 | </varlistentry> | |
| 1075 | ||
| 0a494f1f LP |
1076 | <varlistentry> |
| 1077 | <term><varname>systemd.default_standard_output=</varname></term> | |
| 1078 | <term><varname>systemd.default_standard_error=</varname></term> | |
| 1079 | <listitem><para>Controls default | |
| 16dad32e | 1080 | standard output and error output for |
| 0a494f1f LP |
1081 | services, with the same effect as the |
| 1082 | <option>--default-standard-output=</option> | |
| 16dad32e | 1083 | and <option>--default-standard-error=</option> |
| 0a494f1f | 1084 | command line arguments described |
| 16dad32e | 1085 | above, respectively.</para></listitem> |
| 0a494f1f LP |
1086 | </varlistentry> |
| 1087 | ||
| aa704ba8 LP |
1088 | <varlistentry> |
| 1089 | <term><varname>systemd.setenv=</varname></term> | |
| 1090 | ||
| 1091 | <listitem><para>Takes a string | |
| e21fea24 KS |
1092 | argument in the form VARIABLE=VALUE. |
| 1093 | May be used to set default environment | |
| 1094 | variables to add to forked child processes. | |
| 1095 | May be used more than once to set multiple | |
| 1096 | variables.</para></listitem> | |
| aa704ba8 LP |
1097 | </varlistentry> |
| 1098 | ||
| c66e7bc7 LP |
1099 | <varlistentry> |
| 1100 | <term><varname>quiet</varname></term> | |
| 1101 | ||
| 9749cd77 | 1102 | <listitem><para>Turn off |
| d081dffb | 1103 | status output at boot, much like |
| c66e7bc7 | 1104 | <varname>systemd.show_status=false</varname> |
| c66e7bc7 LP |
1105 | would. Note that this option is also |
| 1106 | read by the kernel itself and disables | |
| 9749cd77 LN |
1107 | kernel log output. Passing this option |
| 1108 | hence turns off the usual output from | |
| 1109 | both the system manager and the kernel. | |
| 1110 | </para></listitem> | |
| 1111 | </varlistentry> | |
| 1112 | ||
| 1113 | <varlistentry> | |
| 1114 | <term><varname>debug</varname></term> | |
| 1115 | ||
| 1116 | <listitem><para>Turn on debugging | |
| 1117 | output. This is equivalent to | |
| 1118 | <varname>systemd.log_level=debug</varname>. | |
| 1119 | Note that this option is also read by | |
| 1120 | the kernel itself and enables kernel | |
| 1121 | debug output. Passing this option | |
| 1122 | hence turns on the debug output from | |
| 1123 | both the system manager and the | |
| c66e7bc7 LP |
1124 | kernel.</para></listitem> |
| 1125 | </varlistentry> | |
| 1126 | ||
| 1127 | <varlistentry> | |
| 77565771 | 1128 | <term><varname>-b</varname></term> |
| c66e7bc7 LP |
1129 | <term><varname>emergency</varname></term> |
| 1130 | ||
| 1131 | <listitem><para>Boot into emergency | |
| 1132 | mode. This is equivalent to | |
| 1133 | <varname>systemd.unit=emergency.target</varname> | |
| 1134 | and provided for compatibility | |
| 1135 | reasons and to be easier to type.</para></listitem> | |
| 1136 | </varlistentry> | |
| 1137 | ||
| 1138 | <varlistentry> | |
| 1139 | <term><varname>single</varname></term> | |
| 1140 | <term><varname>s</varname></term> | |
| 1141 | <term><varname>S</varname></term> | |
| 1142 | <term><varname>1</varname></term> | |
| 1143 | ||
| 1144 | <listitem><para>Boot into rescue | |
| 1145 | mode. This is equivalent to | |
| 1146 | <varname>systemd.unit=rescue.target</varname> | |
| 1147 | and provided for compatibility reasons | |
| 1148 | and to be easier to | |
| 1149 | type.</para></listitem> | |
| 1150 | </varlistentry> | |
| 1151 | ||
| 1152 | <varlistentry> | |
| 1153 | <term><varname>2</varname></term> | |
| 1154 | <term><varname>3</varname></term> | |
| 1155 | <term><varname>4</varname></term> | |
| 1156 | <term><varname>5</varname></term> | |
| 1157 | ||
| 1158 | <listitem><para>Boot into the | |
| 16dad32e AE |
1159 | specified legacy SysV runlevel. These |
| 1160 | are equivalent to | |
| c66e7bc7 LP |
1161 | <varname>systemd.unit=runlevel2.target</varname>, |
| 1162 | <varname>systemd.unit=runlevel3.target</varname>, | |
| 1163 | <varname>systemd.unit=runlevel4.target</varname>, | |
| 16dad32e | 1164 | and <varname>systemd.unit=runlevel5.target</varname>, respectively, |
| c66e7bc7 LP |
1165 | and provided for compatibility reasons |
| 1166 | and to be easier to | |
| 1167 | type.</para></listitem> | |
| 1168 | </varlistentry> | |
| 1169 | ||
| 1170 | <varlistentry> | |
| 1171 | <term><varname>locale.LANG=</varname></term> | |
| 1172 | <term><varname>locale.LANGUAGE=</varname></term> | |
| 1173 | <term><varname>locale.LC_CTYPE=</varname></term> | |
| 1174 | <term><varname>locale.LC_NUMERIC=</varname></term> | |
| 1175 | <term><varname>locale.LC_TIME=</varname></term> | |
| 1176 | <term><varname>locale.LC_COLLATE=</varname></term> | |
| 1177 | <term><varname>locale.LC_MONETARY=</varname></term> | |
| 1178 | <term><varname>locale.LC_MESSAGES=</varname></term> | |
| 1179 | <term><varname>locale.LC_PAPER=</varname></term> | |
| 1180 | <term><varname>locale.LC_NAME=</varname></term> | |
| 1181 | <term><varname>locale.LC_ADDRESS=</varname></term> | |
| 1182 | <term><varname>locale.LC_TELEPHONE=</varname></term> | |
| 1183 | <term><varname>locale.LC_MEASUREMENT=</varname></term> | |
| 1184 | <term><varname>locale.LC_IDENTIFICATION=</varname></term> | |
| 1185 | ||
| 1186 | <listitem><para>Set the system locale | |
| 1187 | to use. This overrides the settings in | |
| 1188 | <filename>/etc/locale.conf</filename>. For | |
| 1189 | more information see | |
| 1190 | <citerefentry><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
| 1191 | and | |
| 1192 | <citerefentry><refentrytitle>locale</refentrytitle><manvolnum>7</manvolnum></citerefentry>. | |
| 1193 | </para></listitem> | |
| 1194 | </varlistentry> | |
| f3e219a2 | 1195 | </variablelist> |
| c66e7bc7 LP |
1196 | |
| 1197 | <para>For other kernel command line parameters | |
| 1198 | understood by components of the core OS, please refer | |
| 1199 | to | |
| 1200 | <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> | |
| f3e219a2 LP |
1201 | </refsect1> |
| 1202 | ||
| 2218198b LP |
1203 | <refsect1> |
| 1204 | <title>Sockets and FIFOs</title> | |
| 1205 | ||
| 1206 | <variablelist> | |
| 1207 | <varlistentry> | |
| bb29785e | 1208 | <term><filename>/run/systemd/notify</filename></term> |
| 2218198b LP |
1209 | |
| 1210 | <listitem><para>Daemon status | |
| bb29785e | 1211 | notification socket. This is an |
| 74d00578 | 1212 | <constant>AF_UNIX</constant> datagram socket and is used to |
| bb29785e LP |
1213 | implement the daemon notification |
| 1214 | logic as implemented by | |
| 2218198b LP |
1215 | <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem> |
| 1216 | ||
| 1217 | </varlistentry> | |
| 1218 | ||
| 5dc50792 | 1219 | <varlistentry> |
| bb29785e | 1220 | <term><filename>/run/systemd/shutdownd</filename></term> |
| 5dc50792 LP |
1221 | |
| 1222 | <listitem><para>Used internally by the | |
| 1223 | <citerefentry><refentrytitle>shutdown</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
| 1224 | tool to implement delayed | |
| 74d00578 | 1225 | shutdowns. This is an <constant>AF_UNIX</constant> datagram |
| bb29785e | 1226 | socket.</para></listitem> |
| 5dc50792 LP |
1227 | </varlistentry> |
| 1228 | ||
| 2218198b | 1229 | <varlistentry> |
| bb29785e | 1230 | <term><filename>/run/systemd/private</filename></term> |
| 2218198b LP |
1231 | |
| 1232 | <listitem><para>Used internally as | |
| 1233 | communication channel between | |
| 1234 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
| 1235 | and the systemd process. This is an | |
| 74d00578 | 1236 | <constant>AF_UNIX</constant> stream socket. This interface |
| bb29785e LP |
1237 | is private to systemd and should not |
| 1238 | be used in external | |
| 2218198b LP |
1239 | projects.</para></listitem> |
| 1240 | </varlistentry> | |
| 1241 | ||
| 1242 | <varlistentry> | |
| 1243 | <term><filename>/dev/initctl</filename></term> | |
| 1244 | ||
| 1245 | <listitem><para>Limited compatibility | |
| 1246 | support for the SysV client interface, | |
| 1247 | as implemented by the | |
| 1248 | <filename>systemd-initctl.service</filename> | |
| 1249 | unit. This is a named pipe in the file | |
| 1250 | system. This interface is obsolete and | |
| 1251 | should not be used in new | |
| 1252 | applications.</para></listitem> | |
| 1253 | </varlistentry> | |
| 1254 | </variablelist> | |
| 9e632bf7 LP |
1255 | </refsect1> |
| 1256 | ||
| 9e632bf7 LP |
1257 | <refsect1> |
| 1258 | <title>See Also</title> | |
| 1259 | <para> | |
| ba54bcb8 | 1260 | The <ulink url="http://www.freedesktop.org/wiki/Software/systemd/">systemd Homepage</ulink>, |
| 5f9cfd4c | 1261 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| 4aa6e778 | 1262 | <citerefentry><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| 7874bcd6 | 1263 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| 1638bd34 | 1264 | <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| 7874bcd6 | 1265 | <citerefentry><refentrytitle>systemd-notify</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| 9e632bf7 | 1266 | <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
| cb07866b | 1267 | <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| 7874bcd6 LP |
1268 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| 1269 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
| 5aded369 | 1270 | <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| 013d8a39 | 1271 | <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
| 5aded369 | 1272 | <citerefentry project='man-pages'><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
| 9cc2c8b7 | 1273 | <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
| 9e632bf7 LP |
1274 | </para> |
| 1275 | </refsect1> | |
| 1276 | ||
| 1277 | </refentry> |