man/systemd.special.xml

   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
  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
  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
  18   Lesser General Public License for more details.
  19
  20   You should have received a copy of the GNU Lesser General Public License
  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  22 -->
  23
  24 <refentry id="systemd.special">
  25
  26         <refentryinfo>
  27                 <title>systemd.special</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>systemd.special</refentrytitle>
  42                 <manvolnum>7</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>systemd.special</refname>
  47                 <refpurpose>Special systemd units</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <para><filename>basic.target</filename>,
  52                 <filename>bluetooth.target</filename>,
  53                 <filename>ctrl-alt-del.target</filename>,
  54                 <filename>cryptsetup.target</filename>,
  55                 <filename>dbus.service</filename>,
  56                 <filename>dbus.socket</filename>,
  57                 <filename>default.target</filename>,
  58                 <filename>display-manager.service</filename>,
  59                 <filename>emergency.target</filename>,
  60                 <filename>exit.target</filename>,
  61                 <filename>final.target</filename>,
  62                 <filename>getty.target</filename>,
  63                 <filename>graphical.target</filename>,
  64                 <filename>hibernate.target</filename>,
  65                 <filename>http-daemon.target</filename>,
  66                 <filename>halt.target</filename>,
  67                 <filename>kbrequest.target</filename>,
  68                 <filename>kexec.target</filename>,
  69                 <filename>local-fs.target</filename>,
  70                 <filename>local-fs-pre.target</filename>,
  71                 <filename>mail-transfer-agent.target</filename>,
  72                 <filename>multi-user.target</filename>,
  73                 <filename>network.target</filename>,
  74                 <filename>nss-lookup.target</filename>,
  75                 <filename>nss-user-lookup.target</filename>,
  76                 <filename>poweroff.target</filename>,
  77                 <filename>printer.target</filename>,
  78                 <filename>reboot.target</filename>,
  79                 <filename>remote-fs.target</filename>,
  80                 <filename>remote-fs-pre.target</filename>,
  81                 <filename>rescue.target</filename>,
  82                 <filename>rpcbind.target</filename>,
  83                 <filename>runlevel2.target</filename>,
  84                 <filename>runlevel3.target</filename>,
  85                 <filename>runlevel4.target</filename>,
  86                 <filename>runlevel5.target</filename>,
  87                 <filename>shutdown.target</filename>,
  88                 <filename>sigpwr.target</filename>,
  89                 <filename>sleep.target</filename>,
  90                 <filename>smartcard.target</filename>,
  91                 <filename>sockets.target</filename>,
  92                 <filename>sound.target</filename>,
  93                 <filename>suspend.target</filename>,
  94                 <filename>swap.target</filename>,
  95                 <filename>sysinit.target</filename>,
  96                 <filename>syslog.service</filename>,
  97                 <filename>syslog.socket</filename>,
  98                 <filename>syslog.target</filename>,
  99                 <filename>system-update.target</filename>,
 100                 <filename>time-sync.target</filename>,
 101                 <filename>umount.target</filename></para>
 102         </refsynopsisdiv>
 103
 104         <refsect1>
 105                 <title>Description</title>
 106
 107                 <para>A few units are treated specially by
 108                 systemd. They have special internal semantics and
 109                 cannot be renamed.</para>
 110         </refsect1>
 111
 112         <refsect1>
 113                 <title>Special System Units</title>
 114
 115                 <variablelist>
 116                         <varlistentry>
 117                                 <term><filename>basic.target</filename></term>
 118                                 <listitem>
 119                                         <para>A special target unit
 120                                         covering early boot-up.</para>
 121                                         <para>systemd automatically
 122                                         adds dependencies of the types
 123                                         Requires and After for this
 124                                         target unit to all SysV
 125                                         service units configured for
 126                                         runlevel 1 to 5.</para>
 127                                         <para>Usually this should pull-in
 128                                         all sockets, mount points,
 129                                         swap devices and other basic
 130                                         initialization necessary for
 131                                         the general purpose
 132                                         daemons. Most normal daemons
 133                                         should have dependencies of
 134                                         type After and Requires on
 135                                         this unit.</para>
 136                                 </listitem>
 137                         </varlistentry>
 138                         <varlistentry>
 139                                 <term><filename>bluetooth.target</filename></term>
 140                                 <listitem>
 141                                         <para>This target is started
 142                                         automatically as soon as a
 143                                         bluetooth controller is
 144                                         plugged in or becomes
 145                                         available at boot.</para>
 146                                 </listitem>
 147                         </varlistentry>
 148                         <varlistentry>
 149                                 <term><filename>ctrl-alt-del.target</filename></term>
 150                                 <listitem>
 151                                         <para>systemd starts this
 152                                         target whenever
 153                                         Control+Alt+Del is pressed on
 154                                         the console. Usually this
 155                                         should be aliased (symlinked)
 156                                         to
 157                                         <filename>reboot.target</filename>.</para>
 158                                 </listitem>
 159                         </varlistentry>
 160                         <varlistentry>
 161                                 <term><filename>cryptsetup.target</filename></term>
 162                                 <listitem>
 163                                         <para>A target that pulls in
 164                                         setup services for all
 165                                         encrypted block
 166                                         devices.</para>
 167                                 </listitem>
 168                         </varlistentry>
 169                         <varlistentry>
 170                                 <term><filename>dbus.service</filename></term>
 171                                 <listitem>
 172                                         <para>A special unit for the
 173                                         D-Bus system bus. As soon as
 174                                         this service is fully started
 175                                         up systemd will connect to it
 176                                         and register its
 177                                         service.</para>
 178                                 </listitem>
 179                         </varlistentry>
 180                         <varlistentry>
 181                                 <term><filename>dbus.socket</filename></term>
 182                                 <listitem>
 183                                         <para>A special unit for the
 184                                         D-Bus system bus socket. All
 185                                         units with
 186                                         <literal>Type=dbus</literal>
 187                                         automatically gain a
 188                                         dependency on this
 189                                         unit.</para>
 190                                 </listitem>
 191                         </varlistentry>
 192                         <varlistentry>
 193                                 <term><filename>default.target</filename></term>
 194                                 <listitem>
 195                                         <para>The default unit systemd
 196                                         starts at bootup. Usually this
 197                                         should be aliased (symlinked)
 198                                         to
 199                                         <filename>multi-user.target</filename>
 200                                         or
 201                                         <filename>graphical.target</filename>.</para>
 202                                         <para>The default unit systemd
 203                                         starts at bootup can be
 204                                         overridden with the
 205                                         <varname>systemd.unit=</varname>
 206                                         kernel command line option.</para>
 207                                 </listitem>
 208                         </varlistentry>
 209                         <varlistentry>
 210                                 <term><filename>display-manager.service</filename></term>
 211                                 <listitem>
 212                                         <para>The display manager
 213                                         service. Usually this should
 214                                         be aliased (symlinked) to
 215                                         <filename>gdm.service</filename>
 216                                         or a similar display manager
 217                                         service.</para>
 218                                         <para>systemd automatically
 219                                         adds dependencies of type
 220                                         After for this target unit to
 221                                         all SysV init script service
 222                                         units with a LSB header
 223                                         referring to the
 224                                         <literal>$x-display-manager</literal>
 225                                         facility, for compatibility
 226                                         with Debian.</para>
 227                                 </listitem>
 228                         </varlistentry>
 229                         <varlistentry>
 230                                 <term><filename>emergency.target</filename></term>
 231                                 <listitem>
 232                                         <para>A special target unit
 233                                         that starts an emergency
 234                                         shell on the main
 235                                         console. This unit is supposed
 236                                         to be used with the kernel
 237                                         command line option
 238                                         <varname>systemd.unit=</varname>
 239                                         and has otherwise little use.
 240                                         </para>
 241                                 </listitem>
 242                         </varlistentry>
 243                         <varlistentry>
 244                                 <term><filename>final.target</filename></term>
 245                                 <listitem>
 246                                         <para>A special target unit
 247                                         that is used during the
 248                                         shutdown logic and may be used
 249                                         to pull in late services after
 250                                         all normal services are
 251                                         already terminated and all
 252                                         mounts unmounted.
 253                                         </para>
 254                                 </listitem>
 255                         </varlistentry>
 256                         <varlistentry>
 257                                 <term><filename>getty.target</filename></term>
 258                                 <listitem>
 259                                         <para>A special target unit
 260                                         that pulls in all local TTY
 261                                         <filename>getty</filename> instances.
 262                                         </para>
 263                                 </listitem>
 264                         </varlistentry>
 265                         <varlistentry>
 266                                 <term><filename>graphical.target</filename></term>
 267                                 <listitem>
 268                                         <para>A special target unit
 269                                         for setting up a graphical
 270                                         login screen. This pulls in
 271                                         <filename>multi-user.target</filename>.</para>
 272
 273                                         <para>Units that are needed
 274                                         for graphical login shall add
 275                                         Wants dependencies for their
 276                                         unit to this unit (or
 277                                         <filename>multi-user.target</filename>)
 278                                         during installation.</para>
 279                                 </listitem>
 280                         </varlistentry>
 281                         <varlistentry>
 282                                 <term><filename>hibernate.target</filename></term>
 283                                 <listitem>
 284                                         <para>A special target unit
 285                                         for hibernating the
 286                                         system. This pulls in
 287                                         <filename>sleep.target</filename>.</para>
 288                                 </listitem>
 289                         </varlistentry>
 290                         <varlistentry>
 291                                 <term><filename>http-daemon.target</filename></term>
 292                                 <listitem>
 293                                         <para>A target for pulling in
 294                                         an HTTP server if there is
 295                                         any.</para>
 296                                         <para>systemd automatically
 297                                         adds dependencies of type
 298                                         After for this target unit to
 299                                         all SysV init script service
 300                                         units with a LSB header
 301                                         referring to the
 302                                         <literal>$httpd</literal>
 303                                         facility.</para>
 304                                 </listitem>
 305                         </varlistentry>
 306                         <varlistentry>
 307                                 <term><filename>halt.target</filename></term>
 308                                 <listitem>
 309                                         <para>A special target unit
 310                                         for shutting down and halting the system.</para>
 311
 312                                         <para>Applications wanting to
 313                                         halt the system should start
 314                                         this unit.</para>
 315                                 </listitem>
 316                         </varlistentry>
 317                         <varlistentry>
 318                                 <term><filename>kbrequest.target</filename></term>
 319                                 <listitem>
 320                                         <para>systemd starts this
 321                                         target whenever Alt+ArrowUp is
 322                                         pressed on the console. This
 323                                         is a good candidate to be
 324                                         aliased (symlinked) to
 325                                         <filename>rescue.target</filename>.</para>
 326                                 </listitem>
 327                         </varlistentry>
 328                         <varlistentry>
 329                                 <term><filename>kexec.target</filename></term>
 330                                 <listitem>
 331                                         <para>A special target unit
 332                                         for shutting down and rebooting the system via kexec.</para>
 333
 334                                         <para>Applications wanting to
 335                                         reboot the system with kexec should start
 336                                         this unit.</para>
 337                                 </listitem>
 338                         </varlistentry>
 339                         <varlistentry>
 340                                 <term><filename>local-fs.target</filename></term>
 341                                 <listitem>
 342                                         <para>systemd automatically
 343                                         adds dependencies of type
 344                                         After to all mount units that
 345                                         refer to local mount points
 346                                         for this target unit. In
 347                                         addition, systemd adds
 348                                         dependencies of type Wants to
 349                                         this target unit for those
 350                                         mounts listed in
 351                                         <filename>/etc/fstab</filename>
 352                                         that have the
 353                                         <option>auto</option> and
 354                                         <option>comment=systemd.mount</option>
 355                                         mount options set.</para>
 356
 357                                         <para>systemd automatically
 358                                         adds dependencies of type
 359                                         After for this target unit to
 360                                         all SysV init script service
 361                                         units with an LSB header
 362                                         referring to the
 363                                         <literal>$local_fs</literal>
 364                                         facility.</para>
 365                                 </listitem>
 366                         </varlistentry>
 367                         <varlistentry>
 368                                 <term><filename>local-fs-pre.target</filename></term>
 369                                 <listitem>
 370                                         <para>This target unit is
 371                                         automatically ordered before
 372                                         all local mount points marked
 373                                         with <option>auto</option>
 374                                         (see above). It can be used to
 375                                         execute certain units before
 376                                         all local mounts.</para>
 377                                 </listitem>
 378                         </varlistentry>
 379                         <varlistentry>
 380                                 <term><filename>mail-transfer-agent.target</filename></term>
 381                                 <listitem>
 382                                         <para>The mail transfer agent
 383                                         (MTA) service. Usually this
 384                                         should pull-in all units
 385                                         necessary for
 386                                         sending/receiving mails on the
 387                                         local host.</para>
 388
 389                                         <para>systemd automatically
 390                                         adds dependencies of type
 391                                         After for this target unit to
 392                                         all SysV init script service
 393                                         units with an LSB header
 394                                         referring to the
 395                                         <literal>$mail-transfer-agent</literal>
 396                                         or
 397                                         <literal>$mail-transport-agent</literal>
 398                                         facilities, for compatibility
 399                                         with Debian.</para>
 400                                 </listitem>
 401                         </varlistentry>
 402                         <varlistentry>
 403                                 <term><filename>multi-user.target</filename></term>
 404                                 <listitem>
 405                                         <para>A special target unit
 406                                         for setting up a multi-user
 407                                         system (non-graphical). This
 408                                         is pulled in by
 409                                         <filename>graphical.target</filename>.</para>
 410
 411                                         <para>Units that are needed
 412                                         for a multi-user system shall
 413                                         add Wants dependencies to
 414                                         this unit for their unit during
 415                                         installation.</para>
 416                                 </listitem>
 417                         </varlistentry>
 418                         <varlistentry>
 419                                 <term><filename>network.target</filename></term>
 420                                 <listitem>
 421                                         <para>systemd automatically
 422                                         adds dependencies of type
 423                                         After for this target unit to
 424                                         all SysV init script service
 425                                         units with an LSB header
 426                                         referring to the
 427                                         <literal>$network</literal>
 428                                         facility.</para>
 429                                 </listitem>
 430                         </varlistentry>
 431                         <varlistentry>
 432                                 <term><filename>nss-lookup.target</filename></term>
 433                                 <listitem>
 434                                         <para>A target that should be
 435                                         used as synchronization point
 436                                         for all host/network name
 437                                         service lookups. Note that
 438                                         this is independent of
 439                                         user/group name lookups for
 440                                         which
 441                                         <filename>nss-user-lookup.target</filename>
 442                                         should be used. systemd
 443                                         automatically adds
 444                                         dependencies of type After for
 445                                         this target unit to all SysV
 446                                         init script service units with
 447                                         an LSB header referring to the
 448                                         <literal>$named</literal>
 449                                         facility.</para>
 450                                 </listitem>
 451                         </varlistentry>
 452                         <varlistentry>
 453                                 <term><filename>nss-user-lookup.target</filename></term>
 454                                 <listitem>
 455                                         <para>A target that should be
 456                                         used as synchronization point
 457                                         for all user/group name
 458                                         service lookups. Note that
 459                                         this is independent of
 460                                         host/network name lookups for
 461                                         which
 462                                         <filename>nss-lookup.target</filename>
 463                                         should be used. </para>
 464                                 </listitem>
 465                         </varlistentry>
 466                         <varlistentry>
 467                                 <term><filename>poweroff.target</filename></term>
 468                                 <listitem>
 469                                         <para>A special target unit
 470                                         for shutting down and powering off the system.</para>
 471
 472                                         <para>Applications wanting to
 473                                         power off the system should start
 474                                         this unit.</para>
 475
 476                                         <para><filename>runlevel0.target</filename>
 477                                         is an alias for this target
 478                                         unit, for compatibility with SysV.</para>
 479                                 </listitem>
 480                         </varlistentry>
 481                         <varlistentry>
 482                                 <term><filename>printer.target</filename></term>
 483                                 <listitem>
 484                                         <para>This target is started
 485                                         automatically as soon as a
 486                                         printer is plugged in or
 487                                         becomes available at
 488                                         boot.</para>
 489                                 </listitem>
 490                         </varlistentry>
 491                         <varlistentry>
 492                                 <term><filename>reboot.target</filename></term>
 493                                 <listitem>
 494                                         <para>A special target unit
 495                                         for shutting down and rebooting the system.</para>
 496
 497                                         <para>Applications wanting to
 498                                         reboot the system should start
 499                                         this unit.</para>
 500
 501                                         <para><filename>runlevel6.target</filename>
 502                                         is an alias for this target
 503                                         unit, for compatibility with SysV.</para>
 504                                 </listitem>
 505                         </varlistentry>
 506                         <varlistentry>
 507                                 <term><filename>remote-fs.target</filename></term>
 508                                 <listitem>
 509                                         <para>Similar to
 510                                         <filename>local-fs.target</filename>,
 511                                         but for remote mount
 512                                         points.</para>
 513
 514                                         <para>systemd automatically
 515                                         adds dependencies of type
 516                                         After for this target unit to
 517                                         all SysV init script service
 518                                         units with an LSB header
 519                                         referring to the
 520                                         <literal>$remote_fs</literal>
 521                                         facility.</para>
 522                                 </listitem>
 523                         </varlistentry>
 524                         <varlistentry>
 525                                 <term><filename>remote-fs-pre.target</filename></term>
 526                                 <listitem>
 527                                         <para>This target unit is
 528                                         automatically ordered before
 529                                         all remote mount points marked
 530                                         with <option>auto</option>
 531                                         (see above). It can be used to
 532                                         execute certain units before
 533                                         all remote mounts.</para>
 534                                 </listitem>
 535                         </varlistentry>
 536                         <varlistentry>
 537                                 <term><filename>rescue.target</filename></term>
 538                                 <listitem>
 539                                         <para>A special target unit
 540                                         for setting up the base system
 541                                         and a rescue shell.</para>
 542
 543                                         <para><filename>runlevel1.target</filename>
 544                                         is an alias for this target
 545                                         unit, for compatibility with SysV.</para>
 546                                 </listitem>
 547                         </varlistentry>
 548                         <varlistentry>
 549                                 <term><filename>rpcbind.target</filename></term>
 550                                 <listitem>
 551                                         <para>systemd automatically
 552                                         adds dependencies of type
 553                                         After for this target unit to
 554                                         all SysV init script service
 555                                         units with an LSB header
 556                                         referring to the
 557                                         <literal>$rpcbind</literal>
 558                                         facility.</para>
 559                                 </listitem>
 560                         </varlistentry>
 561                         <varlistentry>
 562                                 <term><filename>runlevel2.target</filename></term>
 563                                 <listitem>
 564                                         <para>This is a target that is
 565                                         called whenever the SysV
 566                                         compatibility code asks for
 567                                         runlevel 2. It is a good idea
 568                                         to make this an alias for
 569                                         (i.e. symlink to)
 570                                         <filename>multi-user.target</filename>.</para>
 571                                 </listitem>
 572                         </varlistentry>
 573                         <varlistentry>
 574                                 <term><filename>runlevel3.target</filename></term>
 575                                 <listitem>
 576                                         <para>This is a target that is
 577                                         called whenever the SysV
 578                                         compatibility code asks for
 579                                         runlevel 3. It is a good idea
 580                                         to make this an alias for
 581                                         (i.e. symlink to)
 582                                         <filename>multi-user.target</filename>
 583                                         or
 584                                         <filename>graphical.target</filename>.</para>
 585                                 </listitem>
 586                         </varlistentry>
 587                         <varlistentry>
 588                                 <term><filename>runlevel4.target</filename></term>
 589                                 <listitem>
 590                                         <para>This is a target that is
 591                                         called whenever the SysV
 592                                         compatibility code asks for
 593                                         runlevel 4. It is a good idea
 594                                         to make this an alias for
 595                                         (i.e. symlink to)
 596                                         <filename>multi-user.target</filename>
 597                                         or
 598                                         <filename>graphical.target</filename>.</para>
 599                                 </listitem>
 600                         </varlistentry>
 601                         <varlistentry>
 602                                 <term><filename>runlevel5.target</filename></term>
 603                                 <listitem>
 604                                         <para>This is a target that is
 605                                         called whenever the SysV
 606                                         compatibility code asks for
 607                                         runlevel 5. It is a good idea
 608                                         to make this an alias for
 609                                         (i.e. symlink to)
 610                                         <filename>multi-user.target</filename>
 611                                         or
 612                                         <filename>graphical.target</filename>.</para>
 613                                 </listitem>
 614                         </varlistentry>
 615                         <varlistentry>
 616                                 <term><filename>shutdown.target</filename></term>
 617                                 <listitem>
 618                                         <para>A special target unit
 619                                         that terminates the services
 620                                         on system shutdown.</para>
 621
 622                                         <para>Services that shall be
 623                                         terminated on system shutdown
 624                                         shall add Conflicts
 625                                         dependencies to this unit for
 626                                         their service unit, which is
 627                                         implicitly done when
 628                                         <varname>DefaultDependencies=yes</varname>
 629                                         is set (the default).</para>
 630
 631                                         <para>systemd automatically
 632                                         adds dependencies of type
 633                                         Conflicts to this target unit
 634                                         for all SysV init script
 635                                         service units that shall be
 636                                         terminated in SysV runlevels 0
 637                                         or 6.</para>
 638                                 </listitem>
 639                         </varlistentry>
 640                         <varlistentry>
 641                                 <term><filename>sigpwr.target</filename></term>
 642                                 <listitem>
 643                                         <para>A special target that is
 644                                         started when systemd receives
 645                                         the SIGPWR process signal,
 646                                         which is normally sent by the
 647                                         kernel or UPS daemons when
 648                                         power fails.</para>
 649                                 </listitem>
 650                         </varlistentry>
 651                         <varlistentry>
 652                                 <term><filename>sleep.target</filename></term>
 653                                 <listitem>
 654                                         <para>A special target unit
 655                                         that is pulled in by
 656                                         <filename>suspend.target</filename>
 657                                         and
 658                                         <filename>hibernate.target</filename>
 659                                         and may be used to hook units
 660                                         into the sleep state
 661                                         logic.</para>
 662                                 </listitem>
 663                         </varlistentry>
 664                         <varlistentry>
 665                                 <term><filename>smartcard.target</filename></term>
 666                                 <listitem>
 667                                         <para>This target is started
 668                                         automatically as soon as a
 669                                         smartcard controller is
 670                                         plugged in or becomes
 671                                         available at boot.</para>
 672                                 </listitem>
 673                         </varlistentry>
 674                         <varlistentry>
 675                                 <term><filename>sockets.target</filename></term>
 676                                 <listitem>
 677                                         <para>A special target unit
 678                                         that sets up all service
 679                                         sockets.</para>
 680
 681                                         <para>Services that can be
 682                                         socket-activated shall add
 683                                         Wants dependencies to this
 684                                         unit for their socket unit
 685                                         during installation.</para>
 686                                 </listitem>
 687                         </varlistentry>
 688                         <varlistentry>
 689                                 <term><filename>sound.target</filename></term>
 690                                 <listitem>
 691                                         <para>This target is started
 692                                         automatically as soon as a
 693                                         sound card is plugged in or
 694                                         becomes available at
 695                                         boot.</para>
 696                                 </listitem>
 697                         </varlistentry>
 698                         <varlistentry>
 699                                 <term><filename>suspend.target</filename></term>
 700                                 <listitem>
 701                                         <para>A special target unit
 702                                         for suspending the
 703                                         system. This pulls in
 704                                         <filename>sleep.target</filename>.</para>
 705                                 </listitem>
 706                         </varlistentry>
 707                         <varlistentry>
 708                                 <term><filename>swap.target</filename></term>
 709                                 <listitem>
 710                                         <para>Similar to
 711                                         <filename>local-fs.target</filename>, but for swap
 712                                         partitions and swap
 713                                         files.</para>
 714                                 </listitem>
 715                         </varlistentry>
 716                         <varlistentry>
 717                                 <term><filename>sysinit.target</filename></term>
 718                                 <listitem>
 719                                         <para>A special target unit
 720                                         covering early boot-up scripts.</para>
 721                                         <para>systemd automatically
 722                                         adds dependencies of the types
 723                                         Wants and After for all
 724                                         SysV service units configured
 725                                         for runlevels that are not 0
 726                                         to 6 to this target unit.
 727                                         This covers the special
 728                                         boot-up runlevels some
 729                                         distributions have, such as S
 730                                         or b.</para>
 731                                 </listitem>
 732                         </varlistentry>
 733                         <varlistentry>
 734                                 <term><filename>syslog.service</filename></term>
 735                                 <listitem>
 736                                         <para>The syslog service if
 737                                         any. Implementations should
 738                                         create a symlink from the
 739                                         actual syslog implementation
 740                                         to this generic name for
 741                                         activating it.</para>
 742                                 </listitem>
 743                         </varlistentry>
 744                         <varlistentry>
 745                                 <term><filename>syslog.socket</filename></term>
 746                                 <listitem>
 747                                         <para>The socket unit where
 748                                         syslog implementations should
 749                                         listen on. All userspace log
 750                                         messages will be made
 751                                         available on this
 752                                         socket.</para>
 753                                 </listitem>
 754                         </varlistentry>
 755                         <varlistentry>
 756                                 <term><filename>syslog.target</filename></term>
 757                                 <listitem>
 758                                         <para>systemd automatically
 759                                         adds dependencies of type
 760                                         After for this target unit to
 761                                         all SysV init script service
 762                                         units with an LSB header
 763                                         referring to the
 764                                         <literal>$syslog</literal>
 765                                         facility.</para>
 766                                 </listitem>
 767                         </varlistentry>
 768                         <varlistentry>
 769                                 <term><filename>system-update.target</filename></term>
 770                                 <listitem>
 771                                         <para>A special target unit
 772                                         that is used for off-line
 773                                         system updates.
 774                                         <citerefentry><refentrytitle>systemd-system-update-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 775                                         will redirect the boot process
 776                                         to this target if
 777                                         <filename>/system-update</filename>
 778                                         exists. For more information
 779                                         see the <ulink
 780                                         url="http://freedesktop.org/wiki/Software/systemd/SystemUpdates">System
 781                                         Updates
 782                                         Specification</ulink>.</para>
 783                                 </listitem>
 784                         </varlistentry>
 785                         <varlistentry>
 786                                 <term><filename>time-sync.target</filename></term>
 787                                 <listitem>
 788                                         <para>systemd automatically
 789                                         adds dependencies of type
 790                                         After for this target unit to
 791                                         all SysV init script service
 792                                         units with an LSB header
 793                                         referring to the
 794                                         <literal>$time</literal>
 795                                         facility.</para>
 796                                 </listitem>
 797                         </varlistentry>
 798                         <varlistentry>
 799                                 <term><filename>umount.target</filename></term>
 800                                 <listitem>
 801                                         <para>A special target unit
 802                                         that umounts all mount and
 803                                         automount points on system
 804                                         shutdown.</para>
 805
 806                                         <para>Mounts that shall be
 807                                         unmounted on system shutdown
 808                                         shall add Conflicts
 809                                         dependencies to this unit for
 810                                         their mount unit, which is
 811                                         implicitly done when
 812                                         <varname>DefaultDependencies=yes</varname>
 813                                         is set (the default).</para>
 814                                 </listitem>
 815                         </varlistentry>
 816
 817                 </variablelist>
 818         </refsect1>
 819
 820         <refsect1>
 821                 <title>Special User Units</title>
 822
 823                 <para>When systemd runs as a user instance, the
 824                 following special units are available, which have
 825                 similar definitions as their system counterparts:
 826                 <filename>default.target</filename>,
 827                 <filename>shutdown.target</filename>,
 828                 <filename>sockets.target</filename></para>
 829
 830                 <para>In addition the following special unit is
 831                 understood only when systemd runs as service instance:</para>
 832
 833                 <variablelist>
 834                         <varlistentry>
 835                                 <term><filename>exit.target</filename></term>
 836                                 <listitem>
 837                                         <para>A special service unit
 838                                         for shutting down the
 839                                         user service manager.</para>
 840
 841                                         <para>Applications wanting to
 842                                         terminate the user service
 843                                         manager should start this
 844                                         unit. If systemd receives
 845                                         SIGTERM or SIGINT when running
 846                                         as user service daemon it will
 847                                         start this unit.</para>
 848
 849                                         <para>Normally, this pulls in
 850                                         <filename>shutdown.target</filename>
 851                                         which in turn should be
 852                                         conflicted by all units that
 853                                         want to be shut down on
 854                                         user service manager exit.</para>
 855                                 </listitem>
 856                         </varlistentry>
 857                 </variablelist>
 858         </refsect1>
 859
 860         <refsect1>
 861                   <title>See Also</title>
 862                   <para>
 863                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 864                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 865                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 866                           <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 867                           <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 868                           <citerefentry><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 869                   </para>
 870         </refsect1>
 871
 872 </refentry>