[thirdparty/systemd.git] / man / bootup.xml

<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<!--
  SPDX-License-Identifier: LGPL-2.1+

  This file is part of systemd.

  Copyright 2012 Lennart Poettering
-->

<refentry id="bootup">

  <refentryinfo>
    <title>bootup</title>
    <productname>systemd</productname>

    <authorgroup>
      <author>
        <contrib>Developer</contrib>
        <firstname>Lennart</firstname>
        <surname>Poettering</surname>
        <email>lennart@poettering.net</email>
      </author>
    </authorgroup>
  </refentryinfo>

  <refmeta>
    <refentrytitle>bootup</refentrytitle>
    <manvolnum>7</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>bootup</refname>
    <refpurpose>System bootup process</refpurpose>
  </refnamediv>

  <refsect1>
    <title>Description</title>

    <para>A number of different components are involved in the system
    boot. Immediately after power-up, the system BIOS will do minimal
    hardware initialization, and hand control over to a boot loader
    stored on a persistent storage device. This boot loader will then
    invoke an OS kernel from disk (or the network). In the Linux case,
    this kernel (optionally) extracts and executes an initial RAM disk
    image (initrd), such as generated by
    <citerefentry project='die-net'><refentrytitle>dracut</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
    which looks for the root file system (possibly using
    <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    for this). After the root file system is found and mounted, the
    initrd hands over control to the host's system manager (such as
    <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>)
    stored on the OS image, which is then responsible for probing all
    remaining hardware, mounting all necessary file systems and
    spawning all configured services.</para>

    <para>On shutdown, the system manager stops all services, unmounts
    all file systems (detaching the storage technologies backing
    them), and then (optionally) jumps back into the initrd code which
    unmounts/detaches the root file system and the storage it resides
    on. As a last step, the system is powered down.</para>

    <para>Additional information about the system boot process may be
    found in
    <citerefentry project='man-pages'><refentrytitle>boot</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
  </refsect1>

  <refsect1>
    <title>System Manager Bootup</title>

    <para>At boot, the system manager on the OS image is responsible
    for initializing the required file systems, services and drivers
    that are necessary for operation of the system. On
    <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    systems, this process is split up in various discrete steps which
    are exposed as target units. (See
    <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>
    for detailed information about target units.) The boot-up process
    is highly parallelized so that the order in which specific target
    units are reached is not deterministic, but still adheres to a
    limited amount of ordering structure.</para>

    <para>When systemd starts up the system, it will activate all
    units that are dependencies of <filename>default.target</filename>
    (as well as recursively all dependencies of these dependencies).
    Usually, <filename>default.target</filename> is simply an alias of
    <filename>graphical.target</filename> or
    <filename>multi-user.target</filename>, depending on whether the
    system is configured for a graphical UI or only for a text
    console. To enforce minimal ordering between the units pulled in,
    a number of well-known target units are available, as listed on
    <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>

    <para>The following chart is a structural overview of these
    well-known units and their position in the boot-up logic. The
    arrows describe which units are pulled in and ordered before which
    other units. Units near the top are started before units nearer to
    the bottom of the chart.</para>

    <!-- note: do not use unicode ellipsis here, because docbook will replace that
         with three dots anyway, messing up alignment -->
<programlisting>local-fs-pre.target
         |
         v
(various mounts and   (various swap   (various cryptsetup
 fsck services...)     devices...)        devices...)       (various low-level   (various low-level
         |                  |                  |             services: udevd,     API VFS mounts:
         v                  v                  v             tmpfiles, random     mqueue, configfs,
  local-fs.target      swap.target     cryptsetup.target    seed, sysctl, ...)      debugfs, ...)
         |                  |                  |                    |                    |
         \__________________|_________________ | ___________________|____________________/
                                              \|/
                                               v
                                        sysinit.target
                                               |
          ____________________________________/|\________________________________________
         /                  |                  |                    |                    \
         |                  |                  |                    |                    |
         v                  v                  |                    v                    v
     (various           (various               |                (various          rescue.service
    timers...)          paths...)              |               sockets...)               |
         |                  |                  |                    |                    v
         v                  v                  |                    v              <emphasis>rescue.target</emphasis>
   timers.target      paths.target             |             sockets.target
         |                  |                  |                    |
         v                  \_________________ | ___________________/
                                              \|/
                                               v
                                         basic.target
                                               |
          ____________________________________/|                                 emergency.service
         /                  |                  |                                         |
         |                  |                  |                                         v
         v                  v                  v                                 <emphasis>emergency.target</emphasis>
     display-        (various system    (various system
 manager.service         services           services)
         |             required for            |
         |            graphical UIs)           v
         |                  |           <emphasis>multi-user.target</emphasis>
         |                  |                  |
         \_________________ | _________________/
                           \|/
                            v
                  <emphasis>graphical.target</emphasis></programlisting>

    <para>Target units that are commonly used as boot targets are
    <emphasis>emphasized</emphasis>. These units are good choices as
    goal targets, for example by passing them to the
    <varname>systemd.unit=</varname> kernel command line option (see
    <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>)
    or by symlinking <filename>default.target</filename> to them.
    </para>

    <para><filename>timers.target</filename> is pulled-in by
    <filename>basic.target</filename> asynchronously. This allows
    timers units to depend on services which become only available
    later in boot.</para>
  </refsect1>

  <refsect1>
    <title>Bootup in the Initial RAM Disk (initrd)</title>
    <para>The initial RAM disk implementation (initrd) can be set up
    using systemd as well. In this case, boot up inside the initrd
    follows the following structure.</para>

    <para>The default target in the initrd is
    <filename>initrd.target</filename>. The bootup process begins
    identical to the system manager bootup (see above) until it
    reaches <filename>basic.target</filename>. From there, systemd
    approaches the special target <filename>initrd.target</filename>.

    Before any file systems are mounted, it must be determined whether
    the system will resume from hibernation or proceed with normal boot.
    This is accomplished by <filename>systemd-hibernate-resume@.service</filename>
    which must be finished before <filename>local-fs-pre.target</filename>,
    so no filesystems can be mounted before the check is complete.

    When the root device becomes available,
    <filename>initd-root-device.target</filename> is reached.
    If the root device can be mounted at
    <filename>/sysroot</filename>, the
    <filename>sysroot.mount</filename> unit becomes active and
    <filename>initrd-root-fs.target</filename> is reached. The service
    <filename>initrd-parse-etc.service</filename> scans
    <filename>/sysroot/etc/fstab</filename> for a possible
    <filename>/usr</filename> mount point and additional entries
    marked with the <emphasis>x-initrd.mount</emphasis> option. All
    entries found are mounted below <filename>/sysroot</filename>, and
    <filename>initrd-fs.target</filename> is reached. The service
    <filename>initrd-cleanup.service</filename> isolates to the
    <filename>initrd-switch-root.target</filename>, where cleanup
    services can run. As the very last step, the
    <filename>initrd-switch-root.service</filename> is activated,
    which will cause the system to switch its root to
    <filename>/sysroot</filename>.
    </para>

<programlisting>                                               : (beginning identical to above)
                                               :
                                               v
                                         basic.target
                                               |                                 emergency.service
                        ______________________/|                                         |
                       /                       |                                         v
                       |            initrd-root-device.target                    <emphasis>emergency.target</emphasis>
                       |                       |
                       |                       v
                       |                  sysroot.mount
                       |                       |
                       |                       v
                       |             initrd-root-fs.target
                       |                       |
                       |                       v
                       v            initrd-parse-etc.service
                (custom initrd                 |
                 services...)                  v
                       |            (sysroot-usr.mount and
                       |             various mounts marked
                       |               with fstab option
                       |              x-initrd.mount...)
                       |                       |
                       |                       v
                       |                initrd-fs.target
                       \______________________ |
                                              \|
                                               v
                                          initrd.target
                                               |
                                               v
                                     initrd-cleanup.service
                                          isolates to
                                    initrd-switch-root.target
                                               |
                                               v
                        ______________________/|
                       /                       v
                       |        initrd-udevadm-cleanup-db.service
                       v                       |
                (custom initrd                 |
                 services...)                  |
                       \______________________ |
                                              \|
                                               v
                                   initrd-switch-root.target
                                               |
                                               v
                                   initrd-switch-root.service
                                               |
                                               v
                                     Transition to Host OS</programlisting>
  </refsect1>

  <refsect1>
    <title>System Manager Shutdown</title>

    <para>System shutdown with systemd also consists of various target
    units with some minimal ordering structure applied:</para>

<programlisting>                                  (conflicts with  (conflicts with
                                    all system     all file system
                                     services)     mounts, swaps,
                                         |           cryptsetup
                                         |          devices, ...)
                                         |                |
                                         v                v
                                  shutdown.target    umount.target
                                         |                |
                                         \_______   ______/
                                                 \ /
                                                  v
                                         (various low-level
                                              services)
                                                  |
                                                  v
                                            final.target
                                                  |
            _____________________________________/ \_________________________________
           /                         |                        |                      \
           |                         |                        |                      |
           v                         v                        v                      v
systemd-reboot.service   systemd-poweroff.service   systemd-halt.service   systemd-kexec.service
           |                         |                        |                      |
           v                         v                        v                      v
    <emphasis>reboot.target</emphasis>             <emphasis>poweroff.target</emphasis>            <emphasis>halt.target</emphasis>           <emphasis>kexec.target</emphasis></programlisting>

    <para>Commonly used system shutdown targets are <emphasis>emphasized</emphasis>.</para>

    <para>Note that
    <citerefentry><refentrytitle>systemd-halt.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
    <filename>systemd-reboot.service</filename>, <filename>systemd-poweroff.service</filename> and
    <filename>systemd-kexec.service</filename> will transition the system and server manager (PID 1) into the second
    phase of system shutdown (implemented in the <filename>systemd-shutdown</filename> binary), which will unmount any
    remaining file systems, kill any remaining processes and release any other remaining resources, in a simple and
    robust fashion, without taking any service or unit concept into account anymore. At that point, regular
    applications and resources are generally terminated and released already, the second phase hence operates only as
    safety net for everything that couldn't be stopped or released for some reason during the primary, unit-based
    shutdown phase described above.</para>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry project='man-pages'><refentrytitle>boot</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-halt.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry project='die-net'><refentrytitle>dracut</refentrytitle><manvolnum>8</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>
Commit	Line	Data
013d8a39 LP	1	<?xml version='1.0'?> <!---nxml--->
013d8a39 LP	2	<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
12b42c76	3	"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
013d8a39 LP	4
013d8a39 LP	5	<!--
572eb058 ZJS	6	SPDX-License-Identifier: LGPL-2.1+
572eb058 ZJS	7
013d8a39 LP	8	This file is part of systemd.
	9
	10	Copyright 2012 Lennart Poettering
013d8a39 LP	11	-->
	12
	13	<refentry id="bootup">
	14
798d3a52 ZJS	15	<refentryinfo>
	16	<title>bootup</title>
	17	<productname>systemd</productname>
	18
	19	<authorgroup>
	20	<author>
	21	<contrib>Developer</contrib>
	22	<firstname>Lennart</firstname>
	23	<surname>Poettering</surname>
	24	<email>lennart@poettering.net</email>
	25	</author>
	26	</authorgroup>
	27	</refentryinfo>
	28
	29	<refmeta>
	30	<refentrytitle>bootup</refentrytitle>
	31	<manvolnum>7</manvolnum>
	32	</refmeta>
	33
	34	<refnamediv>
	35	<refname>bootup</refname>
	36	<refpurpose>System bootup process</refpurpose>
	37	</refnamediv>
	38
	39	<refsect1>
	40	<title>Description</title>
	41
	42	<para>A number of different components are involved in the system
	43	boot. Immediately after power-up, the system BIOS will do minimal
	44	hardware initialization, and hand control over to a boot loader
	45	stored on a persistent storage device. This boot loader will then
	46	invoke an OS kernel from disk (or the network). In the Linux case,
	47	this kernel (optionally) extracts and executes an initial RAM disk
	48	image (initrd), such as generated by
	49	<citerefentry project='die-net'><refentrytitle>dracut</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
	50	which looks for the root file system (possibly using
	51	<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
	52	for this). After the root file system is found and mounted, the
	53	initrd hands over control to the host's system manager (such as
	54	<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>)
	55	stored on the OS image, which is then responsible for probing all
	56	remaining hardware, mounting all necessary file systems and
	57	spawning all configured services.</para>
	58
	59	<para>On shutdown, the system manager stops all services, unmounts
	60	all file systems (detaching the storage technologies backing
	61	them), and then (optionally) jumps back into the initrd code which
	62	unmounts/detaches the root file system and the storage it resides
	63	on. As a last step, the system is powered down.</para>
	64
	65	<para>Additional information about the system boot process may be
	66	found in
	67	<citerefentry project='man-pages'><refentrytitle>boot</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
	68	</refsect1>
	69
	70	<refsect1>
	71	<title>System Manager Bootup</title>
	72
	73	<para>At boot, the system manager on the OS image is responsible
	74	for initializing the required file systems, services and drivers
	75	that are necessary for operation of the system. On
	76	<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
	77	systems, this process is split up in various discrete steps which
	78	are exposed as target units. (See
79	<citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>
80	for detailed information about target units.) The boot-up process
81	is highly parallelized so that the order in which specific target
82	units are reached is not deterministic, but still adheres to a
83	limited amount of ordering structure.</para>
84
85	<para>When systemd starts up the system, it will activate all
86	units that are dependencies of <filename>default.target</filename>
87	(as well as recursively all dependencies of these dependencies).
88	Usually, <filename>default.target</filename> is simply an alias of
89	<filename>graphical.target</filename> or
90	<filename>multi-user.target</filename>, depending on whether the
91	system is configured for a graphical UI or only for a text
92	console. To enforce minimal ordering between the units pulled in,
93	a number of well-known target units are available, as listed on
94	<citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
95
96	<para>The following chart is a structural overview of these
97	well-known units and their position in the boot-up logic. The
98	arrows describe which units are pulled in and ordered before which
99	other units. Units near the top are started before units nearer to
100	the bottom of the chart.</para>
013d8a39	101
24c44fdf ZJS	102	<!-- note: do not use unicode ellipsis here, because docbook will replace that
24c44fdf ZJS	103	with three dots anyway, messing up alignment -->
013d8a39	104	<programlisting>local-fs-pre.target
72b7d998 ZJS	105	\|
72b7d998 ZJS	106	v
013d8a39	107	(various mounts and (various swap (various cryptsetup
72b7d998 ZJS	108	fsck services...) devices...) devices...) (various low-level (various low-level
	109	\| \| \| services: udevd, API VFS mounts:
	110	v v v tmpfiles, random mqueue, configfs,
013d8a39	111	local-fs.target swap.target cryptsetup.target seed, sysctl, ...) debugfs, ...)
72b7d998 ZJS	112	\| \| \| \| \|
	113	\__________________\|_________________ \| ___________________\|____________________/
	114	\\|/
	115	v
	116	sysinit.target
	117	\|
	118	____________________________________/\|\________________________________________
	119	/ \| \| \| \
	120	\| \| \| \| \|
	121	v v \| v v
	122	(various (various \| (various rescue.service
	123	timers...) paths...) \| sockets...) \|
	124	\| \| \| \| v
	125	v v \| v <emphasis>rescue.target</emphasis>
	126	timers.target paths.target \| sockets.target
	127	\| \| \| \|
b44787bd	128	v \_________________ \| ___________________/
72b7d998 ZJS	129	\\|/
	130	v
	131	basic.target
	132	\|
	133	____________________________________/\| emergency.service
	134	/ \| \| \|
	135	\| \| \| v
	136	v v v <emphasis>emergency.target</emphasis>
	137	display- (various system (various system
	138	manager.service services services)
	139	\| required for \|
	140	\| graphical UIs) v
	141	\| \| <emphasis>multi-user.target</emphasis>
	142	\| \| \|
	143	\_________________ \| _________________/
	144	\\|/
	145	v
	146	<emphasis>graphical.target</emphasis></programlisting>
798d3a52 ZJS	147
	148	<para>Target units that are commonly used as boot targets are
	149	<emphasis>emphasized</emphasis>. These units are good choices as
	150	goal targets, for example by passing them to the
	151	<varname>systemd.unit=</varname> kernel command line option (see
	152	<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>)
72b7d998 ZJS	153	or by symlinking <filename>default.target</filename> to them.
72b7d998 ZJS	154	</para>
798d3a52 ZJS	155
	156	<para><filename>timers.target</filename> is pulled-in by
	157	<filename>basic.target</filename> asynchronously. This allows
	158	timers units to depend on services which become only available
	159	later in boot.</para>
	160	</refsect1>
	161
	162	<refsect1>
	163	<title>Bootup in the Initial RAM Disk (initrd)</title>
	164	<para>The initial RAM disk implementation (initrd) can be set up
	165	using systemd as well. In this case, boot up inside the initrd
	166	follows the following structure.</para>
	167
	168	<para>The default target in the initrd is
	169	<filename>initrd.target</filename>. The bootup process begins
	170	identical to the system manager bootup (see above) until it
	171	reaches <filename>basic.target</filename>. From there, systemd
	172	approaches the special target <filename>initrd.target</filename>.
6d9e45e9 JH	173
	174	Before any file systems are mounted, it must be determined whether
	175	the system will resume from hibernation or proceed with normal boot.
	176	This is accomplished by <filename>systemd-hibernate-resume@.service</filename>
	177	which must be finished before <filename>local-fs-pre.target</filename>,
	178	so no filesystems can be mounted before the check is complete.
	179
7163e1ca DD	180	When the root device becomes available,
7163e1ca DD	181	<filename>initd-root-device.target</filename> is reached.
798d3a52 ZJS	182	If the root device can be mounted at
	183	<filename>/sysroot</filename>, the
	184	<filename>sysroot.mount</filename> unit becomes active and
	185	<filename>initrd-root-fs.target</filename> is reached. The service
	186	<filename>initrd-parse-etc.service</filename> scans
	187	<filename>/sysroot/etc/fstab</filename> for a possible
	188	<filename>/usr</filename> mount point and additional entries
	189	marked with the <emphasis>x-initrd.mount</emphasis> option. All
	190	entries found are mounted below <filename>/sysroot</filename>, and
	191	<filename>initrd-fs.target</filename> is reached. The service
	192	<filename>initrd-cleanup.service</filename> isolates to the
	193	<filename>initrd-switch-root.target</filename>, where cleanup
	194	services can run. As the very last step, the
	195	<filename>initrd-switch-root.service</filename> is activated,
	196	which will cause the system to switch its root to
	197	<filename>/sysroot</filename>.
	198	</para>
	199
72b7d998 ZJS	200	<programlisting> : (beginning identical to above)
	201	:
	202	v
	203	basic.target
	204	\| emergency.service
	205	______________________/\| \|
	206	/ \| v
7163e1ca DD	207	\| initrd-root-device.target <emphasis>emergency.target</emphasis>
	208	\| \|
	209	\| v
	210	\| sysroot.mount
72b7d998 ZJS	211	\| \|
	212	\| v
	213	\| initrd-root-fs.target
	214	\| \|
	215	\| v
	216	v initrd-parse-etc.service
	217	(custom initrd \|
	218	services...) v
	219	\| (sysroot-usr.mount and
	220	\| various mounts marked
	221	\| with fstab option
	222	\| x-initrd.mount...)
	223	\| \|
	224	\| v
	225	\| initrd-fs.target
	226	\______________________ \|
	227	\\|
	228	v
	229	initrd.target
	230	\|
	231	v
	232	initrd-cleanup.service
	233	isolates to
	234	initrd-switch-root.target
	235	\|
	236	v
	237	______________________/\|
	238	/ v
	239	\| initrd-udevadm-cleanup-db.service
	240	v \|
	241	(custom initrd \|
	242	services...) \|
	243	\______________________ \|
	244	\\|
	245	v
	246	initrd-switch-root.target
	247	\|
	248	v
	249	initrd-switch-root.service
	250	\|
	251	v
	252	Transition to Host OS</programlisting>
798d3a52 ZJS	253	</refsect1>
798d3a52 ZJS	254
798d3a52 ZJS	255	<refsect1>
	256	<title>System Manager Shutdown</title>
	257
	258	<para>System shutdown with systemd also consists of various target
	259	units with some minimal ordering structure applied:</para>
	260
72b7d998 ZJS	261	<programlisting> (conflicts with (conflicts with
	262	all system all file system
	263	services) mounts, swaps,
	264	\| cryptsetup
	265	\| devices, ...)
	266	\| \|
	267	v v
	268	shutdown.target umount.target
	269	\| \|
	270	\_______ ______/
	271	\ /
	272	v
	273	(various low-level
	274	services)
	275	\|
	276	v
	277	final.target
	278	\|
	279	_____________________________________/ \_________________________________
	280	/ \| \| \
	281	\| \| \| \|
	282	v v v v
0e0320e0	283	systemd-reboot.service systemd-poweroff.service systemd-halt.service systemd-kexec.service
72b7d998 ZJS	284	\| \| \| \|
	285	v v v v
	286	<emphasis>reboot.target</emphasis> <emphasis>poweroff.target</emphasis> <emphasis>halt.target</emphasis> <emphasis>kexec.target</emphasis></programlisting>
798d3a52	287
e799056e LP	288	<para>Commonly used system shutdown targets are <emphasis>emphasized</emphasis>.</para>
	289
	290	<para>Note that
39e4f5bc	291	<citerefentry><refentrytitle>systemd-halt.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
e799056e LP	292	<filename>systemd-reboot.service</filename>, <filename>systemd-poweroff.service</filename> and
	293	<filename>systemd-kexec.service</filename> will transition the system and server manager (PID 1) into the second
	294	phase of system shutdown (implemented in the <filename>systemd-shutdown</filename> binary), which will unmount any
	295	remaining file systems, kill any remaining processes and release any other remaining resources, in a simple and
	296	robust fashion, without taking any service or unit concept into account anymore. At that point, regular
	297	applications and resources are generally terminated and released already, the second phase hence operates only as
	298	safety net for everything that couldn't be stopped or released for some reason during the primary, unit-based
	299	shutdown phase described above.</para>
798d3a52 ZJS	300	</refsect1>
	301
	302	<refsect1>
	303	<title>See Also</title>
	304	<para>
	305	<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
	306	<citerefentry project='man-pages'><refentrytitle>boot</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
	307	<citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
	308	<citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
e799056e	309	<citerefentry><refentrytitle>systemd-halt.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
798d3a52 ZJS	310	<citerefentry project='die-net'><refentrytitle>dracut</refentrytitle><manvolnum>8</manvolnum></citerefentry>
	311	</para>
	312	</refsect1>
013d8a39 LP	313
013d8a39 LP	314	</refentry>