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diff --git a/man/bootup.xml b/man/bootup.xml deleted file mode 100644 index 4cc4bafab7..0000000000 --- a/man/bootup.xml +++ /dev/null @@ -1,226 +0,0 @@ -<?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"> - -<!-- - This file is part of systemd. - - Copyright 2012 Lennart Poettering - - systemd is free software; you can redistribute it and/or modify it - under the terms of the GNU Lesser General Public License as published by - the Free Software Foundation; either version 2.1 of the License, or - (at your option) any later version. - - systemd is distributed in the hope that it will be useful, but - WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public License - along with systemd; If not, see <http://www.gnu.org/licenses/>. ---> - -<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 now (optionally) extracts and - executes an initial RAM disk image (initrd) such as - <citerefentry><refentrytitle>dracut</refentrytitle><manvolnum>8</manvolnum></citerefentry> - which looks for the root file system. After the root - file system is found and mounted the initrd hands over - control to the 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 last step the system is powered down.</para> - - <para>Additional information about the system boot - process may be found in - <citerefentry><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> - -<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 - (various | rescue.service - sockets...) | | - | | v - v | <emphasis>rescue.target</emphasis> - sockets.target | - | | - \_________________ | - \| - 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> - </refsect1> - - <refsect1> - <title>System Manager Shutdown</title> - - <para>System shutdown 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> - </refsect1> - - <refsect1> - <title>See Also</title> - <para> - <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, - <citerefentry><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> - </para> - </refsect1> - -</refentry> |