of firmware, this firmware may also load the kernel directly.</para>
<para>The kernel (optionally) mounts an in-memory file system, often generated by
- <citerefentry project='die-net'><refentrytitle>dracut</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>dracut</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
which looks for the root file system. Nowadays this is usually implemented as an initramfs — a compressed
archive which is extracted when the kernel boots up into a lightweight in-memory file system based on
tmpfs, but in the past normal file systems using an in-memory block device (ramdisk) were used, and the
<!-- note: do not use unicode ellipsis here, because docbook will replace that
with three dots anyway, messing up alignment -->
-<programlisting>(various cryptsetup
- devices...)
- |
- v
- cryptsetup.target
- |
- v
- local-fs-pre.target
- |
- v
-(various mounts and (various swap
- fsck services...) devices...) (various low-level (various low-level
- | | services: udevd, API VFS mounts:
- v v tmpfiles, random mqueue, configfs,
- local-fs.target swap.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>
+<programlisting> cryptsetup-pre.target
+ |
+(various low-level v
+ API VFS mounts: (various cryptsetup devices...)
+ mqueue, configfs, | |
+ debugfs, ...) v |
+ | cryptsetup.target |
+ | (various swap | | remote-fs-pre.target
+ | devices...) | | | |
+ | | | | | v
+ | v local-fs-pre.target | | | (network file systems)
+ | swap.target | | v v |
+ | | v | remote-cryptsetup.target |
+ | | (various low-level (various mounts and | | |
+ | | services: udevd, fsck services...) | | remote-fs.target
+ | | tmpfiles, random | | | /
+ | | seed, sysctl, ...) v | | /
+ | | | local-fs.target | | /
+ | | | | | | /
+ \____|______|_______________ ______|___________/ | /
+ \ / | /
+ v | /
+ sysinit.target | /
+ | | /
+ ______________________/|\_____________________ | /
+ / | | | \ | /
+ | | | | | | /
+ v v | v | | /
+ (various (various | (various | |/
+ timers...) paths...) | sockets...) | |
+ | | | | | |
+ v v | v | |
+timers.target paths.target | sockets.target | |
+ | | | | v |
+ v \_______ | _____/ rescue.service |
+ \|/ | |
+ v v |
+ basic.target <emphasis>rescue.target</emphasis> |
+ | |
+ ________v____________________ |
+ / | \ |
+ | | | |
+ v v v |
+ display- (various system (various system |
+ manager.service services services) |
+ | required for | |
+ | graphical UIs) v v
+ | | <emphasis>multi-user.target</emphasis>
+emergency.service | | |
+ | \_____________ | _____________/
+ v \|/
+<emphasis>emergency.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
later in boot.</para>
</refsect1>
+ <refsect1>
+ <title>User manager startup</title>
+
+ <para>The system manager starts the <filename>user@<replaceable>uid</replaceable>.service</filename> unit
+ for each user, which launches a separate unprivileged instance of <command>systemd</command> for each
+ user — the user manager. Similarly to the system manager, the user manager starts units which are pulled
+ in by <filename>default.target</filename>. The following chart is a structural overview of the well-known
+ user units. For non-graphical sessions, <filename>default.target</filename> is used. Whenever the user
+ logs into a graphical session, the login manager will start the
+ <filename>graphical-session.target</filename> target that is used to pull in units required for the
+ graphical session. A number of targets (shown on the right side) are started when specific hardware is
+ available to the user.</para>
+
+<programlisting>
+ (various (various (various
+ timers...) paths...) sockets...) (sound devices)
+ | | | |
+ v v v v
+ timers.target paths.target sockets.target sound.target
+ | | |
+ \______________ _|_________________/ (bluetooth devices)
+ \ / |
+ V v
+ basic.target bluetooth.target
+ |
+ __________/ \_______ (smartcard devices)
+ / \ |
+ | | v
+ | v smartcard.target
+ v graphical-session-pre.target
+ (various user services) | (printers)
+ | v |
+ | (services for the graphical session) v
+ | | printer.target
+ v v
+ <emphasis>default.target</emphasis> graphical-session.target</programlisting>
+
+ </refsect1>
+
<refsect1>
<title>Bootup in the Initial RAM Disk (initrd)</title>
<para>The initial RAM disk implementation (initrd) can be set up
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.
+ <filename>initrd-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
<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>
+ <citerefentry project='man-pages'><refentrytitle>dracut</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</para>
</refsect1>
projects / thirdparty / systemd.git / blobdiff