dbus >= 1.4.0 (strictly speaking optional, but recommended)
NOTE: If using dbus < 1.9.18, you should override the default
policy directory (--with-dbuspolicydir=/etc/dbus-1/system.d).
- dracut (optional)
polkit (optional)
To build in directory build/:
few bits of runtime information from the initrd to systemd in order to avoid
duplicate work and to provide performance data to the administrator. In this
page we attempt to roughly describe the interfaces that exist between the
-initrd and systemd. These interfaces are currently used by dracut and the
-ArchLinux initrds.
+initrd and systemd. These interfaces are currently used by
+[mkosi](https://github.com/systemd/mkosi)-generated initrds, dracut and the
+Arch Linux initrds.
* The initrd should mount `/run/` as a tmpfs and pass it pre-mounted when
jumping into the main system when executing systemd. The mount options should
in this sense as a term that is unrelated to the actual backing technologies
used.
-Oh, and one last question before closing: instead of implementing these
-features in your own distro's initrd, may I suggest just using Dracut instead?
-It's all already implemented there!
-
## Using systemd inside an initrd
It is also possible and recommended to implement the initrd itself based on
| [hostnamed](https://www.freedesktop.org/software/systemd/man/org.freedesktop.hostname1.html) | D-Bus | yes | yes | GNOME | yes | [Ubuntu](https://launchpad.net/ubuntu/+source/ubuntu-system-service), [Gentoo](http://www.gentoo.org/proj/en/desktop/gnome/openrc-settingsd.xml), [BSD](http://uglyman.kremlin.cc/gitweb/gitweb.cgi?p=systembsd.git;a=summary) | partially |
| [localed](https://www.freedesktop.org/software/systemd/man/org.freedesktop.locale1.html) | D-Bus | yes | yes | GNOME | yes | [Ubuntu](https://launchpad.net/ubuntu/+source/ubuntu-system-service), [Gentoo](http://www.gentoo.org/proj/en/desktop/gnome/openrc-settingsd.xml), [BSD](http://uglyman.kremlin.cc/gitweb/gitweb.cgi?p=systembsd.git;a=summary) | partially |
| [timedated](https://www.freedesktop.org/software/systemd/man/org.freedesktop.timedate1.html) | D-Bus | yes | yes | GNOME | yes | [Gentoo](http://www.gentoo.org/proj/en/desktop/gnome/openrc-settingsd.xml), [BSD](http://uglyman.kremlin.cc/gitweb/gitweb.cgi?p=systembsd.git;a=summary) | partially |
-| [initrd interface](INITRD_INTERFACE.md) | Environment, flag files | yes | yes | dracut, ArchLinux | yes | ArchLinux | no |
+| [initrd interface](INITRD_INTERFACE.md) | Environment, flag files | yes | yes | mkosi, dracut, ArchLinux | yes | ArchLinux | no |
| [Container interface](CONTAINER_INTERFACE.md) | Environment, Mounts | yes | yes | libvirt/LXC | yes | - | no |
| [Boot Loader interface](BOOT_LOADER_INTERFACE.md) | EFI variables | yes | yes | gummiboot | yes | - | no |
| [Service bus API](https://www.freedesktop.org/software/systemd/man/org.freedesktop.systemd1.html) | D-Bus | yes | yes | system-config-services | no | - | no |
boot loader will then invoke an OS kernel from disk (or the network). On systems using EFI or other types
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='man-pages'><refentrytitle>dracut</refentrytitle><manvolnum>8</manvolnum></citerefentry>, which
- looks for the root file system. Nowadays this is implemented as an "initramfs" — a compressed CPIO
- archive that the kernel extracts into a tmpfs. In the past normal file systems using an in-memory block
- device (ramdisk) were used, and the name "initrd" is still used to describe both concepts. It's the boot
- loader or the firmware that loads both the kernel and initrd/initramfs images into memory, but the kernel
- which interprets it as a file system.
+ <para>The kernel (optionally) mounts an in-memory file system, which looks for the root file system.
+ Nowadays this is implemented as an "initramfs" — a compressed CPIO archive that the kernel extracts into
+ a tmpfs. In the past normal file systems using an in-memory block device (ramdisk) were used, and the
+ name "initrd" is still used to describe both concepts. It's the boot loader or the firmware that loads
+ both the kernel and initrd/initramfs images into memory, but the kernel which interprets it as a file
+ system.
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> may be used
to manage services in the initrd, similarly to the real system.</para>
<member><citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>systemd-halt.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
- <member><citerefentry project='man-pages'><refentrytitle>dracut</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
</simplelist></para>
</refsect1>
and
<citerefentry project='man-pages'><refentrytitle>bootparam</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
- <para>For command line parameters understood by the initrd, see
- <citerefentry project='man-pages'><refentrytitle>dracut.cmdline</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
- or the documentation of the specific initrd implementation of your
- installation.</para>
+ <para>For command line parameters understood by the initrd, see the documentation of the specific initrd
+ implementation of your installation.</para>
</refsect1>
<refsect1>
<member><citerefentry project='man-pages'><refentrytitle>bootparam</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>systemd.system-credentials</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>smbios-type-11</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
- <member><citerefentry project='man-pages'><refentrytitle>dracut.cmdline</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>systemd-debug-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>systemd-fsck@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>systemd-quotacheck.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
<para>Note that the changes performed using this tool might require the initrd to be rebuilt to take
effect during early system boot. The initrd is not rebuilt automatically by
- <filename>localectl</filename>, this task has to be performed manually, usually using a tool like
- <citerefentry
- project='man-pages'><refentrytitle>dracut</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
- </para>
+ <filename>localectl</filename>, this task has to be performed manually, usually by reinstalling the
+ distribution's kernel package.</para>
<para>Note that
<citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
<member><citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>systemd-localed.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
- <member><citerefentry project='man-pages'><refentrytitle>dracut</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
</simplelist></para>
</refsect1>
compatibility with applications only looking at
<filename>/etc/</filename>. A relative symlink instead of an
absolute symlink is necessary to avoid breaking the link in a
- chroot or initrd environment such as dracut.</para>
+ chroot or initrd environment.</para>
<para><filename>os-release</filename> contains data that is
defined by the operating system vendor and should generally not be
projects / thirdparty / systemd.git / commitdiff
