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systemd/man/systemd-machine-id-setup.xml
Zbigniew Jędrzejewski-Szmek 11a1589223 tree-wide: drop license boilerplate
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.

I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
2018-04-06 18:58:55 +02:00

174 lines
6.4 KiB
XML

<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
<!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="systemd-machine-id-setup"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>systemd-machine-id-setup</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
<author>
<contrib>Developer</contrib>
<firstname>Didier</firstname>
<surname>Roche</surname>
<email>didrocks@ubuntu.com</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>systemd-machine-id-setup</refentrytitle>
<manvolnum>1</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd-machine-id-setup</refname>
<refpurpose>Initialize the machine ID in /etc/machine-id</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>systemd-machine-id-setup</command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><command>systemd-machine-id-setup</command> may be used by
system installer tools to initialize the machine ID stored in
<filename>/etc/machine-id</filename> at install time, with a
provisioned or randomly generated ID. See
<citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for more information about this file.</para>
<para>If the tool is invoked without the <option>--commit</option>
switch, <filename>/etc/machine-id</filename> is initialized with a
valid, new machined ID if it is missing or empty. The new machine
ID will be acquired in the following fashion:</para>
<orderedlist>
<listitem><para>If a valid D-Bus machine ID is already
configured for the system, the D-Bus machine ID is copied and
used to initialize the machine ID in
<filename>/etc/machine-id</filename>.</para></listitem>
<listitem><para>If run inside a KVM virtual machine and a UUID
is configured (via the <option>-uuid</option>
option), this UUID is used to initialize the machine ID. The
caller must ensure that the UUID passed is sufficiently unique
and is different for every booted instance of the
VM.</para></listitem>
<listitem><para>Similarly, if run inside a Linux container
environment and a UUID is configured for the container, this is
used to initialize the machine ID. For details, see the
documentation of the <ulink
url="https://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container
Interface</ulink>.</para></listitem>
<listitem><para>Otherwise, a new ID is randomly
generated.</para></listitem>
</orderedlist>
<para>The <option>--commit</option> switch may be used to commit a
transient machined ID to disk, making it persistent. For details,
see below.</para>
<para>Use
<citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
to initialize the machine ID on mounted (but not booted) system
images.</para>
</refsect1>
<refsect1>
<title>Options</title>
<para>The following options are understood:</para>
<variablelist>
<varlistentry>
<term><option>--root=<replaceable>root</replaceable></option></term>
<listitem><para>Takes a directory path as argument. All paths
operated will be prefixed with the given alternate
<replaceable>root</replaceable> path, including the path for
<filename>/etc/machine-id</filename> itself.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--commit</option></term>
<listitem><para>Commit a transient machine ID to disk. This
command may be used to convert a transient machine ID into a
persistent one. A transient machine ID file is one that was
bind mounted from a memory file system (usually
<literal>tmpfs</literal>) to
<filename>/etc/machine-id</filename> during the early phase of
the boot process. This may happen because
<filename>/etc</filename> is initially read-only and was
missing a valid machine ID file at that point.</para>
<para>This command will execute no operation if
<filename>/etc/machine-id</filename> is not mounted from a
memory file system, or if <filename>/etc</filename> is
read-only. The command will write the current transient
machine ID to disk and unmount the
<filename>/etc/machine-id</filename> mount point in a
race-free manner to ensure that this file is always valid and
accessible for other processes.</para>
<para>This command is primarily used by the
<citerefentry><refentrytitle>systemd-machine-id-commit.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
early boot service.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--print</option></term>
<listitem><para>Print the machine ID generated or committed after the operation is complete.</para></listitem>
</varlistentry>
<xi:include href="standard-options.xml" xpointer="help" />
<xi:include href="standard-options.xml" xpointer="version" />
</variablelist>
</refsect1>
<refsect1>
<title>Exit status</title>
<para>On success, 0 is returned, a non-zero failure code
otherwise.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-machine-id-commit.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry project='dbus'><refentrytitle>dbus-uuidgen</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>