blob: 177fe892a650c89a239118393eb8cebedfd11a59 [file] [log] [blame]
<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="systemd-machine-id-setup"
<refpurpose>Initialize the machine ID in /etc/machine-id</refpurpose>
<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
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>
<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
<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
<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="">Container Interface</ulink>.</para></listitem>
<listitem><para>Otherwise, a new ID is randomly
<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>
to initialize the machine ID on mounted (but not booted) system
<para>The following options are understood:</para>
<listitem><para>Takes a directory path as argument. All paths operated on will be prefixed with the
given alternate <replaceable>root</replaceable> path, including the path for
<filename>/etc/machine-id</filename> itself.</para></listitem>
<listitem><para>Takes a path to a device node or regular file as argument. This is similar to
<option>--root=</option> as described above, but operates on a disk image instead of a directory
<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
early boot service.</para></listitem>
<listitem><para>Print the machine ID generated or committed after the operation is complete.</para></listitem>
<xi:include href="standard-options.xml" xpointer="help" />
<xi:include href="standard-options.xml" xpointer="version" />
<title>Exit status</title>
<para>On success, 0 is returned, a non-zero failure code
<title>See Also</title>
<citerefentry project='dbus'><refentrytitle>dbus-uuidgen</refentrytitle><manvolnum>1</manvolnum></citerefentry>,