summaryrefslogtreecommitdiff
path: root/man/systemd-machine-id-setup.xml
blob: bfcd74f4365111bf2efb68e0c3652c809e83b463 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
<?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">

<!--
  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="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 was 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="http://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>

      <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>