]>
Commit | Line | Data |
---|---|---|
2a5a41e8 DR |
1 | <?xml version="1.0"?> |
2 | <!--*-nxml-*--> | |
12b42c76 | 3 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
2a5a41e8 DR |
4 | <!-- |
5 | This file is part of systemd. | |
6 | ||
7 | Copyright 2014 Didier Roche | |
8 | ||
9 | systemd is free software; you can redistribute it and/or modify it | |
10 | under the terms of the GNU Lesser General Public License as published by | |
11 | the Free Software Foundation; either version 2.1 of the License, or | |
12 | (at your option) any later version. | |
13 | ||
14 | systemd is distributed in the hope that it will be useful, but | |
15 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | Lesser General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU Lesser General Public License | |
20 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
21 | --> | |
22 | <refentry id="systemd-machine-id-commit.service"> | |
23 | ||
798d3a52 ZJS |
24 | <refentryinfo> |
25 | <title>systemd-machine-id-commit.service</title> | |
26 | <productname>systemd</productname> | |
27 | ||
28 | <authorgroup> | |
29 | <author> | |
30 | <contrib>Developer</contrib> | |
31 | <firstname>Didier</firstname> | |
32 | <surname>Roche</surname> | |
33 | <email>didrocks@ubuntu.com</email> | |
34 | </author> | |
35 | </authorgroup> | |
36 | </refentryinfo> | |
37 | ||
38 | <refmeta> | |
39 | <refentrytitle>systemd-machine-id-commit.service</refentrytitle> | |
40 | <manvolnum>8</manvolnum> | |
41 | </refmeta> | |
42 | ||
43 | <refnamediv> | |
44 | <refname>systemd-machine-id-commit.service</refname> | |
a8eaaee7 | 45 | <refpurpose>Commit a transient machine ID to disk</refpurpose> |
798d3a52 ZJS |
46 | </refnamediv> |
47 | ||
48 | <refsynopsisdiv> | |
49 | <para><filename>systemd-machine-id-commit.service</filename></para> | |
798d3a52 ZJS |
50 | </refsynopsisdiv> |
51 | ||
52 | <refsect1> | |
53 | <title>Description</title> | |
54 | ||
4a9b1dd4 | 55 | <para><filename>systemd-machine-id-commit.service</filename> is an |
b938cb90 | 56 | early boot service responsible for committing transient |
4a9b1dd4 | 57 | <filename>/etc/machine-id</filename> files to a writable disk file |
798d3a52 ZJS |
58 | system. See |
59 | <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
4a9b1dd4 LP |
60 | for more information about machine IDs.</para> |
61 | ||
62 | <para>This service is started after | |
63 | <filename>local-fs.target</filename> in case | |
64 | <filename>/etc/machine-id</filename> is a mount point of its own | |
65 | (usually from a memory file system such as | |
66 | <literal>tmpfs</literal>) and /etc is writable. The service will | |
67 | invoke <command>systemd-machine-id-setup --commit</command>, which | |
68 | writes the current transient machine ID to disk and unmount the | |
798d3a52 | 69 | <filename>/etc/machine-id</filename> file in a race-free manner to |
4a9b1dd4 LP |
70 | ensure that file is always valid and accessible for other |
71 | processes. See | |
72 | <citerefentry><refentrytitle>systemd-machine-id-setup</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
73 | for details.</para> | |
74 | ||
75 | <para>The main use case of this service are systems where | |
76 | <filename>/etc/machine-id</filename> is read-only and initially | |
b938cb90 | 77 | not initialized. In this case, the system manager will generate a |
4a9b1dd4 LP |
78 | transient machine ID file on a memory file system, and mount it |
79 | over <filename>/etc/machine-id</filename>, during the early boot | |
80 | phase. This service is then invoked in a later boot phase, as soon | |
81 | as <filename>/etc</filename> has been remounted writable and the | |
82 | ID may thus be committed to disk to make it permanent.</para> | |
798d3a52 ZJS |
83 | </refsect1> |
84 | ||
85 | <refsect1> | |
86 | <title>See Also</title> | |
87 | <para> | |
88 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
798d3a52 ZJS |
89 | <citerefentry><refentrytitle>systemd-machine-id-setup</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
90 | <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
91 | <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
92 | </para> | |
93 | </refsect1> | |
2a5a41e8 DR |
94 | |
95 | </refentry> |