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1 | <?xml version="1.0"?> |
2 | <!--*-nxml-*--> | |
3 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> | |
4 | <!-- | |
572eb058 ZJS |
5 | SPDX-License-Identifier: LGPL-2.1+ |
6 | ||
91214a37 LP |
7 | This file is part of systemd. |
8 | ||
9 | Copyright 2016 Lennart Poettering | |
10 | ||
11 | systemd is free software; you can redistribute it and/or modify it | |
12 | under the terms of the GNU Lesser General Public License as published by | |
13 | the Free Software Foundation; either version 2.1 of the License, or | |
14 | (at your option) any later version. | |
15 | ||
16 | systemd is distributed in the hope that it will be useful, but | |
17 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
19 | Lesser General Public License for more details. | |
20 | ||
21 | You should have received a copy of the GNU Lesser General Public License | |
22 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
23 | --> | |
24 | <refentry id="systemd-volatile-root.service"> | |
25 | ||
26 | <refentryinfo> | |
27 | <title>systemd-volatile-root.service</title> | |
28 | <productname>systemd</productname> | |
29 | ||
30 | <authorgroup> | |
31 | <author> | |
32 | <contrib>Developer</contrib> | |
33 | <firstname>Lennart</firstname> | |
34 | <surname>Poettering</surname> | |
35 | <email>lennart@poettering.net</email> | |
36 | </author> | |
37 | </authorgroup> | |
38 | </refentryinfo> | |
39 | ||
40 | <refmeta> | |
41 | <refentrytitle>systemd-volatile-root.service</refentrytitle> | |
42 | <manvolnum>8</manvolnum> | |
43 | </refmeta> | |
44 | ||
45 | <refnamediv> | |
46 | <refname>systemd-volatile-root.service</refname> | |
47 | <refname>systemd-volatile-root</refname> | |
48 | <refpurpose>Make the root file system volatile</refpurpose> | |
49 | </refnamediv> | |
50 | ||
51 | <refsynopsisdiv> | |
52 | <para><filename>systemd-volatile-root.service</filename></para> | |
53 | <para><filename>/usr/lib/systemd/systemd-volatile-root</filename></para> | |
54 | </refsynopsisdiv> | |
55 | ||
56 | <refsect1> | |
57 | <title>Description</title> | |
58 | ||
59 | <para><filename>systemd-volatile-root.service</filename> is a service that replaces the root directory with a | |
60 | volatile memory file system (<literal>tmpfs</literal>), mounting the original (non-volatile) | |
61 | <filename>/usr</filename> inside it read-only. This way, vendor data from <filename>/usr</filename> is available as | |
62 | usual, but all configuration data in <filename>/etc</filename>, all state data in <filename>/var</filename> and all | |
63 | other resources stored directly under the root directory are reset on boot and lost at shutdown, enabling fully | |
64 | stateless systems.</para> | |
65 | ||
66 | <para>This service is only enabled if full volatile mode is selected, for example by specifying | |
67 | <literal>systemd.volatile=yes</literal> on the kernel command line. This service runs only in the initial RAM disk | |
68 | ("initrd"), before the system transitions to the host's root directory. Note that this service is not used if | |
69 | <literal>systemd.volatile=state</literal> is used, as in that mode the root directory is non-volatile.</para> | |
70 | </refsect1> | |
71 | ||
72 | <refsect1> | |
73 | <title>See Also</title> | |
74 | <para> | |
75 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
76 | <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
77 | <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
78 | </para> | |
79 | </refsect1> | |
80 | ||
81 | </refentry> |