3 <!DOCTYPE refentry PUBLIC
"-//OASIS//DTD DocBook XML V4.5//EN"
4 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
5 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
6 <refentry id=
"systemd-volatile-root.service">
9 <title>systemd-volatile-root.service
</title>
10 <productname>systemd
</productname>
14 <refentrytitle>systemd-volatile-root.service
</refentrytitle>
15 <manvolnum>8</manvolnum>
19 <refname>systemd-volatile-root.service
</refname>
20 <refname>systemd-volatile-root
</refname>
21 <refpurpose>Make the root file system volatile
</refpurpose>
25 <para><filename>systemd-volatile-root.service
</filename></para>
26 <para><filename>/usr/lib/systemd/systemd-volatile-root
</filename></para>
30 <title>Description
</title>
32 <para><filename>systemd-volatile-root.service
</filename> is a service that replaces the root directory with a
33 volatile memory file system (
<literal>tmpfs
</literal>), mounting the original (non-volatile)
34 <filename>/usr
</filename> inside it read-only. This way, vendor data from
<filename>/usr
</filename> is available as
35 usual, but all configuration data in
<filename>/etc
</filename>, all state data in
<filename>/var
</filename> and all
36 other resources stored directly under the root directory are reset on boot and lost at shutdown, enabling fully
37 stateless systems.
</para>
39 <para>This service is only enabled if full volatile mode is selected, for example by specifying
40 <literal>systemd.volatile=yes
</literal> on the kernel command line. This service runs only in the initial RAM disk
41 (
"initrd"), before the system transitions to the host's root directory. Note that this service is not used if
42 <literal>systemd.volatile=state
</literal> is used, as in that mode the root directory is non-volatile.
</para>
46 <title>See Also
</title>
48 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
49 <citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
50 <citerefentry><refentrytitle>kernel-command-line
</refentrytitle><manvolnum>7</manvolnum></citerefentry>