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<?xml version="1.0"?>
<!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="systemd-volatile-root.service">
<refentryinfo>
<title>systemd-volatile-root.service</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>systemd-volatile-root.service</refentrytitle>
<manvolnum>8</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd-volatile-root.service</refname>
<refname>systemd-volatile-root</refname>
<refpurpose>Make the root file system volatile</refpurpose>
</refnamediv>
<refsynopsisdiv>
<para><filename>systemd-volatile-root.service</filename></para>
<para><filename>/usr/lib/systemd/systemd-volatile-root</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><filename>systemd-volatile-root.service</filename> is a service that replaces the root directory with a
volatile memory file system (<literal>tmpfs</literal>), mounting the original (non-volatile)
<filename>/usr/</filename> inside it read-only. This way, vendor data from <filename>/usr/</filename> is available as
usual, but all configuration data in <filename>/etc/</filename>, all state data in <filename>/var/</filename> and all
other resources stored directly under the root directory are reset on boot and lost at shutdown, enabling fully
stateless systems.</para>
<para>This service is only enabled if full volatile mode is selected, for example by specifying
<literal>systemd.volatile=yes</literal> on the kernel command line. This service runs only in the initrd,
before the system transitions to the host's root directory. Note that this service is not used if
<literal>systemd.volatile=state</literal> is used, as in that mode the root directory is non-volatile.
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
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