<para>As a safety check
<command>systemd-nspawn</command> will verify the
- existence of <filename>/etc/os-release</filename> in
- the container tree before starting the container (see
+ existence of <filename>/usr/lib/os-release</filename>
+ or <filename>/etc/os-release</filename> in the
+ container tree before starting the container (see
<citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry>). It
might be necessary to add this file to the container
tree manually if the OS of the container is too old to
mounts.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><option>--tmpfs=</option></term>
+
+ <listitem><para>Mount a tmpfs file
+ system into the container. Takes a
+ single absolute path argument that
+ specifies where to mount the tmpfs
+ instance to (in which case the
+ directory access mode will be chosen
+ as 0755, owned by root/root), or
+ optionally a colon-separated pair of
+ path and mount option string, that is
+ used for mounting (in which case the
+ kernel default for access mode and
+ owner will be chosen, unless otherwise
+ specified). This option is
+ particularly useful for mounting
+ directories such as
+ <filename>/var</filename> as tmpfs, to
+ allow state-less systems, in
+ particular when combined with
+ <option>--read-only</option>.</para></listitem>
+ </varlistentry>
+
<varlistentry>
<term><option>--setenv=</option></term>