<term><option>--directory=</option></term>
<listitem><para>Directory to use as
- file system root for the container. If
- neither <option>--directory=</option>
- nor <option>--image=</option> are
+ file system root for the container.</para>
+
+ <para>If neither
+ <option>--directory=</option>, nor
+ <option>--image=</option> is specified
+ the directory is determined as
+ <filename>/var/lib/container/</filename>
+ suffixed by the machine name as
+ specified with
+ <option>--machine=</option>. If
+ neither <option>--directory=</option>,
+ <option>--image=</option>, nor
+ <option>--machine=</option> are
specified, the current directory will
- be used. May not be specified together with
+ be used. May not be specified together
+ with
<option>--image=</option>.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><option>--template=</option></term>
+
+ <listitem><para>Directory or
+ <literal>btrfs</literal> subvolume to
+ use as template for the container's
+ root directory. If this is specified
+ and the container's root directory (as
+ configured by
+ <option>--directory=</option>) does
+ not yet exist it is created as
+ <literal>btrfs</literal> subvolume and
+ populated from this template
+ tree. Ideally, the specified template
+ path refers to the root of a
+ <literal>btrfs</literal> subvolume, in
+ which case a simple copy-on-write
+ snapshot is taken, and populating the
+ root directory is instant. If the
+ specified template path does not refer
+ to the root of a
+ <literal>btrfs</literal> subvolume (or
+ not even to a <literal>btrfs</literal>
+ file system at all), the tree is
+ copied, which can be substantially
+ more time-consuming. Note that if this
+ option is used the container's root
+ directory (in contrast to the template
+ directory!) must be located on a
+ <literal>btrfs</literal> file system,
+ so that the <literal>btrfs</literal>
+ subvolume may be created. May not be
+ specified together with
+ <option>--image=</option> or
+ <option>--ephemeral</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>-x</option></term>
+ <term><option>--ephemeral</option></term>
+
+ <listitem><para>If specified, the
+ container is run with a temporary
+ <literal>btrfs</literal> snapshot of
+ its root directory (as configured with
+ <option>--directory=</option>), that
+ is removed immediately when the
+ container terminates. This option is
+ only supported if the root file system
+ is <literal>btrfs</literal>. May not
+ be specified together with
+ <option>--image=</option> or
+ <option>--template=</option>.</para></listitem>
+ </varlistentry>
+
<varlistentry>
<term><option>-i</option></term>
<term><option>--image=</option></term>
partitions, swap partitions or EFI
system partitions are not mounted. May
not be specified together with
- <option>--directory=</option>.</para></listitem>
+ <option>--directory=</option>,
+ <option>--template=</option> or
+ <option>--ephemeral</option>.</para></listitem>
</varlistentry>
<varlistentry>
<listitem><para>Sets the machine name
for this container. This name may be
- used to identify this container on the
- host, and is used to initialize the
- container's hostname (which the
- container can choose to override,
- however). If not specified, the last
- component of the root directory of the
- container is used.</para></listitem>
+ used to identify this container during
+ its runtime (for example in tools like
+ <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ and similar), and is used to
+ initialize the container's hostname
+ (which the container can choose to
+ override, however). If not specified,
+ the last component of the root
+ directory path of the container is
+ used, possibly suffixed with a random
+ identifier in case
+ <option>--ephemeral</option> mode is
+ selected. If the root directory
+ selected is the host's root directory
+ the host's hostname is used as default
+ instead.</para></listitem>
</varlistentry>
<varlistentry>
versa). Takes one of
<literal>no</literal>,
<literal>host</literal>,
+ <literal>try-host</literal>,
<literal>guest</literal>,
+ <literal>try-guest</literal>,
<literal>auto</literal>. If
<literal>no</literal>, the journal is
not linked. If <literal>host</literal>,
guest file system (beneath
<filename>/var/log/journal/<replaceable>machine-id</replaceable></filename>)
and the subdirectory is symlinked into the host
- at the same location. If
- <literal>auto</literal> (the default),
+ at the same location. <literal>try-host</literal>
+ and <literal>try-guest</literal> do the same
+ but do not fail if the host does not have
+ persistent journalling enabled.
+ If <literal>auto</literal> (the default),
and the right subdirectory of
<filename>/var/log/journal</filename>
exists, it will be bind mounted
<term><option>-j</option></term>
<listitem><para>Equivalent to
- <option>--link-journal=guest</option>.</para></listitem>
+ <option>--link-journal=try-guest</option>.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--volatile</option><replaceable>=MODE</replaceable></term>
<listitem><para>Boots the container in
- volatile (ephemeral) mode. When no
- mode parameter is passed or when mode
- is specified as <literal>yes</literal>
- full volatile mode is enabled. This
- means the root directory is mounted as
- mostly unpopulated
- <literal>tmpfs</literal> instance, and
+ volatile mode. When no mode parameter
+ is passed or when mode is specified as
+ <literal>yes</literal> full volatile
+ mode is enabled. This means the root
+ directory is mounted as mostly
+ unpopulated <literal>tmpfs</literal>
+ instance, and
<filename>/usr</filename> from the OS
tree is mounted into it, read-only
(the system thus starts up with
changes to the latter are lost on
shutdown). When the mode parameter is
specified as <literal>no</literal>
- (the default) the whole OS tree is made
- available writable.</para>
+ (the default) the whole OS tree is
+ made available writable.</para>
<para>Note that setting this to
<literal>yes</literal> or
<example>
<title>Boot a minimal Fedora distribution in a container</title>
- <programlisting># yum -y --releasever=19 --nogpg --installroot=/srv/mycontainer --disablerepo='*' --enablerepo=fedora install systemd passwd yum fedora-release vim-minimal
+ <programlisting># yum -y --releasever=21 --nogpg --installroot=/srv/mycontainer --disablerepo='*' --enablerepo=fedora install systemd passwd yum fedora-release vim-minimal
# systemd-nspawn -bD /srv/mycontainer</programlisting>
<para>This installs a minimal Fedora distribution into
</example>
<example>
- <title>Boot into a btrfs snapshot of the host system</title>
+ <title>Boot into an ephemeral <literal>btrfs</literal> snapshot of the host system</title>
- <programlisting># btrfs subvolume snapshot / /.tmp
-# systemd-nspawn --private-network -D /.tmp -b</programlisting>
+ <programlisting># systemd-nspawn -D / -xb</programlisting>
<para>This runs a copy of the host system in a
- btrfs snapshot.</para>
+ <literal>btrfs</literal> snapshot which is
+ removed immediately when the container
+ exits. All file system changes made during
+ runtime will be lost on shutdown,
+ hence.</para>
</example>
<example>
<citerefentry project='die-net'><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry project='archlinux'><refentrytitle>pacman</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>btrfs</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</para>
</refsect1>
~ianmdlvl / elogind.git / blobdiff