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diff --git a/man/systemd-nspawn.xml b/man/systemd-nspawn.xml new file mode 100644 index 0000000000..70ebf94e0f --- /dev/null +++ b/man/systemd-nspawn.xml @@ -0,0 +1,190 @@ +<?xml version='1.0'?> <!--*-nxml-*--> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> + +<!-- + This file is part of systemd. + + Copyright 2010 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +--> + +<refentry id="systemd-nspawn"> + + <refentryinfo> + <title>systemd-nspawn</title> + <productname>systemd</productname> + + <authorgroup> + <author> + <contrib>Developer</contrib> + <firstname>Lennart</firstname> + <surname>Poettering</surname> + <email>lennart@poettering.net</email> + </author> + </authorgroup> + </refentryinfo> + + <refmeta> + <refentrytitle>systemd-nspawn</refentrytitle> + <manvolnum>1</manvolnum> + </refmeta> + + <refnamediv> + <refname>systemd-nspawn</refname> + <refpurpose>Spawn a namespace container for debugging, testing and building</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <cmdsynopsis> + <command>systemd-nspawn <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt">COMMAND</arg> <arg choice="opt" rep="repeat">ARGS</arg></command> + </cmdsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><command>systemd-nspawn</command> may be used to + run a command or OS in a light-weight namespace + container. In many ways it is similar to + <citerefentry><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + but more powerful since it fully virtualizes the file + system hierachy, as well as the process tree, the + various IPC subsystems and the host and domain + name.</para> + + <para><command>systemd-nspawn</command> limits access + to various kernel interfaces in the container to + read-only, such as <filename>/sys</filename>, + <filename>/proc/sys</filename> or + <filename>/selinux</filename>. Network interfaces and + the system clock may not be changed from within the + container. Device nodes may not be created. The host + system cannot be rebooted and kernel modules may not + be loaded from within the container.</para> + + <para>Note that even though these security precautions + are taken <command>systemd-nspawn</command> is not + suitable for secure container setups. Many of the + security features may be circumvented and are hence + primarily useful to avoid accidental changes to the + host system from the container. The intended use of + this program is debugging and testing as well as + building of packages, distributions and software + involved with boot and systems management.</para> + + <para>In contrast to + <citerefentry><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry> + <command>systemd-nspawn</command> may be used to boot + full Linux-based operating systems in a + container.</para> + + <para>Use a tool like + <citerefentry><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry> or <citerefentry><refentrytitle>mock</refentrytitle><manvolnum>1</manvolnum></citerefentry> + to set up an OS directory tree suitable as file system + hierarchy for <command>systemd-nspawn</command> containers.</para> + + <para>Note that <command>systemd-nspawn</command> will + mount file systems private to the container to + <filename>/dev</filename>, + <filename>/dev/.run</filename> and similar. These will + not be visible outside of the container, and their + contents will be lost when the container exits.</para> + + <para>Note that running two + <command>systemd-nspawn</command> containers from the + same directory tree will not make processes in them + see each other. The PID namespace seperation of the + two containers is complete and the containers will + share very few runtime objects except for the + underlying file system.</para> + </refsect1> + + <refsect1> + <title>Options</title> + + <para>If no arguments are passed the container is set + up and a shell started in it, otherwise the passed + command and arguments are executed in it. The + following options are understood:</para> + + <variablelist> + <varlistentry> + <term><option>--help</option></term> + + <listitem><para>Prints a short help + text and exits.</para></listitem> + </varlistentry> + + <varlistentry> + <term><option>--directory=</option></term> + <term><option>--D</option></term> + + <listitem><para>Directory to use as + file system root for the namespace + container. If omitted the current + directory will be + used.</para></listitem> + </varlistentry> + + </variablelist> + + </refsect1> + + <refsect1> + <title>Example 1</title> + + <programlisting># debootstrap --arch=amd64 unstable debian-tree/ +# systemd-nspawn -D debian-tree/</programlisting> + + <para>This installs a minimal Debian unstable + distribution into the directory + <filename>debian-tree/</filename> and then spawns a + shell in a namespace container in it.</para> + + </refsect1> + + <refsect1> + <title>Example 2</title> + + <programlisting># mock --init +# systemd-nspawn -D /var/lib/mock/fedora-rawhide-x86_64/root/ /bin/systemd systemd.log_level=debug</programlisting> + + <para>This installs a minimal Fedora distribution into + a subdirectory of <filename>/var/lib/mock/</filename> + and then boots an OS in a namespace container in it, + with systemd as init system, configured for debug + logging.</para> + + </refsect1> + + <refsect1> + <title>Exit status</title> + + <para>The exit code of the program executed in the + container is returned.</para> + </refsect1> + + <refsect1> + <title>See Also</title> + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry> + <citerefentry><refentrytitle>mock</refentrytitle><manvolnum>1</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |