mirror of
https://github.com/systemd/systemd.git
synced 2024-11-24 02:33:36 +08:00
339 lines
16 KiB
XML
339 lines
16 KiB
XML
<?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 Lesser General Public License as published by
|
|
the Free Software Foundation; either version 2.1 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser 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 hierarchy, 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>/sys/fs/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>yum</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
or
|
|
<citerefentry><refentrytitle>debootstrap</refentrytitle><manvolnum>8</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>/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 separation of the
|
|
two containers is complete and the containers will
|
|
share very few runtime objects except for the
|
|
underlying file system.</para>
|
|
|
|
<para><command>systemd-nspawn</command> implements the
|
|
<ulink
|
|
url="http://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container
|
|
Interface</ulink> specification.</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>
|
|
<term><option>-h</option></term>
|
|
|
|
<listitem><para>Prints a short help
|
|
text and exits.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>--version</option></term>
|
|
|
|
<listitem><para>Prints a version string
|
|
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>
|
|
|
|
<varlistentry>
|
|
<term><option>--boot</option></term>
|
|
<term><option>-b</option></term>
|
|
|
|
<listitem><para>Automatically search
|
|
for an init binary and invoke it
|
|
instead of a shell or a user supplied
|
|
program.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>--user=</option></term>
|
|
<term><option>-u</option></term>
|
|
|
|
<listitem><para>Run the command
|
|
under specified user, create home
|
|
directory and cd into it. As rest
|
|
of systemd-nspawn, this is not
|
|
the security feature and limits
|
|
against accidental changes only.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>--uuid=</option></term>
|
|
|
|
<listitem><para>Set the specified uuid
|
|
for the container. The init system
|
|
will initialize
|
|
<filename>/etc/machine-id</filename>
|
|
from this if this file is not set yet.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>--controllers=</option></term>
|
|
<term><option>-C</option></term>
|
|
|
|
<listitem><para>Makes the container appear in
|
|
other hierarchies than the name=systemd:/ one.
|
|
Takes a comma-separated list of controllers.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>--private-network</option></term>
|
|
|
|
<listitem><para>Turn off networking in
|
|
the container. This makes all network
|
|
interfaces unavailable in the
|
|
container, with the exception of the
|
|
loopback device.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>--read-only</option></term>
|
|
|
|
<listitem><para>Mount the root file
|
|
system read only for the
|
|
container.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>--capability=</option></term>
|
|
|
|
<listitem><para>List one or more
|
|
additional capabilities to grant the
|
|
container. Takes a comma separated
|
|
list of capability names, see
|
|
<citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
for more information. Note that the
|
|
following capabilities will be
|
|
granted in any way: CAP_CHOWN,
|
|
CAP_DAC_OVERRIDE, CAP_DAC_READ_SEARCH,
|
|
CAP_FOWNER, CAP_FSETID, CAP_IPC_OWNER,
|
|
CAP_KILL, CAP_LEASE,
|
|
CAP_LINUX_IMMUTABLE,
|
|
CAP_NET_BIND_SERVICE,
|
|
CAP_NET_BROADCAST, CAP_NET_RAW,
|
|
CAP_SETGID, CAP_SETFCAP, CAP_SETPCAP,
|
|
CAP_SETUID, CAP_SYS_ADMIN,
|
|
CAP_SYS_CHROOT, CAP_SYS_NICE,
|
|
CAP_SYS_PTRACE, CAP_SYS_TTY_CONFIG,
|
|
CAP_SYS_RESOURCE, CAP_SYS_BOOT.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>--link-journal=</option></term>
|
|
|
|
<listitem><para>Control whether the
|
|
container's journal shall be made
|
|
visible to the host system. If enabled
|
|
allows viewing the container's journal
|
|
files from the host (but not vice
|
|
versa). Takes one of
|
|
<literal>no</literal>,
|
|
<literal>host</literal>,
|
|
<literal>guest</literal>,
|
|
<literal>auto</literal>. If
|
|
<literal>no</literal>, the journal is
|
|
not linked. If <literal>host</literal>,
|
|
the journal files are stored on the
|
|
host file system (beneath
|
|
<filename>/var/log/journal/<machine-id></filename>)
|
|
and the subdirectory is bind-mounted
|
|
into the container at the same
|
|
location. If <literal>guest</literal>,
|
|
the journal files are stored on the
|
|
guest file system (beneath
|
|
<filename>/var/log/journal/<machine-id></filename>)
|
|
and the subdirectory is symlinked into the host
|
|
at the same location. If
|
|
<literal>auto</literal> (the default),
|
|
and the right subdirectory of
|
|
<filename>/var/log/journal</filename>
|
|
exists, it will be bind mounted
|
|
into the container. If the
|
|
subdirectory doesn't exist, no
|
|
linking is performed. Effectively,
|
|
booting a container once with
|
|
<literal>guest</literal> or
|
|
<literal>host</literal> will link the
|
|
journal persistently if further on
|
|
the default of <literal>auto</literal>
|
|
is used.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>-j</option></term>
|
|
|
|
<listitem><para>Equivalent to
|
|
<option>--link-journal=guest</option>.</para></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Example 1</title>
|
|
|
|
<programlisting># yum --releasever=17 --nogpgcheck --installroot ~/fedora-tree/ install yum passwd vim-minimal rootfiles systemd
|
|
# systemd-nspawn -D ~/fedora-tree /usr/lib/systemd/systemd</programlisting>
|
|
|
|
<para>This installs a minimal Fedora distribution into
|
|
the directory <filename>~/fedora-tree/</filename>
|
|
and then boots an OS in a namespace container in it,
|
|
with systemd as init system.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Example 2</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>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>yum</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|