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f757855e | 1 | <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> |
8f7a3c14 | 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" |
12b42c76 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
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4 | |
5 | <!-- | |
6 | This file is part of systemd. | |
7 | ||
8 | Copyright 2010 Lennart Poettering | |
9 | ||
10 | systemd is free software; you can redistribute it and/or modify it | |
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11 | under the terms of the GNU Lesser General Public License as published by |
12 | the Free Software Foundation; either version 2.1 of the License, or | |
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13 | (at your option) any later version. |
14 | ||
15 | systemd is distributed in the hope that it will be useful, but | |
16 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
5430f7f2 | 18 | Lesser General Public License for more details. |
8f7a3c14 | 19 | |
5430f7f2 | 20 | You should have received a copy of the GNU Lesser General Public License |
8f7a3c14 LP |
21 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
22 | --> | |
23 | ||
dfdebb1b | 24 | <refentry id="systemd-nspawn" |
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25 | xmlns:xi="http://www.w3.org/2001/XInclude"> |
26 | ||
27 | <refentryinfo> | |
28 | <title>systemd-nspawn</title> | |
29 | <productname>systemd</productname> | |
30 | ||
31 | <authorgroup> | |
32 | <author> | |
33 | <contrib>Developer</contrib> | |
34 | <firstname>Lennart</firstname> | |
35 | <surname>Poettering</surname> | |
36 | <email>lennart@poettering.net</email> | |
37 | </author> | |
38 | </authorgroup> | |
39 | </refentryinfo> | |
40 | ||
41 | <refmeta> | |
42 | <refentrytitle>systemd-nspawn</refentrytitle> | |
43 | <manvolnum>1</manvolnum> | |
44 | </refmeta> | |
45 | ||
46 | <refnamediv> | |
47 | <refname>systemd-nspawn</refname> | |
48 | <refpurpose>Spawn a namespace container for debugging, testing and building</refpurpose> | |
49 | </refnamediv> | |
50 | ||
51 | <refsynopsisdiv> | |
52 | <cmdsynopsis> | |
53 | <command>systemd-nspawn</command> | |
54 | <arg choice="opt" rep="repeat">OPTIONS</arg> | |
55 | <arg choice="opt"><replaceable>COMMAND</replaceable> | |
56 | <arg choice="opt" rep="repeat">ARGS</arg> | |
57 | </arg> | |
58 | </cmdsynopsis> | |
59 | <cmdsynopsis> | |
60 | <command>systemd-nspawn</command> | |
4447e799 | 61 | <arg choice="plain">--boot</arg> |
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62 | <arg choice="opt" rep="repeat">OPTIONS</arg> |
63 | <arg choice="opt" rep="repeat">ARGS</arg> | |
64 | </cmdsynopsis> | |
65 | </refsynopsisdiv> | |
66 | ||
67 | <refsect1> | |
68 | <title>Description</title> | |
69 | ||
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70 | <para><command>systemd-nspawn</command> may be used to run a command or OS in a light-weight namespace |
71 | container. In many ways it is similar to <citerefentry | |
72 | project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry>, but more powerful | |
73 | since it fully virtualizes the file system hierarchy, as well as the process tree, the various IPC subsystems and | |
74 | the host and domain name.</para> | |
75 | ||
5164c3b4 | 76 | <para><command>systemd-nspawn</command> may be invoked on any directory tree containing an operating system tree, |
b09c0bba | 77 | using the <option>--directory=</option> command line option. By using the <option>--machine=</option> option an OS |
5164c3b4 | 78 | tree is automatically searched for in a couple of locations, most importantly in |
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79 | <filename>/var/lib/machines</filename>, the suggested directory to place container images installed on the |
80 | system.</para> | |
81 | ||
82 | <para>In contrast to <citerefentry | |
83 | project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry> <command>systemd-nspawn</command> | |
84 | may be used to boot full Linux-based operating systems in a container.</para> | |
85 | ||
86 | <para><command>systemd-nspawn</command> limits access to various kernel interfaces in the container to read-only, | |
87 | such as <filename>/sys</filename>, <filename>/proc/sys</filename> or <filename>/sys/fs/selinux</filename>. The | |
88 | host's network interfaces and the system clock may not be changed from within the container. Device nodes may not | |
89 | be created. The host system cannot be rebooted and kernel modules may not be loaded from within the | |
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90 | container.</para> |
91 | ||
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92 | <para>Use a tool like <citerefentry |
93 | project='mankier'><refentrytitle>dnf</refentrytitle><manvolnum>8</manvolnum></citerefentry>, <citerefentry | |
94 | project='die-net'><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>, or | |
95 | <citerefentry project='archlinux'><refentrytitle>pacman</refentrytitle><manvolnum>8</manvolnum></citerefentry> to | |
96 | set up an OS directory tree suitable as file system hierarchy for <command>systemd-nspawn</command> containers. See | |
97 | the Examples section below for details on suitable invocation of these commands.</para> | |
98 | ||
99 | <para>As a safety check <command>systemd-nspawn</command> will verify the existence of | |
100 | <filename>/usr/lib/os-release</filename> or <filename>/etc/os-release</filename> in the container tree before | |
101 | starting the container (see | |
102 | <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry>). It might be | |
103 | necessary to add this file to the container tree manually if the OS of the container is too old to contain this | |
798d3a52 | 104 | file out-of-the-box.</para> |
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105 | |
106 | <para><command>systemd-nspawn</command> may be invoked directly from the interactive command line or run as system | |
107 | service in the background. In this mode each container instance runs as its own service instance; a default | |
108 | template unit file <filename>systemd-nspawn@.service</filename> is provided to make this easy, taking the container | |
109 | name as instance identifier. Note that different default options apply when <command>systemd-nspawn</command> is | |
6dd6a9c4 | 110 | invoked by the template unit file than interactively on the command line. Most importantly the template unit file |
b09c0bba | 111 | makes use of the <option>--boot</option> which is not the default in case <command>systemd-nspawn</command> is |
6dd6a9c4 | 112 | invoked from the interactive command line. Further differences with the defaults are documented along with the |
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113 | various supported options below.</para> |
114 | ||
115 | <para>The <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> tool may | |
116 | be used to execute a number of operations on containers. In particular it provides easy-to-use commands to run | |
117 | containers as system services using the <filename>systemd-nspawn@.service</filename> template unit | |
118 | file.</para> | |
119 | ||
120 | <para>Along with each container a settings file with the <filename>.nspawn</filename> suffix may exist, containing | |
121 | additional settings to apply when running the container. See | |
122 | <citerefentry><refentrytitle>systemd.nspawn</refentrytitle><manvolnum>5</manvolnum></citerefentry> for | |
123 | details. Settings files override the default options used by the <filename>systemd-nspawn@.service</filename> | |
124 | template unit file, making it usually unnecessary to alter this template file directly.</para> | |
125 | ||
126 | <para>Note that <command>systemd-nspawn</command> will mount file systems private to the container to | |
127 | <filename>/dev</filename>, <filename>/run</filename> and similar. These will not be visible outside of the | |
128 | container, and their contents will be lost when the container exits.</para> | |
129 | ||
130 | <para>Note that running two <command>systemd-nspawn</command> containers from the same directory tree will not make | |
131 | processes in them see each other. The PID namespace separation of the two containers is complete and the containers | |
132 | will share very few runtime objects except for the underlying file system. Use | |
133 | <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s | |
134 | <command>login</command> or <command>shell</command> commands to request an additional login session in a running | |
135 | container.</para> | |
136 | ||
137 | <para><command>systemd-nspawn</command> implements the <ulink | |
138 | url="http://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container Interface</ulink> | |
139 | specification.</para> | |
140 | ||
141 | <para>While running, containers invoked with <command>systemd-nspawn</command> are registered with the | |
142 | <citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>8</manvolnum></citerefentry> service that | |
143 | keeps track of running containers, and provides programming interfaces to interact with them.</para> | |
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144 | </refsect1> |
145 | ||
146 | <refsect1> | |
147 | <title>Options</title> | |
148 | ||
149 | <para>If option <option>-b</option> is specified, the arguments | |
150 | are used as arguments for the init binary. Otherwise, | |
151 | <replaceable>COMMAND</replaceable> specifies the program to launch | |
152 | in the container, and the remaining arguments are used as | |
b09c0bba | 153 | arguments for this program. If <option>--boot</option> is not used and |
ff9b60f3 | 154 | no arguments are specified, a shell is launched in the |
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155 | container.</para> |
156 | ||
157 | <para>The following options are understood:</para> | |
158 | ||
159 | <variablelist> | |
160 | <varlistentry> | |
161 | <term><option>-D</option></term> | |
162 | <term><option>--directory=</option></term> | |
163 | ||
164 | <listitem><para>Directory to use as file system root for the | |
165 | container.</para> | |
166 | ||
167 | <para>If neither <option>--directory=</option>, nor | |
168 | <option>--image=</option> is specified the directory is | |
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169 | determined by searching for a directory named the same as the |
170 | machine name specified with <option>--machine=</option>. See | |
171 | <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
172 | section "Files and Directories" for the precise search path.</para> | |
173 | ||
174 | <para>If neither <option>--directory=</option>, | |
175 | <option>--image=</option>, nor <option>--machine=</option> | |
176 | are specified, the current directory will | |
177 | be used. May not be specified together with | |
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178 | <option>--image=</option>.</para></listitem> |
179 | </varlistentry> | |
180 | ||
181 | <varlistentry> | |
182 | <term><option>--template=</option></term> | |
183 | ||
184 | <listitem><para>Directory or <literal>btrfs</literal> | |
185 | subvolume to use as template for the container's root | |
186 | directory. If this is specified and the container's root | |
187 | directory (as configured by <option>--directory=</option>) | |
188 | does not yet exist it is created as <literal>btrfs</literal> | |
189 | subvolume and populated from this template tree. Ideally, the | |
190 | specified template path refers to the root of a | |
191 | <literal>btrfs</literal> subvolume, in which case a simple | |
192 | copy-on-write snapshot is taken, and populating the root | |
193 | directory is instant. If the specified template path does not | |
194 | refer to the root of a <literal>btrfs</literal> subvolume (or | |
195 | not even to a <literal>btrfs</literal> file system at all), | |
196 | the tree is copied, which can be substantially more | |
197 | time-consuming. Note that if this option is used the | |
198 | container's root directory (in contrast to the template | |
199 | directory!) must be located on a <literal>btrfs</literal> file | |
200 | system, so that the <literal>btrfs</literal> subvolume may be | |
201 | created. May not be specified together with | |
202 | <option>--image=</option> or | |
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203 | <option>--ephemeral</option>.</para> |
204 | ||
205 | <para>Note that this switch leaves host name, machine ID and | |
206 | all other settings that could identify the instance | |
207 | unmodified.</para></listitem> | |
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208 | </varlistentry> |
209 | ||
210 | <varlistentry> | |
211 | <term><option>-x</option></term> | |
212 | <term><option>--ephemeral</option></term> | |
213 | ||
214 | <listitem><para>If specified, the container is run with a | |
215 | temporary <literal>btrfs</literal> snapshot of its root | |
216 | directory (as configured with <option>--directory=</option>), | |
217 | that is removed immediately when the container terminates. | |
218 | This option is only supported if the root file system is | |
219 | <literal>btrfs</literal>. May not be specified together with | |
220 | <option>--image=</option> or | |
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221 | <option>--template=</option>.</para> |
222 | <para>Note that this switch leaves host name, machine ID and | |
223 | all other settings that could identify the instance | |
224 | unmodified.</para></listitem> | |
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225 | </varlistentry> |
226 | ||
227 | <varlistentry> | |
228 | <term><option>-i</option></term> | |
229 | <term><option>--image=</option></term> | |
230 | ||
231 | <listitem><para>Disk image to mount the root directory for the | |
232 | container from. Takes a path to a regular file or to a block | |
233 | device node. The file or block device must contain | |
234 | either:</para> | |
235 | ||
236 | <itemizedlist> | |
237 | <listitem><para>An MBR partition table with a single | |
238 | partition of type 0x83 that is marked | |
239 | bootable.</para></listitem> | |
240 | ||
241 | <listitem><para>A GUID partition table (GPT) with a single | |
242 | partition of type | |
243 | 0fc63daf-8483-4772-8e79-3d69d8477de4.</para></listitem> | |
244 | ||
245 | <listitem><para>A GUID partition table (GPT) with a marked | |
246 | root partition which is mounted as the root directory of the | |
247 | container. Optionally, GPT images may contain a home and/or | |
248 | a server data partition which are mounted to the appropriate | |
249 | places in the container. All these partitions must be | |
250 | identified by the partition types defined by the <ulink | |
251 | url="http://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/">Discoverable | |
252 | Partitions Specification</ulink>.</para></listitem> | |
253 | </itemizedlist> | |
254 | ||
255 | <para>Any other partitions, such as foreign partitions, swap | |
256 | partitions or EFI system partitions are not mounted. May not | |
257 | be specified together with <option>--directory=</option>, | |
258 | <option>--template=</option> or | |
259 | <option>--ephemeral</option>.</para></listitem> | |
260 | </varlistentry> | |
261 | ||
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262 | <varlistentry> |
263 | <term><option>-a</option></term> | |
264 | <term><option>--as-pid2</option></term> | |
265 | ||
266 | <listitem><para>Invoke the shell or specified program as process ID (PID) 2 instead of PID 1 (init). By | |
267 | default, if neither this option nor <option>--boot</option> is used, the selected binary is run as process with | |
268 | PID 1, a mode only suitable for programs that are aware of the special semantics that the process with PID 1 | |
269 | has on UNIX. For example, it needs to reap all processes reparented to it, and should implement | |
270 | <command>sysvinit</command> compatible signal handling (specifically: it needs to reboot on SIGINT, reexecute | |
271 | on SIGTERM, reload configuration on SIGHUP, and so on). With <option>--as-pid2</option> a minimal stub init | |
272 | process is run as PID 1 and the selected binary is executed as PID 2 (and hence does not need to implement any | |
273 | special semantics). The stub init process will reap processes as necessary and react appropriately to | |
274 | signals. It is recommended to use this mode to invoke arbitrary commands in containers, unless they have been | |
275 | modified to run correctly as PID 1. Or in other words: this switch should be used for pretty much all commands, | |
276 | except when the command refers to an init or shell implementation, as these are generally capable of running | |
a6b5216c | 277 | correctly as PID 1. This option may not be combined with <option>--boot</option>.</para> |
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278 | </listitem> |
279 | </varlistentry> | |
280 | ||
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281 | <varlistentry> |
282 | <term><option>-b</option></term> | |
283 | <term><option>--boot</option></term> | |
284 | ||
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285 | <listitem><para>Automatically search for an init binary and invoke it as PID 1, instead of a shell or a user |
286 | supplied program. If this option is used, arguments specified on the command line are used as arguments for the | |
a6b5216c | 287 | init binary. This option may not be combined with <option>--as-pid2</option>.</para> |
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288 | |
289 | <para>The following table explains the different modes of invocation and relationship to | |
290 | <option>--as-pid2</option> (see above):</para> | |
291 | ||
292 | <table> | |
293 | <title>Invocation Mode</title> | |
294 | <tgroup cols='2' align='left' colsep='1' rowsep='1'> | |
295 | <colspec colname="switch" /> | |
296 | <colspec colname="explanation" /> | |
297 | <thead> | |
298 | <row> | |
299 | <entry>Switch</entry> | |
300 | <entry>Explanation</entry> | |
301 | </row> | |
302 | </thead> | |
303 | <tbody> | |
304 | <row> | |
305 | <entry>Neither <option>--as-pid2</option> nor <option>--boot</option> specified</entry> | |
4447e799 | 306 | <entry>The passed parameters are interpreted as the command line, which is executed as PID 1 in the container.</entry> |
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307 | </row> |
308 | ||
309 | <row> | |
310 | <entry><option>--as-pid2</option> specified</entry> | |
4447e799 | 311 | <entry>The passed parameters are interpreted as the command line, which is executed as PID 2 in the container. A stub init process is run as PID 1.</entry> |
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312 | </row> |
313 | ||
314 | <row> | |
315 | <entry><option>--boot</option> specified</entry> | |
316 | <entry>An init binary as automatically searched and run as PID 1 in the container. The passed parameters are used as invocation parameters for this process.</entry> | |
317 | </row> | |
318 | ||
319 | </tbody> | |
320 | </tgroup> | |
321 | </table> | |
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322 | |
323 | <para>Note that <option>--boot</option> is the default mode of operation if the | |
324 | <filename>systemd-nspawn@.service</filename> template unit file is used.</para> | |
7732f92b | 325 | </listitem> |
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326 | </varlistentry> |
327 | ||
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328 | <varlistentry> |
329 | <term><option>--chdir=</option></term> | |
330 | ||
331 | <listitem><para>Change to the specified working directory before invoking the process in the container. Expects | |
332 | an absolute path in the container's file system namespace.</para></listitem> | |
333 | </varlistentry> | |
334 | ||
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335 | <varlistentry> |
336 | <term><option>-u</option></term> | |
337 | <term><option>--user=</option></term> | |
338 | ||
339 | <listitem><para>After transitioning into the container, change | |
340 | to the specified user-defined in the container's user | |
341 | database. Like all other systemd-nspawn features, this is not | |
342 | a security feature and provides protection against accidental | |
343 | destructive operations only.</para></listitem> | |
344 | </varlistentry> | |
345 | ||
346 | <varlistentry> | |
347 | <term><option>-M</option></term> | |
348 | <term><option>--machine=</option></term> | |
349 | ||
350 | <listitem><para>Sets the machine name for this container. This | |
351 | name may be used to identify this container during its runtime | |
352 | (for example in tools like | |
353 | <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
354 | and similar), and is used to initialize the container's | |
355 | hostname (which the container can choose to override, | |
356 | however). If not specified, the last component of the root | |
357 | directory path of the container is used, possibly suffixed | |
358 | with a random identifier in case <option>--ephemeral</option> | |
359 | mode is selected. If the root directory selected is the host's | |
360 | root directory the host's hostname is used as default | |
361 | instead.</para></listitem> | |
362 | </varlistentry> | |
363 | ||
364 | <varlistentry> | |
365 | <term><option>--uuid=</option></term> | |
366 | ||
367 | <listitem><para>Set the specified UUID for the container. The | |
368 | init system will initialize | |
369 | <filename>/etc/machine-id</filename> from this if this file is | |
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370 | not set yet. Note that this option takes effect only if |
371 | <filename>/etc/machine-id</filename> in the container is | |
372 | unpopulated.</para></listitem> | |
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373 | </varlistentry> |
374 | ||
375 | <varlistentry> | |
376 | <term><option>--slice=</option></term> | |
377 | ||
378 | <listitem><para>Make the container part of the specified | |
379 | slice, instead of the default | |
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380 | <filename>machine.slice</filename>. This is only applies if |
381 | the machine is run in its own scope unit, i.e. if | |
382 | <option>--keep-unit</option> is not used.</para> | |
383 | </listitem> | |
384 | </varlistentry> | |
385 | ||
386 | <varlistentry> | |
387 | <term><option>--property=</option></term> | |
388 | ||
389 | <listitem><para>Set a unit property on the scope unit to | |
390 | register for the machine. This only applies if the machine is | |
391 | run in its own scope unit, i.e. if | |
392 | <option>--keep-unit</option> is not used. Takes unit property | |
393 | assignments in the same format as <command>systemctl | |
394 | set-property</command>. This is useful to set memory limits | |
395 | and similar for machines.</para> | |
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396 | </listitem> |
397 | </varlistentry> | |
398 | ||
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399 | <varlistentry> |
400 | <term><option>--private-users=</option></term> | |
401 | ||
d2e5535f LP |
402 | <listitem><para>Controls user namespacing. If enabled, the container will run with its own private set of UNIX |
403 | user and group ids (UIDs and GIDs). This involves mapping the private UIDs/GIDs used in the container (starting | |
404 | with the container's root user 0 and up) to a range of UIDs/GIDs on the host that are not used for other | |
405 | purposes (usually in the range beyond the host's UID/GID 65536). The parameter may be specified as follows:</para> | |
406 | ||
407 | <orderedlist> | |
2dd67817 | 408 | <listitem><para>If one or two colon-separated numbers are specified, user namespacing is turned on. The first |
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409 | parameter specifies the first host UID/GID to assign to the container, the second parameter specifies the |
410 | number of host UIDs/GIDs to assign to the container. If the second parameter is omitted, 65536 UIDs/GIDs are | |
411 | assigned.</para></listitem> | |
412 | ||
413 | <listitem><para>If the parameter is omitted, or true, user namespacing is turned on. The UID/GID range to | |
414 | use is determined automatically from the file ownership of the root directory of the container's directory | |
415 | tree. To use this option, make sure to prepare the directory tree in advance, and ensure that all files and | |
416 | directories in it are owned by UIDs/GIDs in the range you'd like to use. Also, make sure that used file ACLs | |
417 | exclusively reference UIDs/GIDs in the appropriate range. If this mode is used the number of UIDs/GIDs | |
418 | assigned to the container for use is 65536, and the UID/GID of the root directory must be a multiple of | |
419 | 65536.</para></listitem> | |
420 | ||
421 | <listitem><para>If the parameter is false, user namespacing is turned off. This is the default.</para> | |
422 | </listitem> | |
423 | ||
424 | <listitem><para>The special value <literal>pick</literal> turns on user namespacing. In this case the UID/GID | |
425 | range is automatically chosen. As first step, the file owner of the root directory of the container's | |
426 | directory tree is read, and it is checked that it is currently not used by the system otherwise (in | |
427 | particular, that no other container is using it). If this check is successful, the UID/GID range determined | |
2dd67817 | 428 | this way is used, similar to the behavior if "yes" is specified. If the check is not successful (and thus |
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429 | the UID/GID range indicated in the root directory's file owner is already used elsewhere) a new – currently |
430 | unused – UID/GID range of 65536 UIDs/GIDs is randomly chosen between the host UID/GIDs of 524288 and | |
431 | 1878982656, always starting at a multiple of 65536. This setting implies | |
432 | <option>--private-users-chown</option> (see below), which has the effect that the files and directories in | |
433 | the container's directory tree will be owned by the appropriate users of the range picked. Using this option | |
2dd67817 | 434 | makes user namespace behavior fully automatic. Note that the first invocation of a previously unused |
ae209204 ZJS |
435 | container image might result in picking a new UID/GID range for it, and thus in the (possibly expensive) file |
436 | ownership adjustment operation. However, subsequent invocations of the container will be cheap (unless of | |
437 | course the picked UID/GID range is assigned to a different use by then).</para></listitem> | |
d2e5535f LP |
438 | </orderedlist> |
439 | ||
440 | <para>It is recommended to assign at least 65536 UIDs/GIDs to each container, so that the usable UID/GID range in the | |
441 | container covers 16 bit. For best security, do not assign overlapping UID/GID ranges to multiple containers. It is | |
442 | hence a good idea to use the upper 16 bit of the host 32-bit UIDs/GIDs as container identifier, while the lower 16 | |
2dd67817 | 443 | bit encode the container UID/GID used. This is in fact the behavior enforced by the |
d2e5535f LP |
444 | <option>--private-users=pick</option> option.</para> |
445 | ||
446 | <para>When user namespaces are used, the GID range assigned to each container is always chosen identical to the | |
447 | UID range.</para> | |
448 | ||
449 | <para>In most cases, using <option>--private-users=pick</option> is the recommended option as it enhances | |
450 | container security massively and operates fully automatically in most cases.</para> | |
451 | ||
452 | <para>Note that the picked UID/GID range is not written to <filename>/etc/passwd</filename> or | |
453 | <filename>/etc/group</filename>. In fact, the allocation of the range is not stored persistently anywhere, | |
454 | except in the file ownership of the files and directories of the container.</para></listitem> | |
03cfe0d5 LP |
455 | </varlistentry> |
456 | ||
d2e5535f LP |
457 | <varlistentry> |
458 | <term><option>--private-users-chown</option></term> | |
459 | ||
460 | <listitem><para>If specified, all files and directories in the container's directory tree will adjusted so that | |
461 | they are owned to the appropriate UIDs/GIDs selected for the container (see above). This operation is | |
462 | potentially expensive, as it involves descending and iterating through the full directory tree of the | |
463 | container. Besides actual file ownership, file ACLs are adjusted as well.</para> | |
464 | ||
465 | <para>This option is implied if <option>--private-users=pick</option> is used. This option has no effect if | |
466 | user namespacing is not used.</para></listitem> | |
467 | </varlistentry> | |
03cfe0d5 | 468 | |
6265bde2 ZJS |
469 | <varlistentry> |
470 | <term><option>-U</option></term> | |
471 | ||
472 | <listitem><para>If the kernel supports the user namespaces feature, equivalent to | |
473 | <option>--private-users=pick --private-users-chown</option>, otherwise equivalent to | |
474 | <option>--private-users=no</option>.</para> | |
475 | ||
476 | <para>Note that <option>-U</option> is the default if the | |
477 | <filename>systemd-nspawn@.service</filename> template unit file is used.</para> | |
478 | ||
479 | <para>Note: it is possible to undo the effect of <option>--private-users-chown</option> (or | |
480 | <option>-U</option>) on the file system by redoing the operation with the first UID of 0:</para> | |
481 | ||
482 | <programlisting>systemd-nspawn … --private-users=0 --private-users-chown</programlisting> | |
483 | </listitem> | |
484 | </varlistentry> | |
485 | ||
798d3a52 ZJS |
486 | <varlistentry> |
487 | <term><option>--private-network</option></term> | |
488 | ||
489 | <listitem><para>Disconnect networking of the container from | |
490 | the host. This makes all network interfaces unavailable in the | |
491 | container, with the exception of the loopback device and those | |
492 | specified with <option>--network-interface=</option> and | |
493 | configured with <option>--network-veth</option>. If this | |
494 | option is specified, the CAP_NET_ADMIN capability will be | |
495 | added to the set of capabilities the container retains. The | |
496 | latter may be disabled by using | |
497 | <option>--drop-capability=</option>.</para></listitem> | |
498 | </varlistentry> | |
499 | ||
500 | <varlistentry> | |
501 | <term><option>--network-interface=</option></term> | |
502 | ||
503 | <listitem><para>Assign the specified network interface to the | |
504 | container. This will remove the specified interface from the | |
505 | calling namespace and place it in the container. When the | |
506 | container terminates, it is moved back to the host namespace. | |
507 | Note that <option>--network-interface=</option> implies | |
508 | <option>--private-network</option>. This option may be used | |
509 | more than once to add multiple network interfaces to the | |
510 | container.</para></listitem> | |
511 | </varlistentry> | |
512 | ||
513 | <varlistentry> | |
514 | <term><option>--network-macvlan=</option></term> | |
515 | ||
516 | <listitem><para>Create a <literal>macvlan</literal> interface | |
517 | of the specified Ethernet network interface and add it to the | |
518 | container. A <literal>macvlan</literal> interface is a virtual | |
519 | interface that adds a second MAC address to an existing | |
520 | physical Ethernet link. The interface in the container will be | |
521 | named after the interface on the host, prefixed with | |
522 | <literal>mv-</literal>. Note that | |
523 | <option>--network-macvlan=</option> implies | |
524 | <option>--private-network</option>. This option may be used | |
525 | more than once to add multiple network interfaces to the | |
526 | container.</para></listitem> | |
527 | </varlistentry> | |
528 | ||
529 | <varlistentry> | |
530 | <term><option>--network-ipvlan=</option></term> | |
531 | ||
532 | <listitem><para>Create an <literal>ipvlan</literal> interface | |
533 | of the specified Ethernet network interface and add it to the | |
534 | container. An <literal>ipvlan</literal> interface is a virtual | |
535 | interface, similar to a <literal>macvlan</literal> interface, | |
536 | which uses the same MAC address as the underlying interface. | |
537 | The interface in the container will be named after the | |
538 | interface on the host, prefixed with <literal>iv-</literal>. | |
539 | Note that <option>--network-ipvlan=</option> implies | |
540 | <option>--private-network</option>. This option may be used | |
541 | more than once to add multiple network interfaces to the | |
542 | container.</para></listitem> | |
543 | </varlistentry> | |
544 | ||
545 | <varlistentry> | |
546 | <term><option>-n</option></term> | |
547 | <term><option>--network-veth</option></term> | |
548 | ||
5e7423ff LP |
549 | <listitem><para>Create a virtual Ethernet link (<literal>veth</literal>) between host and container. The host |
550 | side of the Ethernet link will be available as a network interface named after the container's name (as | |
551 | specified with <option>--machine=</option>), prefixed with <literal>ve-</literal>. The container side of the | |
552 | Ethernet link will be named <literal>host0</literal>. The <option>--network-veth</option> option implies | |
553 | <option>--private-network</option>.</para> | |
554 | ||
555 | <para>Note that | |
556 | <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
557 | includes by default a network file <filename>/usr/lib/systemd/network/80-container-ve.network</filename> | |
558 | matching the host-side interfaces created this way, which contains settings to enable automatic address | |
559 | provisioning on the created virtual link via DHCP, as well as automatic IP routing onto the host's external | |
560 | network interfaces. It also contains <filename>/usr/lib/systemd/network/80-container-host0.network</filename> | |
561 | matching the container-side interface created this way, containing settings to enable client side address | |
562 | assignment via DHCP. In case <filename>systemd-networkd</filename> is running on both the host and inside the | |
563 | container, automatic IP communication from the container to the host is thus available, with further | |
564 | connectivity to the external network.</para> | |
b09c0bba LP |
565 | |
566 | <para>Note that <option>--network-veth</option> is the default if the | |
567 | <filename>systemd-nspawn@.service</filename> template unit file is used.</para> | |
5e7423ff | 568 | </listitem> |
798d3a52 ZJS |
569 | </varlistentry> |
570 | ||
f6d6bad1 LP |
571 | <varlistentry> |
572 | <term><option>--network-veth-extra=</option></term> | |
573 | ||
574 | <listitem><para>Adds an additional virtual Ethernet link | |
575 | between host and container. Takes a colon-separated pair of | |
576 | host interface name and container interface name. The latter | |
577 | may be omitted in which case the container and host sides will | |
578 | be assigned the same name. This switch is independent of | |
ccddd104 | 579 | <option>--network-veth</option>, and — in contrast — may be |
f6d6bad1 LP |
580 | used multiple times, and allows configuration of the network |
581 | interface names. Note that <option>--network-bridge=</option> | |
582 | has no effect on interfaces created with | |
583 | <option>--network-veth-extra=</option>.</para></listitem> | |
584 | </varlistentry> | |
585 | ||
798d3a52 ZJS |
586 | <varlistentry> |
587 | <term><option>--network-bridge=</option></term> | |
588 | ||
5e7423ff LP |
589 | <listitem><para>Adds the host side of the Ethernet link created with <option>--network-veth</option> to the |
590 | specified Ethernet bridge interface. Expects a valid network interface name of a bridge device as | |
591 | argument. Note that <option>--network-bridge=</option> implies <option>--network-veth</option>. If this option | |
592 | is used, the host side of the Ethernet link will use the <literal>vb-</literal> prefix instead of | |
798d3a52 ZJS |
593 | <literal>ve-</literal>.</para></listitem> |
594 | </varlistentry> | |
595 | ||
938d2579 LP |
596 | <varlistentry> |
597 | <term><option>--network-zone=</option></term> | |
598 | ||
599 | <listitem><para>Creates a virtual Ethernet link (<literal>veth</literal>) to the container and adds it to an | |
600 | automatically managed Ethernet bridge interface. The bridge interface is named after the passed argument, | |
601 | prefixed with <literal>vz-</literal>. The bridge interface is automatically created when the first container | |
602 | configured for its name is started, and is automatically removed when the last container configured for its | |
603 | name exits. Hence, each bridge interface configured this way exists only as long as there's at least one | |
604 | container referencing it running. This option is very similar to <option>--network-bridge=</option>, besides | |
605 | this automatic creation/removal of the bridge device.</para> | |
606 | ||
607 | <para>This setting makes it easy to place multiple related containers on a common, virtual Ethernet-based | |
608 | broadcast domain, here called a "zone". Each container may only be part of one zone, but each zone may contain | |
609 | any number of containers. Each zone is referenced by its name. Names may be chosen freely (as long as they form | |
610 | valid network interface names when prefixed with <literal>vz-</literal>), and it is sufficient to pass the same | |
611 | name to the <option>--network-zones=</option> switch of the various concurrently running containers to join | |
612 | them in one zone.</para> | |
613 | ||
614 | <para>Note that | |
615 | <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
616 | includes by default a network file <filename>/usr/lib/systemd/network/80-container-vz.network</filename> | |
617 | matching the bridge interfaces created this way, which contains settings to enable automatic address | |
618 | provisioning on the created virtual network via DHCP, as well as automatic IP routing onto the host's external | |
619 | network interfaces. Using <option>--network-zone=</option> is hence in most cases fully automatic and | |
620 | sufficient to connect multiple local containers in a joined broadcast domain to the host, with further | |
621 | connectivity to the external network.</para> | |
622 | </listitem> | |
623 | </varlistentry> | |
624 | ||
798d3a52 ZJS |
625 | <varlistentry> |
626 | <term><option>-p</option></term> | |
627 | <term><option>--port=</option></term> | |
628 | ||
629 | <listitem><para>If private networking is enabled, maps an IP | |
630 | port on the host onto an IP port on the container. Takes a | |
631 | protocol specifier (either <literal>tcp</literal> or | |
632 | <literal>udp</literal>), separated by a colon from a host port | |
633 | number in the range 1 to 65535, separated by a colon from a | |
634 | container port number in the range from 1 to 65535. The | |
635 | protocol specifier and its separating colon may be omitted, in | |
636 | which case <literal>tcp</literal> is assumed. The container | |
7c918141 | 637 | port number and its colon may be omitted, in which case the |
798d3a52 | 638 | same port as the host port is implied. This option is only |
a8eaaee7 | 639 | supported if private networking is used, such as with |
938d2579 | 640 | <option>--network-veth</option>, <option>--network-zone=</option> |
798d3a52 ZJS |
641 | <option>--network-bridge=</option>.</para></listitem> |
642 | </varlistentry> | |
643 | ||
644 | <varlistentry> | |
645 | <term><option>-Z</option></term> | |
646 | <term><option>--selinux-context=</option></term> | |
647 | ||
648 | <listitem><para>Sets the SELinux security context to be used | |
649 | to label processes in the container.</para> | |
650 | </listitem> | |
651 | </varlistentry> | |
652 | ||
653 | <varlistentry> | |
654 | <term><option>-L</option></term> | |
655 | <term><option>--selinux-apifs-context=</option></term> | |
656 | ||
657 | <listitem><para>Sets the SELinux security context to be used | |
658 | to label files in the virtual API file systems in the | |
659 | container.</para> | |
660 | </listitem> | |
661 | </varlistentry> | |
662 | ||
663 | <varlistentry> | |
664 | <term><option>--capability=</option></term> | |
665 | ||
666 | <listitem><para>List one or more additional capabilities to | |
667 | grant the container. Takes a comma-separated list of | |
668 | capability names, see | |
669 | <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
670 | for more information. Note that the following capabilities | |
671 | will be granted in any way: CAP_CHOWN, CAP_DAC_OVERRIDE, | |
672 | CAP_DAC_READ_SEARCH, CAP_FOWNER, CAP_FSETID, CAP_IPC_OWNER, | |
673 | CAP_KILL, CAP_LEASE, CAP_LINUX_IMMUTABLE, | |
674 | CAP_NET_BIND_SERVICE, CAP_NET_BROADCAST, CAP_NET_RAW, | |
675 | CAP_SETGID, CAP_SETFCAP, CAP_SETPCAP, CAP_SETUID, | |
676 | CAP_SYS_ADMIN, CAP_SYS_CHROOT, CAP_SYS_NICE, CAP_SYS_PTRACE, | |
677 | CAP_SYS_TTY_CONFIG, CAP_SYS_RESOURCE, CAP_SYS_BOOT, | |
678 | CAP_AUDIT_WRITE, CAP_AUDIT_CONTROL. Also CAP_NET_ADMIN is | |
679 | retained if <option>--private-network</option> is specified. | |
680 | If the special value <literal>all</literal> is passed, all | |
681 | capabilities are retained.</para></listitem> | |
682 | </varlistentry> | |
683 | ||
684 | <varlistentry> | |
685 | <term><option>--drop-capability=</option></term> | |
686 | ||
687 | <listitem><para>Specify one or more additional capabilities to | |
688 | drop for the container. This allows running the container with | |
689 | fewer capabilities than the default (see | |
690 | above).</para></listitem> | |
691 | </varlistentry> | |
692 | ||
c6c8f6e2 LP |
693 | <varlistentry> |
694 | <term><option>--kill-signal=</option></term> | |
695 | ||
696 | <listitem><para>Specify the process signal to send to the | |
697 | container's PID 1 when nspawn itself receives SIGTERM, in | |
698 | order to trigger an orderly shutdown of the | |
699 | container. Defaults to SIGRTMIN+3 if <option>--boot</option> | |
700 | is used (on systemd-compatible init systems SIGRTMIN+3 | |
b3969f73 PA |
701 | triggers an orderly shutdown). For a list of valid signals, see |
702 | <citerefentry project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para></listitem> | |
c6c8f6e2 LP |
703 | </varlistentry> |
704 | ||
798d3a52 ZJS |
705 | <varlistentry> |
706 | <term><option>--link-journal=</option></term> | |
707 | ||
708 | <listitem><para>Control whether the container's journal shall | |
709 | be made visible to the host system. If enabled, allows viewing | |
710 | the container's journal files from the host (but not vice | |
711 | versa). Takes one of <literal>no</literal>, | |
712 | <literal>host</literal>, <literal>try-host</literal>, | |
713 | <literal>guest</literal>, <literal>try-guest</literal>, | |
714 | <literal>auto</literal>. If <literal>no</literal>, the journal | |
715 | is not linked. If <literal>host</literal>, the journal files | |
716 | are stored on the host file system (beneath | |
717 | <filename>/var/log/journal/<replaceable>machine-id</replaceable></filename>) | |
718 | and the subdirectory is bind-mounted into the container at the | |
719 | same location. If <literal>guest</literal>, the journal files | |
720 | are stored on the guest file system (beneath | |
721 | <filename>/var/log/journal/<replaceable>machine-id</replaceable></filename>) | |
722 | and the subdirectory is symlinked into the host at the same | |
723 | location. <literal>try-host</literal> and | |
724 | <literal>try-guest</literal> do the same but do not fail if | |
2dd67817 | 725 | the host does not have persistent journaling enabled. If |
798d3a52 ZJS |
726 | <literal>auto</literal> (the default), and the right |
727 | subdirectory of <filename>/var/log/journal</filename> exists, | |
728 | it will be bind mounted into the container. If the | |
729 | subdirectory does not exist, no linking is performed. | |
730 | Effectively, booting a container once with | |
731 | <literal>guest</literal> or <literal>host</literal> will link | |
732 | the journal persistently if further on the default of | |
b09c0bba LP |
733 | <literal>auto</literal> is used.</para> |
734 | ||
735 | <para>Note that <option>--link-journal=try-guest</option> is the default if the | |
736 | <filename>systemd-nspawn@.service</filename> template unit file is used.</para></listitem> | |
798d3a52 ZJS |
737 | </varlistentry> |
738 | ||
739 | <varlistentry> | |
740 | <term><option>-j</option></term> | |
741 | ||
742 | <listitem><para>Equivalent to | |
743 | <option>--link-journal=try-guest</option>.</para></listitem> | |
744 | </varlistentry> | |
745 | ||
746 | <varlistentry> | |
747 | <term><option>--read-only</option></term> | |
748 | ||
749 | <listitem><para>Mount the root file system read-only for the | |
750 | container.</para></listitem> | |
751 | </varlistentry> | |
752 | ||
753 | <varlistentry> | |
754 | <term><option>--bind=</option></term> | |
755 | <term><option>--bind-ro=</option></term> | |
756 | ||
757 | <listitem><para>Bind mount a file or directory from the host | |
b938cb90 | 758 | into the container. Takes one of: a path argument — in which |
798d3a52 | 759 | case the specified path will be mounted from the host to the |
b938cb90 JE |
760 | same path in the container —, or a colon-separated pair of |
761 | paths — in which case the first specified path is the source | |
798d3a52 | 762 | in the host, and the second path is the destination in the |
b938cb90 JE |
763 | container —, or a colon-separated triple of source path, |
764 | destination path and mount options. Mount options are | |
765 | comma-separated and currently, only "rbind" and "norbind" | |
766 | are allowed. Defaults to "rbind". Backslash escapes are interpreted, so | |
8ef24e7a RM |
767 | <literal>\:</literal> may be used to embed colons in either path. |
768 | This option may be specified multiple times for | |
64b282ef LP |
769 | creating multiple independent bind mount points. The |
770 | <option>--bind-ro=</option> option creates read-only bind | |
771 | mounts.</para></listitem> | |
798d3a52 ZJS |
772 | </varlistentry> |
773 | ||
774 | <varlistentry> | |
775 | <term><option>--tmpfs=</option></term> | |
776 | ||
777 | <listitem><para>Mount a tmpfs file system into the container. | |
778 | Takes a single absolute path argument that specifies where to | |
779 | mount the tmpfs instance to (in which case the directory | |
780 | access mode will be chosen as 0755, owned by root/root), or | |
781 | optionally a colon-separated pair of path and mount option | |
b938cb90 | 782 | string that is used for mounting (in which case the kernel |
798d3a52 ZJS |
783 | default for access mode and owner will be chosen, unless |
784 | otherwise specified). This option is particularly useful for | |
785 | mounting directories such as <filename>/var</filename> as | |
786 | tmpfs, to allow state-less systems, in particular when | |
ffcd3e89 | 787 | combined with <option>--read-only</option>. |
b938cb90 | 788 | Backslash escapes are interpreted in the path, so |
ffcd3e89 RM |
789 | <literal>\:</literal> may be used to embed colons in the path. |
790 | </para></listitem> | |
798d3a52 ZJS |
791 | </varlistentry> |
792 | ||
5a8af538 LP |
793 | <varlistentry> |
794 | <term><option>--overlay=</option></term> | |
795 | <term><option>--overlay-ro=</option></term> | |
796 | ||
797 | <listitem><para>Combine multiple directory trees into one | |
798 | overlay file system and mount it into the container. Takes a | |
799 | list of colon-separated paths to the directory trees to | |
800 | combine and the destination mount point.</para> | |
801 | ||
2eadf91c RM |
802 | <para>Backslash escapes are interpreted in the paths, so |
803 | <literal>\:</literal> may be used to embed colons in the paths. | |
804 | </para> | |
805 | ||
5a8af538 LP |
806 | <para>If three or more paths are specified, then the last |
807 | specified path is the destination mount point in the | |
808 | container, all paths specified before refer to directory trees | |
809 | on the host and are combined in the specified order into one | |
810 | overlay file system. The left-most path is hence the lowest | |
811 | directory tree, the second-to-last path the highest directory | |
812 | tree in the stacking order. If <option>--overlay-ro=</option> | |
b938cb90 | 813 | is used instead of <option>--overlay=</option>, a read-only |
5a8af538 | 814 | overlay file system is created. If a writable overlay file |
b938cb90 | 815 | system is created, all changes made to it are written to the |
5a8af538 LP |
816 | highest directory tree in the stacking order, i.e. the |
817 | second-to-last specified.</para> | |
818 | ||
819 | <para>If only two paths are specified, then the second | |
820 | specified path is used both as the top-level directory tree in | |
821 | the stacking order as seen from the host, as well as the mount | |
822 | point for the overlay file system in the container. At least | |
823 | two paths have to be specified.</para> | |
824 | ||
825 | <para>For details about overlay file systems, see <ulink | |
826 | url="https://www.kernel.org/doc/Documentation/filesystems/overlayfs.txt">overlayfs.txt</ulink>. Note | |
827 | that the semantics of overlay file systems are substantially | |
828 | different from normal file systems, in particular regarding | |
829 | reported device and inode information. Device and inode | |
830 | information may change for a file while it is being written | |
831 | to, and processes might see out-of-date versions of files at | |
832 | times. Note that this switch automatically derives the | |
833 | <literal>workdir=</literal> mount option for the overlay file | |
834 | system from the top-level directory tree, making it a sibling | |
835 | of it. It is hence essential that the top-level directory tree | |
836 | is not a mount point itself (since the working directory must | |
837 | be on the same file system as the top-most directory | |
838 | tree). Also note that the <literal>lowerdir=</literal> mount | |
839 | option receives the paths to stack in the opposite order of | |
840 | this switch.</para></listitem> | |
841 | </varlistentry> | |
842 | ||
798d3a52 | 843 | <varlistentry> |
a5f1cb3b ZJS |
844 | <term><option>-E <replaceable>NAME</replaceable>=<replaceable>VALUE</replaceable></option></term> |
845 | <term><option>--setenv=<replaceable>NAME</replaceable>=<replaceable>VALUE</replaceable></option></term> | |
798d3a52 ZJS |
846 | |
847 | <listitem><para>Specifies an environment variable assignment | |
848 | to pass to the init process in the container, in the format | |
849 | <literal>NAME=VALUE</literal>. This may be used to override | |
850 | the default variables or to set additional variables. This | |
851 | parameter may be used more than once.</para></listitem> | |
852 | </varlistentry> | |
853 | ||
798d3a52 ZJS |
854 | <varlistentry> |
855 | <term><option>--register=</option></term> | |
856 | ||
857 | <listitem><para>Controls whether the container is registered | |
858 | with | |
859 | <citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>8</manvolnum></citerefentry>. | |
a8eaaee7 | 860 | Takes a boolean argument, which defaults to <literal>yes</literal>. |
798d3a52 ZJS |
861 | This option should be enabled when the container runs a full |
862 | Operating System (more specifically: an init system), and is | |
863 | useful to ensure that the container is accessible via | |
864 | <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
865 | and shown by tools such as | |
866 | <citerefentry project='man-pages'><refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum></citerefentry>. | |
867 | If the container does not run an init system, it is | |
a6b5216c | 868 | recommended to set this option to <literal>no</literal>.</para></listitem> |
798d3a52 ZJS |
869 | </varlistentry> |
870 | ||
871 | <varlistentry> | |
872 | <term><option>--keep-unit</option></term> | |
873 | ||
874 | <listitem><para>Instead of creating a transient scope unit to | |
875 | run the container in, simply register the service or scope | |
876 | unit <command>systemd-nspawn</command> has been invoked in | |
877 | with | |
878 | <citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>8</manvolnum></citerefentry>. | |
879 | This has no effect if <option>--register=no</option> is used. | |
880 | This switch should be used if | |
881 | <command>systemd-nspawn</command> is invoked from within a | |
882 | service unit, and the service unit's sole purpose is to run a | |
883 | single <command>systemd-nspawn</command> container. This | |
884 | option is not available if run from a user | |
885 | session.</para></listitem> | |
886 | </varlistentry> | |
887 | ||
888 | <varlistentry> | |
889 | <term><option>--personality=</option></term> | |
890 | ||
891 | <listitem><para>Control the architecture ("personality") | |
892 | reported by | |
3ba3a79d | 893 | <citerefentry project='man-pages'><refentrytitle>uname</refentrytitle><manvolnum>2</manvolnum></citerefentry> |
798d3a52 ZJS |
894 | in the container. Currently, only <literal>x86</literal> and |
895 | <literal>x86-64</literal> are supported. This is useful when | |
896 | running a 32-bit container on a 64-bit host. If this setting | |
897 | is not used, the personality reported in the container is the | |
898 | same as the one reported on the host.</para></listitem> | |
899 | </varlistentry> | |
900 | ||
901 | <varlistentry> | |
902 | <term><option>-q</option></term> | |
903 | <term><option>--quiet</option></term> | |
904 | ||
905 | <listitem><para>Turns off any status output by the tool | |
906 | itself. When this switch is used, the only output from nspawn | |
907 | will be the console output of the container OS | |
908 | itself.</para></listitem> | |
909 | </varlistentry> | |
910 | ||
911 | <varlistentry> | |
f757855e LP |
912 | <term><option>--volatile</option></term> |
913 | <term><option>--volatile=</option><replaceable>MODE</replaceable></term> | |
798d3a52 ZJS |
914 | |
915 | <listitem><para>Boots the container in volatile mode. When no | |
916 | mode parameter is passed or when mode is specified as | |
b938cb90 | 917 | <option>yes</option>, full volatile mode is enabled. This |
a8eaaee7 | 918 | means the root directory is mounted as a mostly unpopulated |
798d3a52 | 919 | <literal>tmpfs</literal> instance, and |
cd72d204 JE |
920 | <filename>/usr</filename> from the OS tree is mounted into it |
921 | in read-only mode (the system thus starts up with read-only OS | |
5164c3b4 ZJS |
922 | image, but pristine state and configuration, any changes |
923 | are lost on shutdown). When the mode parameter | |
b938cb90 | 924 | is specified as <option>state</option>, the OS tree is |
798d3a52 | 925 | mounted read-only, but <filename>/var</filename> is mounted as |
a8eaaee7 | 926 | a <literal>tmpfs</literal> instance into it (the system thus |
798d3a52 | 927 | starts up with read-only OS resources and configuration, but |
a8eaaee7 | 928 | pristine state, and any changes to the latter are lost on |
798d3a52 | 929 | shutdown). When the mode parameter is specified as |
b938cb90 | 930 | <option>no</option> (the default), the whole OS tree is made |
798d3a52 ZJS |
931 | available writable.</para> |
932 | ||
f757855e LP |
933 | <para>Note that setting this to <option>yes</option> or |
934 | <option>state</option> will only work correctly with | |
798d3a52 ZJS |
935 | operating systems in the container that can boot up with only |
936 | <filename>/usr</filename> mounted, and are able to populate | |
937 | <filename>/var</filename> automatically, as | |
938 | needed.</para></listitem> | |
939 | </varlistentry> | |
940 | ||
f757855e LP |
941 | <varlistentry> |
942 | <term><option>--settings=</option><replaceable>MODE</replaceable></term> | |
943 | ||
944 | <listitem><para>Controls whether | |
945 | <command>systemd-nspawn</command> shall search for and use | |
946 | additional per-container settings from | |
947 | <filename>.nspawn</filename> files. Takes a boolean or the | |
948 | special values <option>override</option> or | |
949 | <option>trusted</option>.</para> | |
950 | ||
b938cb90 | 951 | <para>If enabled (the default), a settings file named after the |
f757855e LP |
952 | machine (as specified with the <option>--machine=</option> |
953 | setting, or derived from the directory or image file name) | |
954 | with the suffix <filename>.nspawn</filename> is searched in | |
955 | <filename>/etc/systemd/nspawn/</filename> and | |
956 | <filename>/run/systemd/nspawn/</filename>. If it is found | |
957 | there, its settings are read and used. If it is not found | |
b938cb90 | 958 | there, it is subsequently searched in the same directory as the |
f757855e | 959 | image file or in the immediate parent of the root directory of |
b938cb90 | 960 | the container. In this case, if the file is found, its settings |
f757855e | 961 | will be also read and used, but potentially unsafe settings |
b938cb90 | 962 | are ignored. Note that in both these cases, settings on the |
4f76ef04 | 963 | command line take precedence over the corresponding settings |
f757855e LP |
964 | from loaded <filename>.nspawn</filename> files, if both are |
965 | specified. Unsafe settings are considered all settings that | |
966 | elevate the container's privileges or grant access to | |
967 | additional resources such as files or directories of the | |
968 | host. For details about the format and contents of | |
b938cb90 | 969 | <filename>.nspawn</filename> files, consult |
f757855e LP |
970 | <citerefentry><refentrytitle>systemd.nspawn</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> |
971 | ||
b938cb90 JE |
972 | <para>If this option is set to <option>override</option>, the |
973 | file is searched, read and used the same way, however, the order of | |
f757855e LP |
974 | precedence is reversed: settings read from the |
975 | <filename>.nspawn</filename> file will take precedence over | |
976 | the corresponding command line options, if both are | |
977 | specified.</para> | |
978 | ||
b938cb90 | 979 | <para>If this option is set to <option>trusted</option>, the |
f757855e | 980 | file is searched, read and used the same way, but regardless |
a8eaaee7 | 981 | of being found in <filename>/etc/systemd/nspawn/</filename>, |
f757855e LP |
982 | <filename>/run/systemd/nspawn/</filename> or next to the image |
983 | file or container root directory, all settings will take | |
b938cb90 | 984 | effect, however, command line arguments still take precedence |
f757855e LP |
985 | over corresponding settings.</para> |
986 | ||
b938cb90 | 987 | <para>If disabled, no <filename>.nspawn</filename> file is read |
f757855e LP |
988 | and no settings except the ones on the command line are in |
989 | effect.</para></listitem> | |
990 | </varlistentry> | |
991 | ||
9c1e04d0 | 992 | <varlistentry> |
b09c0bba | 993 | <term><option>--notify-ready=</option></term> |
9c1e04d0 AP |
994 | |
995 | <listitem><para>Configures support for notifications from the container's init process. | |
b09c0bba | 996 | <option>--notify-ready=</option> takes a boolean (<option>no</option> and <option>yes</option>). |
9c1e04d0 AP |
997 | With option <option>no</option> systemd-nspawn notifies systemd |
998 | with a <literal>READY=1</literal> message when the init process is created. | |
999 | With option <option>yes</option> systemd-nspawn waits for the | |
1000 | <literal>READY=1</literal> message from the init process in the container | |
1001 | before sending its own to systemd. For more details about notifications | |
1002 | see <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>).</para></listitem> | |
1003 | </varlistentry> | |
1004 | ||
798d3a52 ZJS |
1005 | <xi:include href="standard-options.xml" xpointer="help" /> |
1006 | <xi:include href="standard-options.xml" xpointer="version" /> | |
1007 | </variablelist> | |
1008 | ||
1009 | </refsect1> | |
1010 | ||
1011 | <refsect1> | |
1012 | <title>Examples</title> | |
1013 | ||
1014 | <example> | |
1015 | <title>Download a Fedora image and start a shell in it</title> | |
1016 | ||
96ee6ce3 SS |
1017 | <programlisting># machinectl pull-raw --verify=no http://ftp.halifax.rwth-aachen.de/fedora/linux/releases/24/CloudImages/x86_64/images/Fedora-Cloud-Base-24-1.2.x86_64.raw.xz |
1018 | # systemd-nspawn -M Fedora-Cloud-Base-24-1.2.x86_64.raw</programlisting> | |
e0ea94c1 | 1019 | |
798d3a52 ZJS |
1020 | <para>This downloads an image using |
1021 | <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
1022 | and opens a shell in it.</para> | |
1023 | </example> | |
e0ea94c1 | 1024 | |
798d3a52 ZJS |
1025 | <example> |
1026 | <title>Build and boot a minimal Fedora distribution in a container</title> | |
8f7a3c14 | 1027 | |
09c76ef6 | 1028 | <programlisting># dnf -y --releasever=23 --installroot=/srv/mycontainer --disablerepo='*' --enablerepo=fedora --enablerepo=updates install systemd passwd dnf fedora-release vim-minimal |
2b3987a8 | 1029 | # systemd-nspawn -bD /srv/mycontainer</programlisting> |
8f7a3c14 | 1030 | |
798d3a52 ZJS |
1031 | <para>This installs a minimal Fedora distribution into the |
1032 | directory <filename noindex='true'>/srv/mycontainer/</filename> | |
1033 | and then boots an OS in a namespace container in it.</para> | |
1034 | </example> | |
8f7a3c14 | 1035 | |
798d3a52 ZJS |
1036 | <example> |
1037 | <title>Spawn a shell in a container of a minimal Debian unstable distribution</title> | |
8f7a3c14 | 1038 | |
798d3a52 | 1039 | <programlisting># debootstrap --arch=amd64 unstable ~/debian-tree/ |
25f5971b | 1040 | # systemd-nspawn -D ~/debian-tree/</programlisting> |
8f7a3c14 | 1041 | |
798d3a52 ZJS |
1042 | <para>This installs a minimal Debian unstable distribution into |
1043 | the directory <filename>~/debian-tree/</filename> and then | |
1044 | spawns a shell in a namespace container in it.</para> | |
1045 | </example> | |
8f7a3c14 | 1046 | |
798d3a52 ZJS |
1047 | <example> |
1048 | <title>Boot a minimal Arch Linux distribution in a container</title> | |
68562936 | 1049 | |
798d3a52 | 1050 | <programlisting># pacstrap -c -d ~/arch-tree/ base |
68562936 WG |
1051 | # systemd-nspawn -bD ~/arch-tree/</programlisting> |
1052 | ||
ff9b60f3 | 1053 | <para>This installs a minimal Arch Linux distribution into the |
798d3a52 ZJS |
1054 | directory <filename>~/arch-tree/</filename> and then boots an OS |
1055 | in a namespace container in it.</para> | |
1056 | </example> | |
68562936 | 1057 | |
798d3a52 ZJS |
1058 | <example> |
1059 | <title>Boot into an ephemeral <literal>btrfs</literal> snapshot of the host system</title> | |
f9f4dd51 | 1060 | |
798d3a52 | 1061 | <programlisting># systemd-nspawn -D / -xb</programlisting> |
f9f4dd51 | 1062 | |
798d3a52 ZJS |
1063 | <para>This runs a copy of the host system in a |
1064 | <literal>btrfs</literal> snapshot which is removed immediately | |
1065 | when the container exits. All file system changes made during | |
1066 | runtime will be lost on shutdown, hence.</para> | |
1067 | </example> | |
f9f4dd51 | 1068 | |
798d3a52 ZJS |
1069 | <example> |
1070 | <title>Run a container with SELinux sandbox security contexts</title> | |
a8828ed9 | 1071 | |
798d3a52 | 1072 | <programlisting># chcon system_u:object_r:svirt_sandbox_file_t:s0:c0,c1 -R /srv/container |
a8828ed9 | 1073 | # systemd-nspawn -L system_u:object_r:svirt_sandbox_file_t:s0:c0,c1 -Z system_u:system_r:svirt_lxc_net_t:s0:c0,c1 -D /srv/container /bin/sh</programlisting> |
798d3a52 ZJS |
1074 | </example> |
1075 | </refsect1> | |
1076 | ||
1077 | <refsect1> | |
1078 | <title>Exit status</title> | |
1079 | ||
1080 | <para>The exit code of the program executed in the container is | |
1081 | returned.</para> | |
1082 | </refsect1> | |
1083 | ||
1084 | <refsect1> | |
1085 | <title>See Also</title> | |
1086 | <para> | |
1087 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
f757855e | 1088 | <citerefentry><refentrytitle>systemd.nspawn</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
798d3a52 ZJS |
1089 | <citerefentry project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
1090 | <citerefentry project='mankier'><refentrytitle>dnf</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
798d3a52 ZJS |
1091 | <citerefentry project='die-net'><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
1092 | <citerefentry project='archlinux'><refentrytitle>pacman</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
1093 | <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
1094 | <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
3ba3a79d | 1095 | <citerefentry project='man-pages'><refentrytitle>btrfs</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
798d3a52 ZJS |
1096 | </para> |
1097 | </refsect1> | |
8f7a3c14 LP |
1098 | |
1099 | </refentry> |