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1 | <?xml version='1.0'?> <!--*-nxml-*--> |
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 |
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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> | |
61 | <arg choice="plain">-b</arg> | |
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 | ||
70 | <para><command>systemd-nspawn</command> may be used to run a | |
71 | command or OS in a light-weight namespace container. In many ways | |
72 | it is similar to | |
73 | <citerefentry project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
74 | but more powerful since it fully virtualizes the file system | |
75 | hierarchy, as well as the process tree, the various IPC subsystems | |
76 | and the host and domain name.</para> | |
77 | ||
78 | <para><command>systemd-nspawn</command> limits access to various | |
79 | kernel interfaces in the container to read-only, such as | |
80 | <filename>/sys</filename>, <filename>/proc/sys</filename> or | |
81 | <filename>/sys/fs/selinux</filename>. Network interfaces and the | |
82 | system clock may not be changed from within the container. Device | |
83 | nodes may not be created. The host system cannot be rebooted and | |
84 | kernel modules may not be loaded from within the container.</para> | |
85 | ||
86 | <para>Note that even though these security precautions are taken | |
7de7ee62 | 87 | <command>systemd-nspawn</command> is not suitable for fully secure |
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88 | container setups. Many of the security features may be |
89 | circumvented and are hence primarily useful to avoid accidental | |
7de7ee62 | 90 | changes to the host system from the container.</para> |
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91 | |
92 | <para>In contrast to | |
93 | <citerefentry project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry> <command>systemd-nspawn</command> | |
94 | may be used to boot full Linux-based operating systems in a | |
95 | container.</para> | |
96 | ||
97 | <para>Use a tool like | |
98 | <citerefentry project='mankier'><refentrytitle>dnf</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
99 | <citerefentry project='die-net'><refentrytitle>yum</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
100 | <citerefentry project='die-net'><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
101 | or | |
102 | <citerefentry project='archlinux'><refentrytitle>pacman</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
103 | to set up an OS directory tree suitable as file system hierarchy | |
104 | for <command>systemd-nspawn</command> containers.</para> | |
105 | ||
106 | <para>Note that <command>systemd-nspawn</command> will mount file | |
107 | systems private to the container to <filename>/dev</filename>, | |
108 | <filename>/run</filename> and similar. These will not be visible | |
109 | outside of the container, and their contents will be lost when the | |
110 | container exits.</para> | |
111 | ||
112 | <para>Note that running two <command>systemd-nspawn</command> | |
113 | containers from the same directory tree will not make processes in | |
114 | them see each other. The PID namespace separation of the two | |
115 | containers is complete and the containers will share very few | |
116 | runtime objects except for the underlying file system. Use | |
117 | <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s | |
118 | <command>login</command> command to request an additional login | |
119 | prompt in a running container.</para> | |
120 | ||
121 | <para><command>systemd-nspawn</command> implements the | |
122 | <ulink | |
123 | url="http://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container | |
124 | Interface</ulink> specification.</para> | |
125 | ||
126 | <para>As a safety check <command>systemd-nspawn</command> will | |
127 | verify the existence of <filename>/usr/lib/os-release</filename> | |
128 | or <filename>/etc/os-release</filename> in the container tree | |
129 | before starting the container (see | |
130 | <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry>). | |
131 | It might be necessary to add this file to the container tree | |
132 | manually if the OS of the container is too old to contain this | |
133 | file out-of-the-box.</para> | |
134 | </refsect1> | |
135 | ||
136 | <refsect1> | |
137 | <title>Options</title> | |
138 | ||
139 | <para>If option <option>-b</option> is specified, the arguments | |
140 | are used as arguments for the init binary. Otherwise, | |
141 | <replaceable>COMMAND</replaceable> specifies the program to launch | |
142 | in the container, and the remaining arguments are used as | |
143 | arguments for this program. If <option>-b</option> is not used and | |
ff9b60f3 | 144 | no arguments are specified, a shell is launched in the |
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145 | container.</para> |
146 | ||
147 | <para>The following options are understood:</para> | |
148 | ||
149 | <variablelist> | |
150 | <varlistentry> | |
151 | <term><option>-D</option></term> | |
152 | <term><option>--directory=</option></term> | |
153 | ||
154 | <listitem><para>Directory to use as file system root for the | |
155 | container.</para> | |
156 | ||
157 | <para>If neither <option>--directory=</option>, nor | |
158 | <option>--image=</option> is specified the directory is | |
159 | determined as <filename>/var/lib/machines/</filename> suffixed | |
160 | by the machine name as specified with | |
161 | <option>--machine=</option>. If neither | |
162 | <option>--directory=</option>, <option>--image=</option>, nor | |
163 | <option>--machine=</option> are specified, the current | |
164 | directory will be used. May not be specified together with | |
165 | <option>--image=</option>.</para></listitem> | |
166 | </varlistentry> | |
167 | ||
168 | <varlistentry> | |
169 | <term><option>--template=</option></term> | |
170 | ||
171 | <listitem><para>Directory or <literal>btrfs</literal> | |
172 | subvolume to use as template for the container's root | |
173 | directory. If this is specified and the container's root | |
174 | directory (as configured by <option>--directory=</option>) | |
175 | does not yet exist it is created as <literal>btrfs</literal> | |
176 | subvolume and populated from this template tree. Ideally, the | |
177 | specified template path refers to the root of a | |
178 | <literal>btrfs</literal> subvolume, in which case a simple | |
179 | copy-on-write snapshot is taken, and populating the root | |
180 | directory is instant. If the specified template path does not | |
181 | refer to the root of a <literal>btrfs</literal> subvolume (or | |
182 | not even to a <literal>btrfs</literal> file system at all), | |
183 | the tree is copied, which can be substantially more | |
184 | time-consuming. Note that if this option is used the | |
185 | container's root directory (in contrast to the template | |
186 | directory!) must be located on a <literal>btrfs</literal> file | |
187 | system, so that the <literal>btrfs</literal> subvolume may be | |
188 | created. May not be specified together with | |
189 | <option>--image=</option> or | |
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190 | <option>--ephemeral</option>.</para> |
191 | ||
192 | <para>Note that this switch leaves host name, machine ID and | |
193 | all other settings that could identify the instance | |
194 | unmodified.</para></listitem> | |
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195 | </varlistentry> |
196 | ||
197 | <varlistentry> | |
198 | <term><option>-x</option></term> | |
199 | <term><option>--ephemeral</option></term> | |
200 | ||
201 | <listitem><para>If specified, the container is run with a | |
202 | temporary <literal>btrfs</literal> snapshot of its root | |
203 | directory (as configured with <option>--directory=</option>), | |
204 | that is removed immediately when the container terminates. | |
205 | This option is only supported if the root file system is | |
206 | <literal>btrfs</literal>. May not be specified together with | |
207 | <option>--image=</option> or | |
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208 | <option>--template=</option>.</para> |
209 | <para>Note that this switch leaves host name, machine ID and | |
210 | all other settings that could identify the instance | |
211 | unmodified.</para></listitem> | |
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212 | </varlistentry> |
213 | ||
214 | <varlistentry> | |
215 | <term><option>-i</option></term> | |
216 | <term><option>--image=</option></term> | |
217 | ||
218 | <listitem><para>Disk image to mount the root directory for the | |
219 | container from. Takes a path to a regular file or to a block | |
220 | device node. The file or block device must contain | |
221 | either:</para> | |
222 | ||
223 | <itemizedlist> | |
224 | <listitem><para>An MBR partition table with a single | |
225 | partition of type 0x83 that is marked | |
226 | bootable.</para></listitem> | |
227 | ||
228 | <listitem><para>A GUID partition table (GPT) with a single | |
229 | partition of type | |
230 | 0fc63daf-8483-4772-8e79-3d69d8477de4.</para></listitem> | |
231 | ||
232 | <listitem><para>A GUID partition table (GPT) with a marked | |
233 | root partition which is mounted as the root directory of the | |
234 | container. Optionally, GPT images may contain a home and/or | |
235 | a server data partition which are mounted to the appropriate | |
236 | places in the container. All these partitions must be | |
237 | identified by the partition types defined by the <ulink | |
238 | url="http://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/">Discoverable | |
239 | Partitions Specification</ulink>.</para></listitem> | |
240 | </itemizedlist> | |
241 | ||
242 | <para>Any other partitions, such as foreign partitions, swap | |
243 | partitions or EFI system partitions are not mounted. May not | |
244 | be specified together with <option>--directory=</option>, | |
245 | <option>--template=</option> or | |
246 | <option>--ephemeral</option>.</para></listitem> | |
247 | </varlistentry> | |
248 | ||
249 | <varlistentry> | |
250 | <term><option>-b</option></term> | |
251 | <term><option>--boot</option></term> | |
252 | ||
253 | <listitem><para>Automatically search for an init binary and | |
254 | invoke it instead of a shell or a user supplied program. If | |
255 | this option is used, arguments specified on the command line | |
256 | are used as arguments for the init binary. This option may not | |
257 | be combined with <option>--share-system</option>. | |
258 | </para></listitem> | |
259 | </varlistentry> | |
260 | ||
261 | <varlistentry> | |
262 | <term><option>-u</option></term> | |
263 | <term><option>--user=</option></term> | |
264 | ||
265 | <listitem><para>After transitioning into the container, change | |
266 | to the specified user-defined in the container's user | |
267 | database. Like all other systemd-nspawn features, this is not | |
268 | a security feature and provides protection against accidental | |
269 | destructive operations only.</para></listitem> | |
270 | </varlistentry> | |
271 | ||
272 | <varlistentry> | |
273 | <term><option>-M</option></term> | |
274 | <term><option>--machine=</option></term> | |
275 | ||
276 | <listitem><para>Sets the machine name for this container. This | |
277 | name may be used to identify this container during its runtime | |
278 | (for example in tools like | |
279 | <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
280 | and similar), and is used to initialize the container's | |
281 | hostname (which the container can choose to override, | |
282 | however). If not specified, the last component of the root | |
283 | directory path of the container is used, possibly suffixed | |
284 | with a random identifier in case <option>--ephemeral</option> | |
285 | mode is selected. If the root directory selected is the host's | |
286 | root directory the host's hostname is used as default | |
287 | instead.</para></listitem> | |
288 | </varlistentry> | |
289 | ||
290 | <varlistentry> | |
291 | <term><option>--uuid=</option></term> | |
292 | ||
293 | <listitem><para>Set the specified UUID for the container. The | |
294 | init system will initialize | |
295 | <filename>/etc/machine-id</filename> from this if this file is | |
296 | not set yet. </para></listitem> | |
297 | </varlistentry> | |
298 | ||
299 | <varlistentry> | |
300 | <term><option>--slice=</option></term> | |
301 | ||
302 | <listitem><para>Make the container part of the specified | |
303 | slice, instead of the default | |
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304 | <filename>machine.slice</filename>. This is only applies if |
305 | the machine is run in its own scope unit, i.e. if | |
306 | <option>--keep-unit</option> is not used.</para> | |
307 | </listitem> | |
308 | </varlistentry> | |
309 | ||
310 | <varlistentry> | |
311 | <term><option>--property=</option></term> | |
312 | ||
313 | <listitem><para>Set a unit property on the scope unit to | |
314 | register for the machine. This only applies if the machine is | |
315 | run in its own scope unit, i.e. if | |
316 | <option>--keep-unit</option> is not used. Takes unit property | |
317 | assignments in the same format as <command>systemctl | |
318 | set-property</command>. This is useful to set memory limits | |
319 | and similar for machines.</para> | |
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320 | </listitem> |
321 | </varlistentry> | |
322 | ||
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323 | <varlistentry> |
324 | <term><option>--private-users=</option></term> | |
325 | ||
326 | <listitem><para>Enables user namespacing. If enabled the | |
327 | container will run with its own private set of Unix user and | |
328 | group ids (UIDs and GIDs). Takes none, one or two | |
329 | colon-separated parameters: the first parameter specifies the | |
330 | first host UID to assign to the container, the second | |
331 | parameter specifies the number of host UIDs to assign to the | |
332 | container. If the second parameter is omitted, 65536 UIDs are | |
7c918141 | 333 | assigned. If the first parameter is also omitted (and hence |
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334 | no parameter passed at all), the first UID assigned to the |
335 | container is read from the owner of the root directory of the | |
336 | container's directory tree. By default no user namespacing is | |
337 | applied.</para> | |
338 | ||
339 | <para>Note that user namespacing currently requires OS trees | |
340 | that are prepared for the UID shift that is being applied: | |
341 | UIDs and GIDs used for file ownership or in file ACL entries | |
342 | must be shifted to the container UID base that is | |
343 | used during container runtime.</para> | |
344 | ||
345 | <para>It is recommended to assign as least 65536 UIDs to each | |
346 | container, so that the usable UID range in the container | |
347 | covers 16bit. For best security do not assign overlapping UID | |
348 | ranges to multiple containers. It is hence a good idea to use | |
349 | the upper 16bit of the host 32bit UIDs as container | |
350 | identifier, while the lower 16bit encode the container UID | |
351 | used.</para> | |
352 | ||
353 | <para>When user namespaces are used the GID range assigned to | |
354 | each container is always chosen identical to the UID | |
355 | range.</para></listitem> | |
356 | </varlistentry> | |
357 | ||
358 | ||
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359 | <varlistentry> |
360 | <term><option>--private-network</option></term> | |
361 | ||
362 | <listitem><para>Disconnect networking of the container from | |
363 | the host. This makes all network interfaces unavailable in the | |
364 | container, with the exception of the loopback device and those | |
365 | specified with <option>--network-interface=</option> and | |
366 | configured with <option>--network-veth</option>. If this | |
367 | option is specified, the CAP_NET_ADMIN capability will be | |
368 | added to the set of capabilities the container retains. The | |
369 | latter may be disabled by using | |
370 | <option>--drop-capability=</option>.</para></listitem> | |
371 | </varlistentry> | |
372 | ||
373 | <varlistentry> | |
374 | <term><option>--network-interface=</option></term> | |
375 | ||
376 | <listitem><para>Assign the specified network interface to the | |
377 | container. This will remove the specified interface from the | |
378 | calling namespace and place it in the container. When the | |
379 | container terminates, it is moved back to the host namespace. | |
380 | Note that <option>--network-interface=</option> implies | |
381 | <option>--private-network</option>. This option may be used | |
382 | more than once to add multiple network interfaces to the | |
383 | container.</para></listitem> | |
384 | </varlistentry> | |
385 | ||
386 | <varlistentry> | |
387 | <term><option>--network-macvlan=</option></term> | |
388 | ||
389 | <listitem><para>Create a <literal>macvlan</literal> interface | |
390 | of the specified Ethernet network interface and add it to the | |
391 | container. A <literal>macvlan</literal> interface is a virtual | |
392 | interface that adds a second MAC address to an existing | |
393 | physical Ethernet link. The interface in the container will be | |
394 | named after the interface on the host, prefixed with | |
395 | <literal>mv-</literal>. Note that | |
396 | <option>--network-macvlan=</option> implies | |
397 | <option>--private-network</option>. This option may be used | |
398 | more than once to add multiple network interfaces to the | |
399 | container.</para></listitem> | |
400 | </varlistentry> | |
401 | ||
402 | <varlistentry> | |
403 | <term><option>--network-ipvlan=</option></term> | |
404 | ||
405 | <listitem><para>Create an <literal>ipvlan</literal> interface | |
406 | of the specified Ethernet network interface and add it to the | |
407 | container. An <literal>ipvlan</literal> interface is a virtual | |
408 | interface, similar to a <literal>macvlan</literal> interface, | |
409 | which uses the same MAC address as the underlying interface. | |
410 | The interface in the container will be named after the | |
411 | interface on the host, prefixed with <literal>iv-</literal>. | |
412 | Note that <option>--network-ipvlan=</option> implies | |
413 | <option>--private-network</option>. This option may be used | |
414 | more than once to add multiple network interfaces to the | |
415 | container.</para></listitem> | |
416 | </varlistentry> | |
417 | ||
418 | <varlistentry> | |
419 | <term><option>-n</option></term> | |
420 | <term><option>--network-veth</option></term> | |
421 | ||
422 | <listitem><para>Create a virtual Ethernet link | |
423 | (<literal>veth</literal>) between host and container. The host | |
424 | side of the Ethernet link will be available as a network | |
425 | interface named after the container's name (as specified with | |
426 | <option>--machine=</option>), prefixed with | |
427 | <literal>ve-</literal>. The container side of the Ethernet | |
428 | link will be named <literal>host0</literal>. Note that | |
429 | <option>--network-veth</option> implies | |
430 | <option>--private-network</option>.</para></listitem> | |
431 | </varlistentry> | |
432 | ||
433 | <varlistentry> | |
434 | <term><option>--network-bridge=</option></term> | |
435 | ||
436 | <listitem><para>Adds the host side of the Ethernet link | |
437 | created with <option>--network-veth</option> to the specified | |
438 | bridge. Note that <option>--network-bridge=</option> implies | |
439 | <option>--network-veth</option>. If this option is used, the | |
440 | host side of the Ethernet link will use the | |
441 | <literal>vb-</literal> prefix instead of | |
442 | <literal>ve-</literal>.</para></listitem> | |
443 | </varlistentry> | |
444 | ||
445 | <varlistentry> | |
446 | <term><option>-p</option></term> | |
447 | <term><option>--port=</option></term> | |
448 | ||
449 | <listitem><para>If private networking is enabled, maps an IP | |
450 | port on the host onto an IP port on the container. Takes a | |
451 | protocol specifier (either <literal>tcp</literal> or | |
452 | <literal>udp</literal>), separated by a colon from a host port | |
453 | number in the range 1 to 65535, separated by a colon from a | |
454 | container port number in the range from 1 to 65535. The | |
455 | protocol specifier and its separating colon may be omitted, in | |
456 | which case <literal>tcp</literal> is assumed. The container | |
7c918141 | 457 | port number and its colon may be omitted, in which case the |
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458 | same port as the host port is implied. This option is only |
459 | supported if private networking is used, such as | |
460 | <option>--network-veth</option> or | |
461 | <option>--network-bridge=</option>.</para></listitem> | |
462 | </varlistentry> | |
463 | ||
464 | <varlistentry> | |
465 | <term><option>-Z</option></term> | |
466 | <term><option>--selinux-context=</option></term> | |
467 | ||
468 | <listitem><para>Sets the SELinux security context to be used | |
469 | to label processes in the container.</para> | |
470 | </listitem> | |
471 | </varlistentry> | |
472 | ||
473 | <varlistentry> | |
474 | <term><option>-L</option></term> | |
475 | <term><option>--selinux-apifs-context=</option></term> | |
476 | ||
477 | <listitem><para>Sets the SELinux security context to be used | |
478 | to label files in the virtual API file systems in the | |
479 | container.</para> | |
480 | </listitem> | |
481 | </varlistentry> | |
482 | ||
483 | <varlistentry> | |
484 | <term><option>--capability=</option></term> | |
485 | ||
486 | <listitem><para>List one or more additional capabilities to | |
487 | grant the container. Takes a comma-separated list of | |
488 | capability names, see | |
489 | <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
490 | for more information. Note that the following capabilities | |
491 | will be granted in any way: CAP_CHOWN, CAP_DAC_OVERRIDE, | |
492 | CAP_DAC_READ_SEARCH, CAP_FOWNER, CAP_FSETID, CAP_IPC_OWNER, | |
493 | CAP_KILL, CAP_LEASE, CAP_LINUX_IMMUTABLE, | |
494 | CAP_NET_BIND_SERVICE, CAP_NET_BROADCAST, CAP_NET_RAW, | |
495 | CAP_SETGID, CAP_SETFCAP, CAP_SETPCAP, CAP_SETUID, | |
496 | CAP_SYS_ADMIN, CAP_SYS_CHROOT, CAP_SYS_NICE, CAP_SYS_PTRACE, | |
497 | CAP_SYS_TTY_CONFIG, CAP_SYS_RESOURCE, CAP_SYS_BOOT, | |
498 | CAP_AUDIT_WRITE, CAP_AUDIT_CONTROL. Also CAP_NET_ADMIN is | |
499 | retained if <option>--private-network</option> is specified. | |
500 | If the special value <literal>all</literal> is passed, all | |
501 | capabilities are retained.</para></listitem> | |
502 | </varlistentry> | |
503 | ||
504 | <varlistentry> | |
505 | <term><option>--drop-capability=</option></term> | |
506 | ||
507 | <listitem><para>Specify one or more additional capabilities to | |
508 | drop for the container. This allows running the container with | |
509 | fewer capabilities than the default (see | |
510 | above).</para></listitem> | |
511 | </varlistentry> | |
512 | ||
c6c8f6e2 LP |
513 | <varlistentry> |
514 | <term><option>--kill-signal=</option></term> | |
515 | ||
516 | <listitem><para>Specify the process signal to send to the | |
517 | container's PID 1 when nspawn itself receives SIGTERM, in | |
518 | order to trigger an orderly shutdown of the | |
519 | container. Defaults to SIGRTMIN+3 if <option>--boot</option> | |
520 | is used (on systemd-compatible init systems SIGRTMIN+3 | |
521 | triggers an orderly shutdown). Takes a signal name like | |
522 | <literal>SIGHUP</literal>, <literal>SIGTERM</literal> or | |
523 | similar as argument.</para></listitem> | |
524 | </varlistentry> | |
525 | ||
798d3a52 ZJS |
526 | <varlistentry> |
527 | <term><option>--link-journal=</option></term> | |
528 | ||
529 | <listitem><para>Control whether the container's journal shall | |
530 | be made visible to the host system. If enabled, allows viewing | |
531 | the container's journal files from the host (but not vice | |
532 | versa). Takes one of <literal>no</literal>, | |
533 | <literal>host</literal>, <literal>try-host</literal>, | |
534 | <literal>guest</literal>, <literal>try-guest</literal>, | |
535 | <literal>auto</literal>. If <literal>no</literal>, the journal | |
536 | is not linked. If <literal>host</literal>, the journal files | |
537 | are stored on the host file system (beneath | |
538 | <filename>/var/log/journal/<replaceable>machine-id</replaceable></filename>) | |
539 | and the subdirectory is bind-mounted into the container at the | |
540 | same location. If <literal>guest</literal>, the journal files | |
541 | are stored on the guest file system (beneath | |
542 | <filename>/var/log/journal/<replaceable>machine-id</replaceable></filename>) | |
543 | and the subdirectory is symlinked into the host at the same | |
544 | location. <literal>try-host</literal> and | |
545 | <literal>try-guest</literal> do the same but do not fail if | |
546 | the host does not have persistent journalling enabled. If | |
547 | <literal>auto</literal> (the default), and the right | |
548 | subdirectory of <filename>/var/log/journal</filename> exists, | |
549 | it will be bind mounted into the container. If the | |
550 | subdirectory does not exist, no linking is performed. | |
551 | Effectively, booting a container once with | |
552 | <literal>guest</literal> or <literal>host</literal> will link | |
553 | the journal persistently if further on the default of | |
554 | <literal>auto</literal> is used.</para></listitem> | |
555 | </varlistentry> | |
556 | ||
557 | <varlistentry> | |
558 | <term><option>-j</option></term> | |
559 | ||
560 | <listitem><para>Equivalent to | |
561 | <option>--link-journal=try-guest</option>.</para></listitem> | |
562 | </varlistentry> | |
563 | ||
564 | <varlistentry> | |
565 | <term><option>--read-only</option></term> | |
566 | ||
567 | <listitem><para>Mount the root file system read-only for the | |
568 | container.</para></listitem> | |
569 | </varlistentry> | |
570 | ||
571 | <varlistentry> | |
572 | <term><option>--bind=</option></term> | |
573 | <term><option>--bind-ro=</option></term> | |
574 | ||
575 | <listitem><para>Bind mount a file or directory from the host | |
576 | into the container. Either takes a path argument -- in which | |
577 | case the specified path will be mounted from the host to the | |
578 | same path in the container --, or a colon-separated pair of | |
579 | paths -- in which case the first specified path is the source | |
580 | in the host, and the second path is the destination in the | |
64b282ef LP |
581 | container. This option may be specified multiple times for |
582 | creating multiple independent bind mount points. The | |
583 | <option>--bind-ro=</option> option creates read-only bind | |
584 | mounts.</para></listitem> | |
798d3a52 ZJS |
585 | </varlistentry> |
586 | ||
587 | <varlistentry> | |
588 | <term><option>--tmpfs=</option></term> | |
589 | ||
590 | <listitem><para>Mount a tmpfs file system into the container. | |
591 | Takes a single absolute path argument that specifies where to | |
592 | mount the tmpfs instance to (in which case the directory | |
593 | access mode will be chosen as 0755, owned by root/root), or | |
594 | optionally a colon-separated pair of path and mount option | |
595 | string, that is used for mounting (in which case the kernel | |
596 | default for access mode and owner will be chosen, unless | |
597 | otherwise specified). This option is particularly useful for | |
598 | mounting directories such as <filename>/var</filename> as | |
599 | tmpfs, to allow state-less systems, in particular when | |
600 | combined with <option>--read-only</option>.</para></listitem> | |
601 | </varlistentry> | |
602 | ||
5a8af538 LP |
603 | <varlistentry> |
604 | <term><option>--overlay=</option></term> | |
605 | <term><option>--overlay-ro=</option></term> | |
606 | ||
607 | <listitem><para>Combine multiple directory trees into one | |
608 | overlay file system and mount it into the container. Takes a | |
609 | list of colon-separated paths to the directory trees to | |
610 | combine and the destination mount point.</para> | |
611 | ||
612 | <para>If three or more paths are specified, then the last | |
613 | specified path is the destination mount point in the | |
614 | container, all paths specified before refer to directory trees | |
615 | on the host and are combined in the specified order into one | |
616 | overlay file system. The left-most path is hence the lowest | |
617 | directory tree, the second-to-last path the highest directory | |
618 | tree in the stacking order. If <option>--overlay-ro=</option> | |
619 | is used instead of <option>--overlay=</option> a read-only | |
620 | overlay file system is created. If a writable overlay file | |
621 | system is created all changes made to it are written to the | |
622 | highest directory tree in the stacking order, i.e. the | |
623 | second-to-last specified.</para> | |
624 | ||
625 | <para>If only two paths are specified, then the second | |
626 | specified path is used both as the top-level directory tree in | |
627 | the stacking order as seen from the host, as well as the mount | |
628 | point for the overlay file system in the container. At least | |
629 | two paths have to be specified.</para> | |
630 | ||
631 | <para>For details about overlay file systems, see <ulink | |
632 | url="https://www.kernel.org/doc/Documentation/filesystems/overlayfs.txt">overlayfs.txt</ulink>. Note | |
633 | that the semantics of overlay file systems are substantially | |
634 | different from normal file systems, in particular regarding | |
635 | reported device and inode information. Device and inode | |
636 | information may change for a file while it is being written | |
637 | to, and processes might see out-of-date versions of files at | |
638 | times. Note that this switch automatically derives the | |
639 | <literal>workdir=</literal> mount option for the overlay file | |
640 | system from the top-level directory tree, making it a sibling | |
641 | of it. It is hence essential that the top-level directory tree | |
642 | is not a mount point itself (since the working directory must | |
643 | be on the same file system as the top-most directory | |
644 | tree). Also note that the <literal>lowerdir=</literal> mount | |
645 | option receives the paths to stack in the opposite order of | |
646 | this switch.</para></listitem> | |
647 | </varlistentry> | |
648 | ||
798d3a52 ZJS |
649 | <varlistentry> |
650 | <term><option>--setenv=</option></term> | |
651 | ||
652 | <listitem><para>Specifies an environment variable assignment | |
653 | to pass to the init process in the container, in the format | |
654 | <literal>NAME=VALUE</literal>. This may be used to override | |
655 | the default variables or to set additional variables. This | |
656 | parameter may be used more than once.</para></listitem> | |
657 | </varlistentry> | |
658 | ||
659 | <varlistentry> | |
660 | <term><option>--share-system</option></term> | |
661 | ||
662 | <listitem><para>Allows the container to share certain system | |
663 | facilities with the host. More specifically, this turns off | |
664 | PID namespacing, UTS namespacing and IPC namespacing, and thus | |
665 | allows the guest to see and interact more easily with | |
666 | processes outside of the container. Note that using this | |
667 | option makes it impossible to start up a full Operating System | |
668 | in the container, as an init system cannot operate in this | |
669 | mode. It is only useful to run specific programs or | |
670 | applications this way, without involving an init system in the | |
671 | container. This option implies <option>--register=no</option>. | |
672 | This option may not be combined with | |
673 | <option>--boot</option>.</para></listitem> | |
674 | </varlistentry> | |
675 | ||
676 | <varlistentry> | |
677 | <term><option>--register=</option></term> | |
678 | ||
679 | <listitem><para>Controls whether the container is registered | |
680 | with | |
681 | <citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>8</manvolnum></citerefentry>. | |
682 | Takes a boolean argument, defaults to <literal>yes</literal>. | |
683 | This option should be enabled when the container runs a full | |
684 | Operating System (more specifically: an init system), and is | |
685 | useful to ensure that the container is accessible via | |
686 | <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
687 | and shown by tools such as | |
688 | <citerefentry project='man-pages'><refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum></citerefentry>. | |
689 | If the container does not run an init system, it is | |
690 | recommended to set this option to <literal>no</literal>. Note | |
691 | that <option>--share-system</option> implies | |
692 | <option>--register=no</option>. </para></listitem> | |
693 | </varlistentry> | |
694 | ||
695 | <varlistentry> | |
696 | <term><option>--keep-unit</option></term> | |
697 | ||
698 | <listitem><para>Instead of creating a transient scope unit to | |
699 | run the container in, simply register the service or scope | |
700 | unit <command>systemd-nspawn</command> has been invoked in | |
701 | with | |
702 | <citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>8</manvolnum></citerefentry>. | |
703 | This has no effect if <option>--register=no</option> is used. | |
704 | This switch should be used if | |
705 | <command>systemd-nspawn</command> is invoked from within a | |
706 | service unit, and the service unit's sole purpose is to run a | |
707 | single <command>systemd-nspawn</command> container. This | |
708 | option is not available if run from a user | |
709 | session.</para></listitem> | |
710 | </varlistentry> | |
711 | ||
712 | <varlistentry> | |
713 | <term><option>--personality=</option></term> | |
714 | ||
715 | <listitem><para>Control the architecture ("personality") | |
716 | reported by | |
3ba3a79d | 717 | <citerefentry project='man-pages'><refentrytitle>uname</refentrytitle><manvolnum>2</manvolnum></citerefentry> |
798d3a52 ZJS |
718 | in the container. Currently, only <literal>x86</literal> and |
719 | <literal>x86-64</literal> are supported. This is useful when | |
720 | running a 32-bit container on a 64-bit host. If this setting | |
721 | is not used, the personality reported in the container is the | |
722 | same as the one reported on the host.</para></listitem> | |
723 | </varlistentry> | |
724 | ||
725 | <varlistentry> | |
726 | <term><option>-q</option></term> | |
727 | <term><option>--quiet</option></term> | |
728 | ||
729 | <listitem><para>Turns off any status output by the tool | |
730 | itself. When this switch is used, the only output from nspawn | |
731 | will be the console output of the container OS | |
732 | itself.</para></listitem> | |
733 | </varlistentry> | |
734 | ||
735 | <varlistentry> | |
736 | <term><option>--volatile</option><replaceable>=MODE</replaceable></term> | |
737 | ||
738 | <listitem><para>Boots the container in volatile mode. When no | |
739 | mode parameter is passed or when mode is specified as | |
740 | <literal>yes</literal> full volatile mode is enabled. This | |
741 | means the root directory is mounted as mostly unpopulated | |
742 | <literal>tmpfs</literal> instance, and | |
743 | <filename>/usr</filename> from the OS tree is mounted into it, | |
744 | read-only (the system thus starts up with read-only OS | |
745 | resources, but pristine state and configuration, any changes | |
746 | to the either are lost on shutdown). When the mode parameter | |
747 | is specified as <literal>state</literal> the OS tree is | |
748 | mounted read-only, but <filename>/var</filename> is mounted as | |
749 | <literal>tmpfs</literal> instance into it (the system thus | |
750 | starts up with read-only OS resources and configuration, but | |
751 | pristine state, any changes to the latter are lost on | |
752 | shutdown). When the mode parameter is specified as | |
753 | <literal>no</literal> (the default) the whole OS tree is made | |
754 | available writable.</para> | |
755 | ||
756 | <para>Note that setting this to <literal>yes</literal> or | |
757 | <literal>state</literal> will only work correctly with | |
758 | operating systems in the container that can boot up with only | |
759 | <filename>/usr</filename> mounted, and are able to populate | |
760 | <filename>/var</filename> automatically, as | |
761 | needed.</para></listitem> | |
762 | </varlistentry> | |
763 | ||
764 | <xi:include href="standard-options.xml" xpointer="help" /> | |
765 | <xi:include href="standard-options.xml" xpointer="version" /> | |
766 | </variablelist> | |
767 | ||
768 | </refsect1> | |
769 | ||
770 | <refsect1> | |
771 | <title>Examples</title> | |
772 | ||
773 | <example> | |
774 | <title>Download a Fedora image and start a shell in it</title> | |
775 | ||
776 | <programlisting># machinectl pull-raw --verify=no http://ftp.halifax.rwth-aachen.de/fedora/linux/releases/21/Cloud/Images/x86_64/Fedora-Cloud-Base-20141203-21.x86_64.raw.xz | |
e0ea94c1 LP |
777 | # systemd-nspawn -M Fedora-Cloud-Base-20141203-21</programlisting> |
778 | ||
798d3a52 ZJS |
779 | <para>This downloads an image using |
780 | <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
781 | and opens a shell in it.</para> | |
782 | </example> | |
e0ea94c1 | 783 | |
798d3a52 ZJS |
784 | <example> |
785 | <title>Build and boot a minimal Fedora distribution in a container</title> | |
8f7a3c14 | 786 | |
798d3a52 | 787 | <programlisting># dnf -y --releasever=21 --nogpg --installroot=/srv/mycontainer --disablerepo='*' --enablerepo=fedora install systemd passwd dnf fedora-release vim-minimal |
2b3987a8 | 788 | # systemd-nspawn -bD /srv/mycontainer</programlisting> |
8f7a3c14 | 789 | |
798d3a52 ZJS |
790 | <para>This installs a minimal Fedora distribution into the |
791 | directory <filename noindex='true'>/srv/mycontainer/</filename> | |
792 | and then boots an OS in a namespace container in it.</para> | |
793 | </example> | |
8f7a3c14 | 794 | |
798d3a52 ZJS |
795 | <example> |
796 | <title>Spawn a shell in a container of a minimal Debian unstable distribution</title> | |
8f7a3c14 | 797 | |
798d3a52 | 798 | <programlisting># debootstrap --arch=amd64 unstable ~/debian-tree/ |
25f5971b | 799 | # systemd-nspawn -D ~/debian-tree/</programlisting> |
8f7a3c14 | 800 | |
798d3a52 ZJS |
801 | <para>This installs a minimal Debian unstable distribution into |
802 | the directory <filename>~/debian-tree/</filename> and then | |
803 | spawns a shell in a namespace container in it.</para> | |
804 | </example> | |
8f7a3c14 | 805 | |
798d3a52 ZJS |
806 | <example> |
807 | <title>Boot a minimal Arch Linux distribution in a container</title> | |
68562936 | 808 | |
798d3a52 | 809 | <programlisting># pacstrap -c -d ~/arch-tree/ base |
68562936 WG |
810 | # systemd-nspawn -bD ~/arch-tree/</programlisting> |
811 | ||
ff9b60f3 | 812 | <para>This installs a minimal Arch Linux distribution into the |
798d3a52 ZJS |
813 | directory <filename>~/arch-tree/</filename> and then boots an OS |
814 | in a namespace container in it.</para> | |
815 | </example> | |
68562936 | 816 | |
798d3a52 ZJS |
817 | <example> |
818 | <title>Boot into an ephemeral <literal>btrfs</literal> snapshot of the host system</title> | |
f9f4dd51 | 819 | |
798d3a52 | 820 | <programlisting># systemd-nspawn -D / -xb</programlisting> |
f9f4dd51 | 821 | |
798d3a52 ZJS |
822 | <para>This runs a copy of the host system in a |
823 | <literal>btrfs</literal> snapshot which is removed immediately | |
824 | when the container exits. All file system changes made during | |
825 | runtime will be lost on shutdown, hence.</para> | |
826 | </example> | |
f9f4dd51 | 827 | |
798d3a52 ZJS |
828 | <example> |
829 | <title>Run a container with SELinux sandbox security contexts</title> | |
a8828ed9 | 830 | |
798d3a52 | 831 | <programlisting># chcon system_u:object_r:svirt_sandbox_file_t:s0:c0,c1 -R /srv/container |
a8828ed9 | 832 | # 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 |
833 | </example> |
834 | </refsect1> | |
835 | ||
836 | <refsect1> | |
837 | <title>Exit status</title> | |
838 | ||
839 | <para>The exit code of the program executed in the container is | |
840 | returned.</para> | |
841 | </refsect1> | |
842 | ||
843 | <refsect1> | |
844 | <title>See Also</title> | |
845 | <para> | |
846 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
847 | <citerefentry project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
848 | <citerefentry project='mankier'><refentrytitle>dnf</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
849 | <citerefentry project='die-net'><refentrytitle>yum</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
850 | <citerefentry project='die-net'><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
851 | <citerefentry project='archlinux'><refentrytitle>pacman</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
852 | <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
853 | <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
3ba3a79d | 854 | <citerefentry project='man-pages'><refentrytitle>btrfs</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
798d3a52 ZJS |
855 | </para> |
856 | </refsect1> | |
8f7a3c14 LP |
857 | |
858 | </refentry> |