2 <!DOCTYPE refentry PUBLIC
"-//OASIS//DTD DocBook XML V4.5//EN"
3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
4 <!ENTITY fedora_latest_version
"32">
5 <!ENTITY fedora_cloud_release
"1.6">
7 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
9 <refentry id=
"systemd-nspawn"
10 xmlns:
xi=
"http://www.w3.org/2001/XInclude">
13 <title>systemd-nspawn
</title>
14 <productname>systemd
</productname>
18 <refentrytitle>systemd-nspawn
</refentrytitle>
19 <manvolnum>1</manvolnum>
23 <refname>systemd-nspawn
</refname>
24 <refpurpose>Spawn a command or OS in a light-weight container
</refpurpose>
29 <command>systemd-nspawn
</command>
30 <arg choice=
"opt" rep=
"repeat">OPTIONS
</arg>
31 <arg choice=
"opt"><replaceable>COMMAND
</replaceable>
32 <arg choice=
"opt" rep=
"repeat">ARGS
</arg>
36 <command>systemd-nspawn
</command>
37 <arg choice=
"plain">--boot
</arg>
38 <arg choice=
"opt" rep=
"repeat">OPTIONS
</arg>
39 <arg choice=
"opt" rep=
"repeat">ARGS
</arg>
44 <title>Description
</title>
46 <para><command>systemd-nspawn
</command> may be used to run a command or OS in a light-weight namespace
47 container. In many ways it is similar to
<citerefentry
48 project='man-pages'
><refentrytitle>chroot
</refentrytitle><manvolnum>1</manvolnum></citerefentry>, but more powerful
49 since it fully virtualizes the file system hierarchy, as well as the process tree, the various IPC subsystems and
50 the host and domain name.
</para>
52 <para><command>systemd-nspawn
</command> may be invoked on any directory tree containing an operating system tree,
53 using the
<option>--directory=
</option> command line option. By using the
<option>--machine=
</option> option an OS
54 tree is automatically searched for in a couple of locations, most importantly in
55 <filename>/var/lib/machines
</filename>, the suggested directory to place OS container images installed on the
58 <para>In contrast to
<citerefentry
59 project='man-pages'
><refentrytitle>chroot
</refentrytitle><manvolnum>1</manvolnum></citerefentry> <command>systemd-nspawn
</command>
60 may be used to boot full Linux-based operating systems in a container.
</para>
62 <para><command>systemd-nspawn
</command> limits access to various kernel interfaces in the container to read-only,
63 such as
<filename>/sys
</filename>,
<filename>/proc/sys
</filename> or
<filename>/sys/fs/selinux
</filename>. The
64 host's network interfaces and the system clock may not be changed from within the container. Device nodes may not
65 be created. The host system cannot be rebooted and kernel modules may not be loaded from within the
68 <para>Use a tool like
<citerefentry
69 project='mankier'
><refentrytitle>dnf
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry
70 project='die-net'
><refentrytitle>debootstrap
</refentrytitle><manvolnum>8</manvolnum></citerefentry>, or
71 <citerefentry project='archlinux'
><refentrytitle>pacman
</refentrytitle><manvolnum>8</manvolnum></citerefentry> to
72 set up an OS directory tree suitable as file system hierarchy for
<command>systemd-nspawn
</command> containers. See
73 the Examples section below for details on suitable invocation of these commands.
</para>
75 <para>As a safety check
<command>systemd-nspawn
</command> will verify the existence of
76 <filename>/usr/lib/os-release
</filename> or
<filename>/etc/os-release
</filename> in the container tree before
77 starting the container (see
78 <citerefentry><refentrytitle>os-release
</refentrytitle><manvolnum>5</manvolnum></citerefentry>). It might be
79 necessary to add this file to the container tree manually if the OS of the container is too old to contain this
80 file out-of-the-box.
</para>
82 <para><command>systemd-nspawn
</command> may be invoked directly from the interactive command line or run as system
83 service in the background. In this mode each container instance runs as its own service instance; a default
84 template unit file
<filename>systemd-nspawn@.service
</filename> is provided to make this easy, taking the container
85 name as instance identifier. Note that different default options apply when
<command>systemd-nspawn
</command> is
86 invoked by the template unit file than interactively on the command line. Most importantly the template unit file
87 makes use of the
<option>--boot
</option> which is not the default in case
<command>systemd-nspawn
</command> is
88 invoked from the interactive command line. Further differences with the defaults are documented along with the
89 various supported options below.
</para>
91 <para>The
<citerefentry><refentrytitle>machinectl
</refentrytitle><manvolnum>1</manvolnum></citerefentry> tool may
92 be used to execute a number of operations on containers. In particular it provides easy-to-use commands to run
93 containers as system services using the
<filename>systemd-nspawn@.service
</filename> template unit
96 <para>Along with each container a settings file with the
<filename>.nspawn
</filename> suffix may exist, containing
97 additional settings to apply when running the container. See
98 <citerefentry><refentrytitle>systemd.nspawn
</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
99 details. Settings files override the default options used by the
<filename>systemd-nspawn@.service
</filename>
100 template unit file, making it usually unnecessary to alter this template file directly.
</para>
102 <para>Note that
<command>systemd-nspawn
</command> will mount file systems private to the container to
103 <filename>/dev
</filename>,
<filename>/run
</filename> and similar. These will not be visible outside of the
104 container, and their contents will be lost when the container exits.
</para>
106 <para>Note that running two
<command>systemd-nspawn
</command> containers from the same directory tree will not make
107 processes in them see each other. The PID namespace separation of the two containers is complete and the containers
108 will share very few runtime objects except for the underlying file system. Use
109 <citerefentry><refentrytitle>machinectl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
110 <command>login
</command> or
<command>shell
</command> commands to request an additional login session in a running
113 <para><command>systemd-nspawn
</command> implements the
<ulink
114 url=
"https://systemd.io/CONTAINER_INTERFACE">Container Interface
</ulink> specification.
</para>
116 <para>While running, containers invoked with
<command>systemd-nspawn
</command> are registered with the
117 <citerefentry><refentrytitle>systemd-machined
</refentrytitle><manvolnum>8</manvolnum></citerefentry> service that
118 keeps track of running containers, and provides programming interfaces to interact with them.
</para>
122 <title>Options
</title>
124 <para>If option
<option>-b
</option> is specified, the arguments
125 are used as arguments for the init program. Otherwise,
126 <replaceable>COMMAND
</replaceable> specifies the program to launch
127 in the container, and the remaining arguments are used as
128 arguments for this program. If
<option>--boot
</option> is not used and
129 no arguments are specified, a shell is launched in the
132 <para>The following options are understood:
</para>
137 <term><option>-q
</option></term>
138 <term><option>--quiet
</option></term>
140 <listitem><para>Turns off any status output by the tool
141 itself. When this switch is used, the only output from nspawn
142 will be the console output of the container OS
143 itself.
</para></listitem>
147 <term><option>--settings=
</option><replaceable>MODE
</replaceable></term>
149 <listitem><para>Controls whether
150 <command>systemd-nspawn
</command> shall search for and use
151 additional per-container settings from
152 <filename>.nspawn
</filename> files. Takes a boolean or the
153 special values
<option>override
</option> or
154 <option>trusted
</option>.
</para>
156 <para>If enabled (the default), a settings file named after the
157 machine (as specified with the
<option>--machine=
</option>
158 setting, or derived from the directory or image file name)
159 with the suffix
<filename>.nspawn
</filename> is searched in
160 <filename>/etc/systemd/nspawn/
</filename> and
161 <filename>/run/systemd/nspawn/
</filename>. If it is found
162 there, its settings are read and used. If it is not found
163 there, it is subsequently searched in the same directory as the
164 image file or in the immediate parent of the root directory of
165 the container. In this case, if the file is found, its settings
166 will be also read and used, but potentially unsafe settings
167 are ignored. Note that in both these cases, settings on the
168 command line take precedence over the corresponding settings
169 from loaded
<filename>.nspawn
</filename> files, if both are
170 specified. Unsafe settings are considered all settings that
171 elevate the container's privileges or grant access to
172 additional resources such as files or directories of the
173 host. For details about the format and contents of
174 <filename>.nspawn
</filename> files, consult
175 <citerefentry><refentrytitle>systemd.nspawn
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
177 <para>If this option is set to
<option>override
</option>, the
178 file is searched, read and used the same way, however, the order of
179 precedence is reversed: settings read from the
180 <filename>.nspawn
</filename> file will take precedence over
181 the corresponding command line options, if both are
184 <para>If this option is set to
<option>trusted
</option>, the
185 file is searched, read and used the same way, but regardless
186 of being found in
<filename>/etc/systemd/nspawn/
</filename>,
187 <filename>/run/systemd/nspawn/
</filename> or next to the image
188 file or container root directory, all settings will take
189 effect, however, command line arguments still take precedence
190 over corresponding settings.
</para>
192 <para>If disabled, no
<filename>.nspawn
</filename> file is read
193 and no settings except the ones on the command line are in
194 effect.
</para></listitem>
200 <title>Image Options
</title>
205 <term><option>-D
</option></term>
206 <term><option>--directory=
</option></term>
208 <listitem><para>Directory to use as file system root for the
211 <para>If neither
<option>--directory=
</option>, nor
212 <option>--image=
</option> is specified the directory is
213 determined by searching for a directory named the same as the
214 machine name specified with
<option>--machine=
</option>. See
215 <citerefentry><refentrytitle>machinectl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
216 section
"Files and Directories" for the precise search path.
</para>
218 <para>If neither
<option>--directory=
</option>,
219 <option>--image=
</option>, nor
<option>--machine=
</option>
220 are specified, the current directory will
221 be used. May not be specified together with
222 <option>--image=
</option>.
</para></listitem>
226 <term><option>--template=
</option></term>
228 <listitem><para>Directory or
<literal>btrfs
</literal> subvolume to use as template for the
229 container's root directory. If this is specified and the container's root directory (as configured by
230 <option>--directory=
</option>) does not yet exist it is created as
<literal>btrfs
</literal> snapshot
231 (if supported) or plain directory (otherwise) and populated from this template tree. Ideally, the
232 specified template path refers to the root of a
<literal>btrfs
</literal> subvolume, in which case a
233 simple copy-on-write snapshot is taken, and populating the root directory is instant. If the
234 specified template path does not refer to the root of a
<literal>btrfs
</literal> subvolume (or not
235 even to a
<literal>btrfs
</literal> file system at all), the tree is copied (though possibly in a
236 'reflink' copy-on-write scheme — if the file system supports that), which can be substantially more
237 time-consuming. Note that the snapshot taken is of the specified directory or subvolume, including
238 all subdirectories and subvolumes below it, but excluding any sub-mounts. May not be specified
239 together with
<option>--image=
</option> or
<option>--ephemeral
</option>.
</para>
241 <para>Note that this switch leaves hostname, machine ID and
242 all other settings that could identify the instance
243 unmodified.
</para></listitem>
247 <term><option>-x
</option></term>
248 <term><option>--ephemeral
</option></term>
250 <listitem><para>If specified, the container is run with a temporary snapshot of its file system that is removed
251 immediately when the container terminates. May not be specified together with
252 <option>--template=
</option>.
</para>
253 <para>Note that this switch leaves hostname, machine ID and all other settings that could identify
254 the instance unmodified. Please note that — as with
<option>--template=
</option> — taking the
255 temporary snapshot is more efficient on file systems that support subvolume snapshots or 'reflinks'
256 natively (
<literal>btrfs
</literal> or new
<literal>xfs
</literal>) than on more traditional file
257 systems that do not (
<literal>ext4
</literal>). Note that the snapshot taken is of the specified
258 directory or subvolume, including all subdirectories and subvolumes below it, but excluding any
261 <para>With this option no modifications of the container image are retained. Use
262 <option>--volatile=
</option> (described below) for other mechanisms to restrict persistency of
263 container images during runtime.
</para>
268 <term><option>-i
</option></term>
269 <term><option>--image=
</option></term>
271 <listitem><para>Disk image to mount the root directory for the
272 container from. Takes a path to a regular file or to a block
273 device node. The file or block device must contain
277 <listitem><para>An MBR partition table with a single
278 partition of type
0x83 that is marked
279 bootable.
</para></listitem>
281 <listitem><para>A GUID partition table (GPT) with a single
283 0fc63daf-
8483-
4772-
8e79-
3d69d8477de4.
</para></listitem>
285 <listitem><para>A GUID partition table (GPT) with a marked
286 root partition which is mounted as the root directory of the
287 container. Optionally, GPT images may contain a home and/or
288 a server data partition which are mounted to the appropriate
289 places in the container. All these partitions must be
290 identified by the partition types defined by the
<ulink
291 url=
"https://systemd.io/DISCOVERABLE_PARTITIONS">Discoverable
292 Partitions Specification
</ulink>.
</para></listitem>
294 <listitem><para>No partition table, and a single file system spanning the whole image.
</para></listitem>
297 <para>On GPT images, if an EFI System Partition (ESP) is discovered, it is automatically mounted to
298 <filename>/efi
</filename> (or
<filename>/boot
</filename> as fallback) in case a directory by this name exists
301 <para>Partitions encrypted with LUKS are automatically decrypted. Also, on GPT images dm-verity data integrity
302 hash partitions are set up if the root hash for them is specified using the
<option>--root-hash=
</option>
305 <para>Single file system images (i.e. file systems without a surrounding partition table) can be opened using
306 dm-verity if the integrity data is passed using the
<option>--root-hash=
</option> and
307 <option>--verity-data=
</option> options.
</para>
309 <para>Any other partitions, such as foreign partitions or swap partitions are not mounted. May not be specified
310 together with
<option>--directory=
</option>,
<option>--template=
</option>.
</para></listitem>
314 <term><option>--oci-bundle=
</option></term>
316 <listitem><para>Takes the path to an OCI runtime bundle to invoke, as specified in the
<ulink
317 url=
"https://github.com/opencontainers/runtime-spec/blob/master/spec.md">OCI Runtime Specification
</ulink>. In
318 this case no
<filename>.nspawn
</filename> file is loaded, and the root directory and various settings are read
319 from the OCI runtime JSON data (but data passed on the command line takes precedence).
</para></listitem>
323 <term><option>--read-only
</option></term>
325 <listitem><para>Mount the container's root file system (and any other file systems container in the container
326 image) read-only. This has no effect on additional mounts made with
<option>--bind=
</option>,
327 <option>--tmpfs=
</option> and similar options. This mode is implied if the container image file or directory is
328 marked read-only itself. It is also implied if
<option>--volatile=
</option> is used. In this case the container
329 image on disk is strictly read-only, while changes are permitted but kept non-persistently in memory only. For
330 further details, see below.
</para></listitem>
334 <term><option>--volatile
</option></term>
335 <term><option>--volatile=
</option><replaceable>MODE
</replaceable></term>
337 <listitem><para>Boots the container in volatile mode. When no mode parameter is passed or when mode is
338 specified as
<option>yes
</option>, full volatile mode is enabled. This means the root directory is mounted as a
339 mostly unpopulated
<literal>tmpfs
</literal> instance, and
<filename>/usr/
</filename> from the OS tree is
340 mounted into it in read-only mode (the system thus starts up with read-only OS image, but pristine state and
341 configuration, any changes are lost on shutdown). When the mode parameter is specified as
342 <option>state
</option>, the OS tree is mounted read-only, but
<filename>/var/
</filename> is mounted as a
343 writable
<literal>tmpfs
</literal> instance into it (the system thus starts up with read-only OS resources and
344 configuration, but pristine state, and any changes to the latter are lost on shutdown). When the mode parameter
345 is specified as
<option>overlay
</option> the read-only root file system is combined with a writable
346 <filename>tmpfs
</filename> instance through
<literal>overlayfs
</literal>, so that it appears at it normally
347 would, but any changes are applied to the temporary file system only and lost when the container is
348 terminated. When the mode parameter is specified as
<option>no
</option> (the default), the whole OS tree is
349 made available writable (unless
<option>--read-only
</option> is specified, see above).
</para>
351 <para>Note that if one of the volatile modes is chosen, its effect is limited to the root file system (or
352 <filename>/var/
</filename> in case of
<option>state
</option>), and any other mounts placed in the hierarchy are
353 unaffected — regardless if they are established automatically (e.g. the EFI system partition that might be
354 mounted to
<filename>/efi/
</filename> or
<filename>/boot/
</filename>) or explicitly (e.g. through an additional
355 command line option such as
<option>--bind=
</option>, see below). This means, even if
356 <option>--volatile=overlay
</option> is used changes to
<filename>/efi/
</filename> or
357 <filename>/boot/
</filename> are prohibited in case such a partition exists in the container image operated on,
358 and even if
<option>--volatile=state
</option> is used the hypothetical file
<filename>/etc/foobar
</filename> is
359 potentially writable if
<option>--bind=/etc/foobar
</option> if used to mount it from outside the read-only
360 container
<filename>/etc
</filename> directory.
</para>
362 <para>The
<option>--ephemeral
</option> option is closely related to this setting, and provides similar
363 behaviour by making a temporary, ephemeral copy of the whole OS image and executing that. For further details,
366 <para>The
<option>--tmpfs=
</option> and
<option>--overlay=
</option> options provide similar functionality, but
367 for specific sub-directories of the OS image only. For details, see below.
</para>
369 <para>This option provides similar functionality for containers as the
<literal>systemd.volatile=
</literal>
370 kernel command line switch provides for host systems. See
371 <citerefentry><refentrytitle>kernel-command-line
</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
374 <para>Note that setting this option to
<option>yes
</option> or
<option>state
</option> will only work
375 correctly with operating systems in the container that can boot up with only
376 <filename>/usr/
</filename> mounted, and are able to automatically populate
<filename>/var/
</filename>
377 (and
<filename>/etc/
</filename> in case of
<literal>--volatile=yes
</literal>). Specifically, this
378 means that operating systems that follow the historic split of
<filename>/bin/
</filename> and
379 <filename>/lib/
</filename> (and related directories) from
<filename>/usr/
</filename> (i.e. where the
380 former are not symlinks into the latter) are not supported by
<literal>--volatile=yes
</literal> as
381 container payload. The
<option>overlay
</option> option does not require any particular preparations
382 in the OS, but do note that
<literal>overlayfs
</literal> behaviour differs from regular file systems
383 in a number of ways, and hence compatibility is limited.
</para></listitem>
387 <term><option>--root-hash=
</option></term>
389 <listitem><para>Takes a data integrity (dm-verity) root hash specified in hexadecimal. This option enables data
390 integrity checks using dm-verity, if the used image contains the appropriate integrity data (see above). The
391 specified hash must match the root hash of integrity data, and is usually at least
256 bits (and hence
64
392 formatted hexadecimal characters) long (in case of SHA256 for example). If this option is not specified, but
393 the image file carries the
<literal>user.verity.roothash
</literal> extended file attribute (see
<citerefentry
394 project='man-pages'
><refentrytitle>xattr
</refentrytitle><manvolnum>7</manvolnum></citerefentry>), then the root
395 hash is read from it, also as formatted hexadecimal characters. If the extended file attribute is not found (or
396 is not supported by the underlying file system), but a file with the
<filename>.roothash
</filename> suffix is
397 found next to the image file, bearing otherwise the same name (except if the image has the
398 <filename>.raw
</filename> suffix, in which case the root hash file must not have it in its name), the root hash
399 is read from it and automatically used, also as formatted hexadecimal characters.
</para></listitem>
403 <term><option>--verity-data=
</option></term>
405 <listitem><para>Takes the path to a data integrity (dm-verity) file. This option enables data integrity checks
406 using dm-verity, if a root-hash is passed and if the used image itself does not contains the integrity data.
407 The integrity data must be matched by the root hash. If this option is not specified, but a file with the
408 <filename>.verity
</filename> suffix is found next to the image file, bearing otherwise the same name (except if
409 the image has the
<filename>.raw
</filename> suffix, in which case the verity data file must not have it in its name),
410 the verity data is read from it and automatically used.
</para></listitem>
414 <term><option>--pivot-root=
</option></term>
416 <listitem><para>Pivot the specified directory to
<filename>/
</filename> inside the container, and either unmount the
417 container's old root, or pivot it to another specified directory. Takes one of: a path argument — in which case the
418 specified path will be pivoted to
<filename>/
</filename> and the old root will be unmounted; or a colon-separated pair
419 of new root path and pivot destination for the old root. The new root path will be pivoted to
<filename>/
</filename>,
420 and the old
<filename>/
</filename> will be pivoted to the other directory. Both paths must be absolute, and are resolved
421 in the container's file system namespace.
</para>
423 <para>This is for containers which have several bootable directories in them; for example, several
424 <ulink url=
"https://ostree.readthedocs.io/en/latest/">OSTree
</ulink> deployments. It emulates the behavior of
425 the boot loader and initial RAM disk which normally select which directory to mount as the root and start the
426 container's PID
1 in.
</para></listitem>
430 </refsect2><refsect2>
431 <title>Execution Options
</title>
435 <term><option>-a
</option></term>
436 <term><option>--as-pid2
</option></term>
438 <listitem><para>Invoke the shell or specified program as process ID (PID)
2 instead of PID
1 (init). By
439 default, if neither this option nor
<option>--boot
</option> is used, the selected program is run as the process
440 with PID
1, a mode only suitable for programs that are aware of the special semantics that the process with
441 PID
1 has on UNIX. For example, it needs to reap all processes reparented to it, and should implement
442 <command>sysvinit
</command> compatible signal handling (specifically: it needs to reboot on SIGINT, reexecute
443 on SIGTERM, reload configuration on SIGHUP, and so on). With
<option>--as-pid2
</option> a minimal stub init
444 process is run as PID
1 and the selected program is executed as PID
2 (and hence does not need to implement any
445 special semantics). The stub init process will reap processes as necessary and react appropriately to
446 signals. It is recommended to use this mode to invoke arbitrary commands in containers, unless they have been
447 modified to run correctly as PID
1. Or in other words: this switch should be used for pretty much all commands,
448 except when the command refers to an init or shell implementation, as these are generally capable of running
449 correctly as PID
1. This option may not be combined with
<option>--boot
</option>.
</para>
454 <term><option>-b
</option></term>
455 <term><option>--boot
</option></term>
457 <listitem><para>Automatically search for an init program and invoke it as PID
1, instead of a shell or a user
458 supplied program. If this option is used, arguments specified on the command line are used as arguments for the
459 init program. This option may not be combined with
<option>--as-pid2
</option>.
</para>
461 <para>The following table explains the different modes of invocation and relationship to
462 <option>--as-pid2
</option> (see above):
</para>
465 <title>Invocation Mode
</title>
466 <tgroup cols='
2' align='left' colsep='
1' rowsep='
1'
>
467 <colspec colname=
"switch" />
468 <colspec colname=
"explanation" />
471 <entry>Switch
</entry>
472 <entry>Explanation
</entry>
477 <entry>Neither
<option>--as-pid2
</option> nor
<option>--boot
</option> specified
</entry>
478 <entry>The passed parameters are interpreted as the command line, which is executed as PID
1 in the container.
</entry>
482 <entry><option>--as-pid2
</option> specified
</entry>
483 <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>
487 <entry><option>--boot
</option> specified
</entry>
488 <entry>An init program is automatically searched for and run as PID
1 in the container. The passed parameters are used as invocation parameters for this process.
</entry>
495 <para>Note that
<option>--boot
</option> is the default mode of operation if the
496 <filename>systemd-nspawn@.service
</filename> template unit file is used.
</para>
501 <term><option>--chdir=
</option></term>
503 <listitem><para>Change to the specified working directory before invoking the process in the container. Expects
504 an absolute path in the container's file system namespace.
</para></listitem>
508 <term><option>-E
<replaceable>NAME
</replaceable>=
<replaceable>VALUE
</replaceable></option></term>
509 <term><option>--setenv=
<replaceable>NAME
</replaceable>=
<replaceable>VALUE
</replaceable></option></term>
511 <listitem><para>Specifies an environment variable assignment
512 to pass to the init process in the container, in the format
513 <literal>NAME=VALUE
</literal>. This may be used to override
514 the default variables or to set additional variables. This
515 parameter may be used more than once.
</para></listitem>
519 <term><option>-u
</option></term>
520 <term><option>--user=
</option></term>
522 <listitem><para>After transitioning into the container, change
523 to the specified user-defined in the container's user
524 database. Like all other systemd-nspawn features, this is not
525 a security feature and provides protection against accidental
526 destructive operations only.
</para></listitem>
530 <term><option>--kill-signal=
</option></term>
532 <listitem><para>Specify the process signal to send to the container's PID
1 when nspawn itself receives
533 <constant>SIGTERM
</constant>, in order to trigger an orderly shutdown of the container. Defaults to
534 <constant>SIGRTMIN+
3</constant> if
<option>--boot
</option> is used (on systemd-compatible init systems
535 <constant>SIGRTMIN+
3</constant> triggers an orderly shutdown). If
<option>--boot
</option> is not used and this
536 option is not specified the container's processes are terminated abruptly via
<constant>SIGKILL
</constant>. For
537 a list of valid signals, see
<citerefentry
538 project='man-pages'
><refentrytitle>signal
</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
</para></listitem>
542 <term><option>--notify-ready=
</option></term>
544 <listitem><para>Configures support for notifications from the container's init process.
545 <option>--notify-ready=
</option> takes a boolean (
<option>no
</option> and
<option>yes
</option>).
546 With option
<option>no
</option> systemd-nspawn notifies systemd
547 with a
<literal>READY=
1</literal> message when the init process is created.
548 With option
<option>yes
</option> systemd-nspawn waits for the
549 <literal>READY=
1</literal> message from the init process in the container
550 before sending its own to systemd. For more details about notifications
551 see
<citerefentry><refentrytitle>sd_notify
</refentrytitle><manvolnum>3</manvolnum></citerefentry>).
</para></listitem>
555 </refsect2><refsect2>
556 <title>System Identity Options
</title>
560 <term><option>-M
</option></term>
561 <term><option>--machine=
</option></term>
563 <listitem><para>Sets the machine name for this container. This
564 name may be used to identify this container during its runtime
565 (for example in tools like
566 <citerefentry><refentrytitle>machinectl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
567 and similar), and is used to initialize the container's
568 hostname (which the container can choose to override,
569 however). If not specified, the last component of the root
570 directory path of the container is used, possibly suffixed
571 with a random identifier in case
<option>--ephemeral
</option>
572 mode is selected. If the root directory selected is the host's
573 root directory the host's hostname is used as default
574 instead.
</para></listitem>
578 <term><option>--hostname=
</option></term>
580 <listitem><para>Controls the hostname to set within the container, if different from the machine name. Expects
581 a valid hostname as argument. If this option is used, the kernel hostname of the container will be set to this
582 value, otherwise it will be initialized to the machine name as controlled by the
<option>--machine=
</option>
583 option described above. The machine name is used for various aspect of identification of the container from the
584 outside, the kernel hostname configurable with this option is useful for the container to identify itself from
585 the inside. It is usually a good idea to keep both forms of identification synchronized, in order to avoid
586 confusion. It is hence recommended to avoid usage of this option, and use
<option>--machine=
</option>
587 exclusively. Note that regardless whether the container's hostname is initialized from the name set with
588 <option>--hostname=
</option> or the one set with
<option>--machine=
</option>, the container can later override
589 its kernel hostname freely on its own as well.
</para>
594 <term><option>--uuid=
</option></term>
596 <listitem><para>Set the specified UUID for the container. The
597 init system will initialize
598 <filename>/etc/machine-id
</filename> from this if this file is
599 not set yet. Note that this option takes effect only if
600 <filename>/etc/machine-id
</filename> in the container is
601 unpopulated.
</para></listitem>
605 </refsect2><refsect2>
606 <title>Property Options
</title>
610 <term><option>-S
</option></term>
611 <term><option>--slice=
</option></term>
613 <listitem><para>Make the container part of the specified slice, instead of the default
614 <filename>machine.slice
</filename>. This applies only if the machine is run in its own scope unit, i.e. if
615 <option>--keep-unit
</option> isn't used.
</para>
620 <term><option>--property=
</option></term>
622 <listitem><para>Set a unit property on the scope unit to register for the machine. This applies only if the
623 machine is run in its own scope unit, i.e. if
<option>--keep-unit
</option> isn't used. Takes unit property
624 assignments in the same format as
<command>systemctl set-property
</command>. This is useful to set memory
625 limits and similar for container.
</para>
630 <term><option>--register=
</option></term>
632 <listitem><para>Controls whether the container is registered with
633 <citerefentry><refentrytitle>systemd-machined
</refentrytitle><manvolnum>8</manvolnum></citerefentry>. Takes a
634 boolean argument, which defaults to
<literal>yes
</literal>. This option should be enabled when the container
635 runs a full Operating System (more specifically: a system and service manager as PID
1), and is useful to
636 ensure that the container is accessible via
637 <citerefentry><refentrytitle>machinectl
</refentrytitle><manvolnum>1</manvolnum></citerefentry> and shown by
638 tools such as
<citerefentry
639 project='man-pages'
><refentrytitle>ps
</refentrytitle><manvolnum>1</manvolnum></citerefentry>. If the container
640 does not run a service manager, it is recommended to set this option to
641 <literal>no
</literal>.
</para></listitem>
645 <term><option>--keep-unit
</option></term>
647 <listitem><para>Instead of creating a transient scope unit to run the container in, simply use the service or
648 scope unit
<command>systemd-nspawn
</command> has been invoked in. If
<option>--register=yes
</option> is set
649 this unit is registered with
650 <citerefentry><refentrytitle>systemd-machined
</refentrytitle><manvolnum>8</manvolnum></citerefentry>. This
651 switch should be used if
<command>systemd-nspawn
</command> is invoked from within a service unit, and the
652 service unit's sole purpose is to run a single
<command>systemd-nspawn
</command> container. This option is not
653 available if run from a user session.
</para>
654 <para>Note that passing
<option>--keep-unit
</option> disables the effect of
<option>--slice=
</option> and
655 <option>--property=
</option>. Use
<option>--keep-unit
</option> and
<option>--register=no
</option> in
656 combination to disable any kind of unit allocation or registration with
657 <command>systemd-machined
</command>.
</para></listitem>
661 </refsect2><refsect2>
662 <title>User Namespacing Options
</title>
666 <term><option>--private-users=
</option></term>
668 <listitem><para>Controls user namespacing. If enabled, the container will run with its own private set of UNIX
669 user and group ids (UIDs and GIDs). This involves mapping the private UIDs/GIDs used in the container (starting
670 with the container's root user
0 and up) to a range of UIDs/GIDs on the host that are not used for other
671 purposes (usually in the range beyond the host's UID/GID
65536). The parameter may be specified as follows:
</para>
674 <listitem><para>If one or two colon-separated numbers are specified, user namespacing is turned on. The first
675 parameter specifies the first host UID/GID to assign to the container, the second parameter specifies the
676 number of host UIDs/GIDs to assign to the container. If the second parameter is omitted,
65536 UIDs/GIDs are
677 assigned.
</para></listitem>
679 <listitem><para>If the parameter is omitted, or true, user namespacing is turned on. The UID/GID range to
680 use is determined automatically from the file ownership of the root directory of the container's directory
681 tree. To use this option, make sure to prepare the directory tree in advance, and ensure that all files and
682 directories in it are owned by UIDs/GIDs in the range you'd like to use. Also, make sure that used file ACLs
683 exclusively reference UIDs/GIDs in the appropriate range. If this mode is used the number of UIDs/GIDs
684 assigned to the container for use is
65536, and the UID/GID of the root directory must be a multiple of
685 65536.
</para></listitem>
687 <listitem><para>If the parameter is false, user namespacing is turned off. This is the default.
</para>
690 <listitem><para>The special value
<literal>pick
</literal> turns on user namespacing. In this case the UID/GID
691 range is automatically chosen. As first step, the file owner of the root directory of the container's
692 directory tree is read, and it is checked that it is currently not used by the system otherwise (in
693 particular, that no other container is using it). If this check is successful, the UID/GID range determined
694 this way is used, similar to the behavior if
"yes" is specified. If the check is not successful (and thus
695 the UID/GID range indicated in the root directory's file owner is already used elsewhere) a new – currently
696 unused – UID/GID range of
65536 UIDs/GIDs is randomly chosen between the host UID/GIDs of
524288 and
697 1878982656, always starting at a multiple of
65536. This setting implies
698 <option>--private-users-chown
</option> (see below), which has the effect that the files and directories in
699 the container's directory tree will be owned by the appropriate users of the range picked. Using this option
700 makes user namespace behavior fully automatic. Note that the first invocation of a previously unused
701 container image might result in picking a new UID/GID range for it, and thus in the (possibly expensive) file
702 ownership adjustment operation. However, subsequent invocations of the container will be cheap (unless of
703 course the picked UID/GID range is assigned to a different use by then).
</para></listitem>
706 <para>It is recommended to assign at least
65536 UIDs/GIDs to each container, so that the usable UID/GID range in the
707 container covers
16 bit. For best security, do not assign overlapping UID/GID ranges to multiple containers. It is
708 hence a good idea to use the upper
16 bit of the host
32-bit UIDs/GIDs as container identifier, while the lower
16
709 bit encode the container UID/GID used. This is in fact the behavior enforced by the
710 <option>--private-users=pick
</option> option.
</para>
712 <para>When user namespaces are used, the GID range assigned to each container is always chosen identical to the
715 <para>In most cases, using
<option>--private-users=pick
</option> is the recommended option as it enhances
716 container security massively and operates fully automatically in most cases.
</para>
718 <para>Note that the picked UID/GID range is not written to
<filename>/etc/passwd
</filename> or
719 <filename>/etc/group
</filename>. In fact, the allocation of the range is not stored persistently anywhere,
720 except in the file ownership of the files and directories of the container.
</para>
722 <para>Note that when user namespacing is used file ownership on disk reflects this, and all of the container's
723 files and directories are owned by the container's effective user and group IDs. This means that copying files
724 from and to the container image requires correction of the numeric UID/GID values, according to the UID/GID
725 shift applied.
</para></listitem>
729 <term><option>--private-users-chown
</option></term>
731 <listitem><para>If specified, all files and directories in the container's directory tree will be
732 adjusted so that they are owned by the appropriate UIDs/GIDs selected for the container (see above).
733 This operation is potentially expensive, as it involves iterating through the full directory tree of
734 the container. Besides actual file ownership, file ACLs are adjusted as well.
</para>
736 <para>This option is implied if
<option>--private-users=pick
</option> is used. This option has no effect if
737 user namespacing is not used.
</para></listitem>
741 <term><option>-U
</option></term>
743 <listitem><para>If the kernel supports the user namespaces feature, equivalent to
744 <option>--private-users=pick --private-users-chown
</option>, otherwise equivalent to
745 <option>--private-users=no
</option>.
</para>
747 <para>Note that
<option>-U
</option> is the default if the
748 <filename>systemd-nspawn@.service
</filename> template unit file is used.
</para>
750 <para>Note: it is possible to undo the effect of
<option>--private-users-chown
</option> (or
751 <option>-U
</option>) on the file system by redoing the operation with the first UID of
0:
</para>
753 <programlisting>systemd-nspawn … --private-users=
0 --private-users-chown
</programlisting>
759 </refsect2><refsect2>
760 <title>Networking Options
</title>
765 <term><option>--private-network
</option></term>
767 <listitem><para>Disconnect networking of the container from
768 the host. This makes all network interfaces unavailable in the
769 container, with the exception of the loopback device and those
770 specified with
<option>--network-interface=
</option> and
771 configured with
<option>--network-veth
</option>. If this
772 option is specified, the
<constant>CAP_NET_ADMIN
</constant> capability will be
773 added to the set of capabilities the container retains. The
774 latter may be disabled by using
<option>--drop-capability=
</option>.
775 If this option is not specified (or implied by one of the options
776 listed below), the container will have full access to the host network.
781 <term><option>--network-interface=
</option></term>
783 <listitem><para>Assign the specified network interface to the
784 container. This will remove the specified interface from the
785 calling namespace and place it in the container. When the
786 container terminates, it is moved back to the host namespace.
787 Note that
<option>--network-interface=
</option> implies
788 <option>--private-network
</option>. This option may be used
789 more than once to add multiple network interfaces to the
790 container.
</para></listitem>
794 <term><option>--network-macvlan=
</option></term>
796 <listitem><para>Create a
<literal>macvlan
</literal> interface
797 of the specified Ethernet network interface and add it to the
798 container. A
<literal>macvlan
</literal> interface is a virtual
799 interface that adds a second MAC address to an existing
800 physical Ethernet link. The interface in the container will be
801 named after the interface on the host, prefixed with
802 <literal>mv-
</literal>. Note that
803 <option>--network-macvlan=
</option> implies
804 <option>--private-network
</option>. This option may be used
805 more than once to add multiple network interfaces to the
806 container.
</para></listitem>
810 <term><option>--network-ipvlan=
</option></term>
812 <listitem><para>Create an
<literal>ipvlan
</literal> interface
813 of the specified Ethernet network interface and add it to the
814 container. An
<literal>ipvlan
</literal> interface is a virtual
815 interface, similar to a
<literal>macvlan
</literal> interface,
816 which uses the same MAC address as the underlying interface.
817 The interface in the container will be named after the
818 interface on the host, prefixed with
<literal>iv-
</literal>.
819 Note that
<option>--network-ipvlan=
</option> implies
820 <option>--private-network
</option>. This option may be used
821 more than once to add multiple network interfaces to the
822 container.
</para></listitem>
826 <term><option>-n
</option></term>
827 <term><option>--network-veth
</option></term>
829 <listitem><para>Create a virtual Ethernet link (
<literal>veth
</literal>) between host and container. The host
830 side of the Ethernet link will be available as a network interface named after the container's name (as
831 specified with
<option>--machine=
</option>), prefixed with
<literal>ve-
</literal>. The container side of the
832 Ethernet link will be named
<literal>host0
</literal>. The
<option>--network-veth
</option> option implies
833 <option>--private-network
</option>.
</para>
836 <citerefentry><refentrytitle>systemd-networkd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
837 includes by default a network file
<filename>/usr/lib/systemd/network/
80-container-ve.network
</filename>
838 matching the host-side interfaces created this way, which contains settings to enable automatic address
839 provisioning on the created virtual link via DHCP, as well as automatic IP routing onto the host's external
840 network interfaces. It also contains
<filename>/usr/lib/systemd/network/
80-container-host0.network
</filename>
841 matching the container-side interface created this way, containing settings to enable client side address
842 assignment via DHCP. In case
<filename>systemd-networkd
</filename> is running on both the host and inside the
843 container, automatic IP communication from the container to the host is thus available, with further
844 connectivity to the external network.
</para>
846 <para>Note that
<option>--network-veth
</option> is the default if the
847 <filename>systemd-nspawn@.service
</filename> template unit file is used.
</para>
849 <para>Note that on Linux network interface names may have a length of
15 characters at maximum, while
850 container names may have a length up to
64 characters. As this option derives the host-side interface
851 name from the container name the name is possibly truncated. Thus, care needs to be taken to ensure
852 that interface names remain unique in this case, or even better container names are generally not
853 chosen longer than
12 characters, to avoid the truncation. If the name is truncated,
854 <command>systemd-nspawn
</command> will automatically append a
4-digit hash value to the name to
855 reduce the chance of collisions. However, the hash algorithm is not collision-free. (See
856 <citerefentry><refentrytitle>systemd.net-naming-scheme
</refentrytitle><manvolnum>7</manvolnum></citerefentry>
857 for details on older naming algorithms for this interface). Alternatively, the
858 <option>--network-veth-extra=
</option> option may be used, which allows free configuration of the
859 host-side interface name independently of the container name — but might require a bit more
860 additional configuration in case bridging in a fashion similar to
<option>--network-bridge=
</option>
866 <term><option>--network-veth-extra=
</option></term>
868 <listitem><para>Adds an additional virtual Ethernet link
869 between host and container. Takes a colon-separated pair of
870 host interface name and container interface name. The latter
871 may be omitted in which case the container and host sides will
872 be assigned the same name. This switch is independent of
873 <option>--network-veth
</option>, and — in contrast — may be
874 used multiple times, and allows configuration of the network
875 interface names. Note that
<option>--network-bridge=
</option>
876 has no effect on interfaces created with
877 <option>--network-veth-extra=
</option>.
</para></listitem>
881 <term><option>--network-bridge=
</option></term>
883 <listitem><para>Adds the host side of the Ethernet link created with
<option>--network-veth
</option>
884 to the specified Ethernet bridge interface. Expects a valid network interface name of a bridge device
885 as argument. Note that
<option>--network-bridge=
</option> implies
<option>--network-veth
</option>. If
886 this option is used, the host side of the Ethernet link will use the
<literal>vb-
</literal> prefix
887 instead of
<literal>ve-
</literal>. Regardless of the used naming prefix the same network interface
888 name length limits imposed by Linux apply, along with the complications this creates (for details see
889 above).
</para></listitem>
893 <term><option>--network-zone=
</option></term>
895 <listitem><para>Creates a virtual Ethernet link (
<literal>veth
</literal>) to the container and adds it to an
896 automatically managed Ethernet bridge interface. The bridge interface is named after the passed argument,
897 prefixed with
<literal>vz-
</literal>. The bridge interface is automatically created when the first container
898 configured for its name is started, and is automatically removed when the last container configured for its
899 name exits. Hence, each bridge interface configured this way exists only as long as there's at least one
900 container referencing it running. This option is very similar to
<option>--network-bridge=
</option>, besides
901 this automatic creation/removal of the bridge device.
</para>
903 <para>This setting makes it easy to place multiple related containers on a common, virtual Ethernet-based
904 broadcast domain, here called a
"zone". Each container may only be part of one zone, but each zone may contain
905 any number of containers. Each zone is referenced by its name. Names may be chosen freely (as long as they form
906 valid network interface names when prefixed with
<literal>vz-
</literal>), and it is sufficient to pass the same
907 name to the
<option>--network-zone=
</option> switch of the various concurrently running containers to join
908 them in one zone.
</para>
911 <citerefentry><refentrytitle>systemd-networkd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
912 includes by default a network file
<filename>/usr/lib/systemd/network/
80-container-vz.network
</filename>
913 matching the bridge interfaces created this way, which contains settings to enable automatic address
914 provisioning on the created virtual network via DHCP, as well as automatic IP routing onto the host's external
915 network interfaces. Using
<option>--network-zone=
</option> is hence in most cases fully automatic and
916 sufficient to connect multiple local containers in a joined broadcast domain to the host, with further
917 connectivity to the external network.
</para>
922 <term><option>--network-namespace-path=
</option></term>
924 <listitem><para>Takes the path to a file representing a kernel
925 network namespace that the container shall run in. The specified path
926 should refer to a (possibly bind-mounted) network namespace file, as
927 exposed by the kernel below
<filename>/proc/$PID/ns/net
</filename>.
928 This makes the container enter the given network namespace. One of the
929 typical use cases is to give a network namespace under
930 <filename>/run/netns
</filename> created by
<citerefentry
931 project='man-pages'
><refentrytitle>ip-netns
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
932 for example,
<option>--network-namespace-path=/run/netns/foo
</option>.
933 Note that this option cannot be used together with other
934 network-related options, such as
<option>--private-network
</option>
935 or
<option>--network-interface=
</option>.
</para></listitem>
939 <term><option>-p
</option></term>
940 <term><option>--port=
</option></term>
942 <listitem><para>If private networking is enabled, maps an IP
943 port on the host onto an IP port on the container. Takes a
944 protocol specifier (either
<literal>tcp
</literal> or
945 <literal>udp
</literal>), separated by a colon from a host port
946 number in the range
1 to
65535, separated by a colon from a
947 container port number in the range from
1 to
65535. The
948 protocol specifier and its separating colon may be omitted, in
949 which case
<literal>tcp
</literal> is assumed. The container
950 port number and its colon may be omitted, in which case the
951 same port as the host port is implied. This option is only
952 supported if private networking is used, such as with
953 <option>--network-veth
</option>,
<option>--network-zone=
</option>
954 <option>--network-bridge=
</option>.
</para></listitem>
958 </refsect2><refsect2>
959 <title>Security Options
</title>
963 <term><option>--capability=
</option></term>
965 <listitem><para>List one or more additional capabilities to grant the container. Takes a
966 comma-separated list of capability names, see
<citerefentry
967 project='man-pages'
><refentrytitle>capabilities
</refentrytitle><manvolnum>7</manvolnum></citerefentry>
968 for more information. Note that the following capabilities will be granted in any way:
969 <constant>CAP_AUDIT_CONTROL
</constant>,
<constant>CAP_AUDIT_WRITE
</constant>,
970 <constant>CAP_CHOWN
</constant>,
<constant>CAP_DAC_OVERRIDE
</constant>,
971 <constant>CAP_DAC_READ_SEARCH
</constant>,
<constant>CAP_FOWNER
</constant>,
972 <constant>CAP_FSETID
</constant>,
<constant>CAP_IPC_OWNER
</constant>,
<constant>CAP_KILL
</constant>,
973 <constant>CAP_LEASE
</constant>,
<constant>CAP_LINUX_IMMUTABLE
</constant>,
974 <constant>CAP_MKNOD
</constant>,
<constant>CAP_NET_BIND_SERVICE
</constant>,
975 <constant>CAP_NET_BROADCAST
</constant>,
<constant>CAP_NET_RAW
</constant>,
976 <constant>CAP_SETFCAP
</constant>,
<constant>CAP_SETGID
</constant>,
<constant>CAP_SETPCAP
</constant>,
977 <constant>CAP_SETUID
</constant>,
<constant>CAP_SYS_ADMIN
</constant>,
978 <constant>CAP_SYS_BOOT
</constant>,
<constant>CAP_SYS_CHROOT
</constant>,
979 <constant>CAP_SYS_NICE
</constant>,
<constant>CAP_SYS_PTRACE
</constant>,
980 <constant>CAP_SYS_RESOURCE
</constant>,
<constant>CAP_SYS_TTY_CONFIG
</constant>. Also
981 <constant>CAP_NET_ADMIN
</constant> is retained if
<option>--private-network
</option> is specified.
982 If the special value
<literal>all
</literal> is passed, all capabilities are retained.
</para>
984 <para>If the special value of
<literal>help
</literal> is passed, the program will print known
985 capability names and exit.
</para></listitem>
989 <term><option>--drop-capability=
</option></term>
991 <listitem><para>Specify one or more additional capabilities to
992 drop for the container. This allows running the container with
993 fewer capabilities than the default (see
996 <para>If the special value of
<literal>help
</literal> is passed, the program will print known
997 capability names and exit.
</para></listitem>
1001 <term><option>--no-new-privileges=
</option></term>
1003 <listitem><para>Takes a boolean argument. Specifies the value of the
<constant>PR_SET_NO_NEW_PRIVS
</constant>
1004 flag for the container payload. Defaults to off. When turned on the payload code of the container cannot
1005 acquire new privileges, i.e. the
"setuid" file bit as well as file system capabilities will not have an effect
1006 anymore. See
<citerefentry
1007 project='man-pages'
><refentrytitle>prctl
</refentrytitle><manvolnum>2</manvolnum></citerefentry> for details
1008 about this flag.
</para></listitem>
1012 <term><option>--system-call-filter=
</option></term>
1014 <listitem><para>Alter the system call filter applied to containers. Takes a space-separated list of system call
1015 names or group names (the latter prefixed with
<literal>@
</literal>, as listed by the
1016 <command>syscall-filter
</command> command of
1017 <citerefentry><refentrytitle>systemd-analyze
</refentrytitle><manvolnum>1</manvolnum></citerefentry>). Passed
1018 system calls will be permitted. The list may optionally be prefixed by
<literal>~
</literal>, in which case all
1019 listed system calls are prohibited. If this command line option is used multiple times the configured lists are
1020 combined. If both a positive and a negative list (that is one system call list without and one with the
1021 <literal>~
</literal> prefix) are configured, the negative list takes precedence over the positive list. Note
1022 that
<command>systemd-nspawn
</command> always implements a system call whitelist (as opposed to a blacklist),
1023 and this command line option hence adds or removes entries from the default whitelist, depending on the
1024 <literal>~
</literal> prefix. Note that the applied system call filter is also altered implicitly if additional
1025 capabilities are passed using the
<command>--capabilities=
</command>.
</para></listitem>
1029 <term><option>-Z
</option></term>
1030 <term><option>--selinux-context=
</option></term>
1032 <listitem><para>Sets the SELinux security context to be used
1033 to label processes in the container.
</para>
1038 <term><option>-L
</option></term>
1039 <term><option>--selinux-apifs-context=
</option></term>
1041 <listitem><para>Sets the SELinux security context to be used
1042 to label files in the virtual API file systems in the
1048 </refsect2><refsect2>
1049 <title>Resource Options
</title>
1054 <term><option>--rlimit=
</option></term>
1056 <listitem><para>Sets the specified POSIX resource limit for the container payload. Expects an assignment of the
1058 <literal><replaceable>LIMIT
</replaceable>=
<replaceable>SOFT
</replaceable>:
<replaceable>HARD
</replaceable></literal>
1059 or
<literal><replaceable>LIMIT
</replaceable>=
<replaceable>VALUE
</replaceable></literal>, where
1060 <replaceable>LIMIT
</replaceable> should refer to a resource limit type, such as
1061 <constant>RLIMIT_NOFILE
</constant> or
<constant>RLIMIT_NICE
</constant>. The
<replaceable>SOFT
</replaceable> and
1062 <replaceable>HARD
</replaceable> fields should refer to the numeric soft and hard resource limit values. If the
1063 second form is used,
<replaceable>VALUE
</replaceable> may specify a value that is used both as soft and hard
1064 limit. In place of a numeric value the special string
<literal>infinity
</literal> may be used to turn off
1065 resource limiting for the specific type of resource. This command line option may be used multiple times to
1066 control limits on multiple limit types. If used multiple times for the same limit type, the last use
1067 wins. For details about resource limits see
<citerefentry
1068 project='man-pages'
><refentrytitle>setrlimit
</refentrytitle><manvolnum>2</manvolnum></citerefentry>. By default
1069 resource limits for the container's init process (PID
1) are set to the same values the Linux kernel originally
1070 passed to the host init system. Note that some resource limits are enforced on resources counted per user, in
1071 particular
<constant>RLIMIT_NPROC
</constant>. This means that unless user namespacing is deployed
1072 (i.e.
<option>--private-users=
</option> is used, see above), any limits set will be applied to the resource
1073 usage of the same user on all local containers as well as the host. This means particular care needs to be
1074 taken with these limits as they might be triggered by possibly less trusted code. Example:
1075 <literal>--rlimit=RLIMIT_NOFILE=
8192:
16384</literal>.
</para></listitem>
1079 <term><option>--oom-score-adjust=
</option></term>
1081 <listitem><para>Changes the OOM (
"Out Of Memory") score adjustment value for the container payload. This controls
1082 <filename>/proc/self/oom_score_adj
</filename> which influences the preference with which this container is
1083 terminated when memory becomes scarce. For details see
<citerefentry
1084 project='man-pages'
><refentrytitle>proc
</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Takes an
1085 integer in the range -
1000…
1000.
</para></listitem>
1089 <term><option>--cpu-affinity=
</option></term>
1091 <listitem><para>Controls the CPU affinity of the container payload. Takes a comma separated list of CPU numbers
1092 or number ranges (the latter's start and end value separated by dashes). See
<citerefentry
1093 project='man-pages'
><refentrytitle>sched_setaffinity
</refentrytitle><manvolnum>2</manvolnum></citerefentry> for
1094 details.
</para></listitem>
1098 <term><option>--personality=
</option></term>
1100 <listitem><para>Control the architecture (
"personality")
1102 <citerefentry project='man-pages'
><refentrytitle>uname
</refentrytitle><manvolnum>2</manvolnum></citerefentry>
1103 in the container. Currently, only
<literal>x86
</literal> and
1104 <literal>x86-
64</literal> are supported. This is useful when
1105 running a
32-bit container on a
64-bit host. If this setting
1106 is not used, the personality reported in the container is the
1107 same as the one reported on the host.
</para></listitem>
1111 </refsect2><refsect2>
1112 <title>Integration Options
</title>
1116 <term><option>--resolv-conf=
</option></term>
1118 <listitem><para>Configures how
<filename>/etc/resolv.conf
</filename> inside of the container shall be
1119 handled (i.e. DNS configuration synchronization from host to container). Takes one of
1120 <literal>off
</literal>,
<literal>copy-host
</literal>,
<literal>copy-static
</literal>,
1121 <literal>copy-uplink
</literal>,
<literal>copy-stub
</literal>,
<literal>replace-host
</literal>,
1122 <literal>replace-static
</literal>,
<literal>replace-uplink
</literal>,
1123 <literal>replace-stub
</literal>,
<literal>bind-host
</literal>,
<literal>bind-static
</literal>,
1124 <literal>bind-uplink
</literal>,
<literal>bind-stub
</literal>,
<literal>delete
</literal> or
1125 <literal>auto
</literal>.
</para>
1127 <para>If set to
<literal>off
</literal> the
<filename>/etc/resolv.conf
</filename> file in the
1128 container is left as it is included in the image, and neither modified nor bind mounted over.
</para>
1130 <para>If set to
<literal>copy-host
</literal>, the
<filename>/etc/resolv.conf
</filename> file from the
1131 host is copied into the container, unless the file exists already and is not a regular file (e.g. a
1132 symlink). Similar, if
<literal>replace-host
</literal> is used the file is copied, replacing any
1133 existing inode, including symlinks. Similar, if
<literal>bind-host
</literal> is used, the file is
1134 bind mounted from the host into the container.
</para>
1136 <para>If set to
<literal>copy-static
</literal>,
<literal>replace-static
</literal> or
1137 <literal>bind-static
</literal> the static
<filename>resolv.conf
</filename> file supplied with
1138 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
1139 (specifically:
<filename>/usr/lib/systemd/resolv.conf
</filename>) is copied or bind mounted into the
1142 <para>If set to
<literal>copy-uplink
</literal>,
<literal>replace-uplink
</literal> or
1143 <literal>bind-uplink
</literal> the uplink
<filename>resolv.conf
</filename> file managed by
1144 <filename>systemd-resolved.service
</filename> (specifically:
1145 <filename>/run/systemd/resolve/resolv.conf
</filename>) is copied or bind mounted into the
1148 <para>If set to
<literal>copy-stub
</literal>,
<literal>replace-stub
</literal> or
1149 <literal>bind-stub
</literal> the stub
<filename>resolv.conf
</filename> file managed by
1150 <filename>systemd-resolved.service
</filename> (specifically:
1151 <filename>/run/systemd/resolve/stub-resolv.conf
</filename>) is copied or bind mounted into the
1154 <para>If set to
<literal>delete
</literal> the
<filename>/etc/resolv.conf
</filename> file in the
1155 container is deleted if it exists.
</para>
1157 <para>Finally, if set to
<literal>auto
</literal> the file is left as it is if private networking is
1158 turned on (see
<option>--private-network
</option>). Otherwise, if
1159 <filename>systemd-resolved.service
</filename> is connectible its stub
1160 <filename>resolv.conf
</filename> file is used, and if not the host's
1161 <filename>/etc/resolv.conf
</filename> file is used. In the latter cases the file is copied if the
1162 image is writable, and bind mounted otherwise.
</para>
1164 <para>It's recommended to use
<literal>copy-…
</literal> or
<literal>replace-…
</literal> if the
1165 container shall be able to make changes to the DNS configuration on its own, deviating from the
1166 host's settings. Otherwise
<literal>bind
</literal> is preferable, as it means direct changes to
1167 <filename>/etc/resolv.conf
</filename> in the container are not allowed, as it is a read-only bind
1168 mount (but note that if the container has enough privileges, it might simply go ahead and unmount the
1169 bind mount anyway). Note that both if the file is bind mounted and if it is copied no further
1170 propagation of configuration is generally done after the one-time early initialization (this is
1171 because the file is usually updated through copying and renaming). Defaults to
1172 <literal>auto
</literal>.
</para></listitem>
1176 <term><option>--timezone=
</option></term>
1178 <listitem><para>Configures how
<filename>/etc/localtime
</filename> inside of the container (i.e. local timezone
1179 synchronization from host to container) shall be handled. Takes one of
<literal>off
</literal>,
1180 <literal>copy
</literal>,
<literal>bind
</literal>,
<literal>symlink
</literal>,
<literal>delete
</literal> or
1181 <literal>auto
</literal>. If set to
<literal>off
</literal> the
<filename>/etc/localtime
</filename> file in the
1182 container is left as it is included in the image, and neither modified nor bind mounted over. If set to
1183 <literal>copy
</literal> the
<filename>/etc/localtime
</filename> file of the host is copied into the
1184 container. Similar, if
<literal>bind
</literal> is used, it is bind mounted from the host into the container. If
1185 set to
<literal>symlink
</literal> a symlink from
<filename>/etc/localtime
</filename> in the container is
1186 created pointing to the matching the timezone file of the container that matches the timezone setting on the
1187 host. If set to
<literal>delete
</literal> the file in the container is deleted, should it exist. If set to
1188 <literal>auto
</literal> and the
<filename>/etc/localtime
</filename> file of the host is a symlink, then
1189 <literal>symlink
</literal> mode is used, and
<literal>copy
</literal> otherwise, except if the image is
1190 read-only in which case
<literal>bind
</literal> is used instead. Defaults to
1191 <literal>auto
</literal>.
</para></listitem>
1195 <term><option>--link-journal=
</option></term>
1197 <listitem><para>Control whether the container's journal shall
1198 be made visible to the host system. If enabled, allows viewing
1199 the container's journal files from the host (but not vice
1200 versa). Takes one of
<literal>no
</literal>,
1201 <literal>host
</literal>,
<literal>try-host
</literal>,
1202 <literal>guest
</literal>,
<literal>try-guest
</literal>,
1203 <literal>auto
</literal>. If
<literal>no
</literal>, the journal
1204 is not linked. If
<literal>host
</literal>, the journal files
1205 are stored on the host file system (beneath
1206 <filename>/var/log/journal/
<replaceable>machine-id
</replaceable></filename>)
1207 and the subdirectory is bind-mounted into the container at the
1208 same location. If
<literal>guest
</literal>, the journal files
1209 are stored on the guest file system (beneath
1210 <filename>/var/log/journal/
<replaceable>machine-id
</replaceable></filename>)
1211 and the subdirectory is symlinked into the host at the same
1212 location.
<literal>try-host
</literal> and
1213 <literal>try-guest
</literal> do the same but do not fail if
1214 the host does not have persistent journaling enabled. If
1215 <literal>auto
</literal> (the default), and the right
1216 subdirectory of
<filename>/var/log/journal
</filename> exists,
1217 it will be bind mounted into the container. If the
1218 subdirectory does not exist, no linking is performed.
1219 Effectively, booting a container once with
1220 <literal>guest
</literal> or
<literal>host
</literal> will link
1221 the journal persistently if further on the default of
1222 <literal>auto
</literal> is used.
</para>
1224 <para>Note that
<option>--link-journal=try-guest
</option> is the default if the
1225 <filename>systemd-nspawn@.service
</filename> template unit file is used.
</para></listitem>
1229 <term><option>-j
</option></term>
1231 <listitem><para>Equivalent to
1232 <option>--link-journal=try-guest
</option>.
</para></listitem>
1237 </refsect2><refsect2>
1238 <title>Mount Options
</title>
1243 <term><option>--bind=
</option></term>
1244 <term><option>--bind-ro=
</option></term>
1246 <listitem><para>Bind mount a file or directory from the host into the container. Takes one of: a path
1247 argument — in which case the specified path will be mounted from the host to the same path in the container, or
1248 a colon-separated pair of paths — in which case the first specified path is the source in the host, and the
1249 second path is the destination in the container, or a colon-separated triple of source path, destination path
1250 and mount options. The source path may optionally be prefixed with a
<literal>+
</literal> character. If so, the
1251 source path is taken relative to the image's root directory. This permits setting up bind mounts within the
1252 container image. The source path may be specified as empty string, in which case a temporary directory below
1253 the host's
<filename>/var/tmp
</filename> directory is used. It is automatically removed when the container is
1254 shut down. Mount options are comma-separated and currently, only
<option>rbind
</option> and
1255 <option>norbind
</option> are allowed, controlling whether to create a recursive or a regular bind
1256 mount. Defaults to
"rbind". Backslash escapes are interpreted, so
<literal>\:
</literal> may be used to embed
1257 colons in either path. This option may be specified multiple times for creating multiple independent bind
1258 mount points. The
<option>--bind-ro=
</option> option creates read-only bind mounts.
</para>
1260 <para>Note that when this option is used in combination with
<option>--private-users
</option>, the resulting
1261 mount points will be owned by the
<constant>nobody
</constant> user. That's because the mount and its files and
1262 directories continue to be owned by the relevant host users and groups, which do not exist in the container,
1263 and thus show up under the wildcard UID
65534 (nobody). If such bind mounts are created, it is recommended to
1264 make them read-only, using
<option>--bind-ro=
</option>.
</para></listitem>
1268 <term><option>--inaccessible=
</option></term>
1270 <listitem><para>Make the specified path inaccessible in the container. This over-mounts the specified path
1271 (which must exist in the container) with a file node of the same type that is empty and has the most
1272 restrictive access mode supported. This is an effective way to mask files, directories and other file system
1273 objects from the container payload. This option may be used more than once in case all specified paths are
1274 masked.
</para></listitem>
1278 <term><option>--tmpfs=
</option></term>
1280 <listitem><para>Mount a tmpfs file system into the container. Takes a single absolute path argument that
1281 specifies where to mount the tmpfs instance to (in which case the directory access mode will be chosen as
0755,
1282 owned by root/root), or optionally a colon-separated pair of path and mount option string that is used for
1283 mounting (in which case the kernel default for access mode and owner will be chosen, unless otherwise
1284 specified). Backslash escapes are interpreted in the path, so
<literal>\:
</literal> may be used to embed colons
1287 <para>Note that this option cannot be used to replace the root file system of the container with a temporary
1288 file system. However, the
<option>--volatile=
</option> option described below provides similar
1289 functionality, with a focus on implementing stateless operating system images.
</para></listitem>
1293 <term><option>--overlay=
</option></term>
1294 <term><option>--overlay-ro=
</option></term>
1296 <listitem><para>Combine multiple directory trees into one
1297 overlay file system and mount it into the container. Takes a
1298 list of colon-separated paths to the directory trees to
1299 combine and the destination mount point.
</para>
1301 <para>Backslash escapes are interpreted in the paths, so
1302 <literal>\:
</literal> may be used to embed colons in the paths.
1305 <para>If three or more paths are specified, then the last
1306 specified path is the destination mount point in the
1307 container, all paths specified before refer to directory trees
1308 on the host and are combined in the specified order into one
1309 overlay file system. The left-most path is hence the lowest
1310 directory tree, the second-to-last path the highest directory
1311 tree in the stacking order. If
<option>--overlay-ro=
</option>
1312 is used instead of
<option>--overlay=
</option>, a read-only
1313 overlay file system is created. If a writable overlay file
1314 system is created, all changes made to it are written to the
1315 highest directory tree in the stacking order, i.e. the
1316 second-to-last specified.
</para>
1318 <para>If only two paths are specified, then the second
1319 specified path is used both as the top-level directory tree in
1320 the stacking order as seen from the host, as well as the mount
1321 point for the overlay file system in the container. At least
1322 two paths have to be specified.
</para>
1324 <para>The source paths may optionally be prefixed with
<literal>+
</literal> character. If so they are taken
1325 relative to the image's root directory. The uppermost source path may also be specified as empty string, in
1326 which case a temporary directory below the host's
<filename>/var/tmp
</filename> is used. The directory is
1327 removed automatically when the container is shut down. This behaviour is useful in order to make read-only
1328 container directories writable while the container is running. For example, use the
1329 <literal>--overlay=+/var::/var
</literal> option in order to automatically overlay a writable temporary
1330 directory on a read-only
<filename>/var
</filename> directory.
</para>
1332 <para>For details about overlay file systems, see
<ulink
1333 url=
"https://www.kernel.org/doc/Documentation/filesystems/overlayfs.txt">overlayfs.txt
</ulink>. Note
1334 that the semantics of overlay file systems are substantially
1335 different from normal file systems, in particular regarding
1336 reported device and inode information. Device and inode
1337 information may change for a file while it is being written
1338 to, and processes might see out-of-date versions of files at
1339 times. Note that this switch automatically derives the
1340 <literal>workdir=
</literal> mount option for the overlay file
1341 system from the top-level directory tree, making it a sibling
1342 of it. It is hence essential that the top-level directory tree
1343 is not a mount point itself (since the working directory must
1344 be on the same file system as the top-most directory
1345 tree). Also note that the
<literal>lowerdir=
</literal> mount
1346 option receives the paths to stack in the opposite order of
1349 <para>Note that this option cannot be used to replace the root file system of the container with an overlay
1350 file system. However, the
<option>--volatile=
</option> option described above provides similar functionality,
1351 with a focus on implementing stateless operating system images.
</para></listitem>
1355 </refsect2><refsect2>
1356 <title>Input/Output Options
</title>
1360 <term><option>--console=
</option><replaceable>MODE
</replaceable></term>
1362 <listitem><para>Configures how to set up standard input, output and error output for the container
1363 payload, as well as the
<filename>/dev/console
</filename> device for the container. Takes one of
1364 <option>interactive
</option>,
<option>read-only
</option>,
<option>passive
</option>, or
1365 <option>pipe
</option>. If
<option>interactive
</option>, a pseudo-TTY is allocated and made available
1366 as
<filename>/dev/console
</filename> in the container. It is then bi-directionally connected to the
1367 standard input and output passed to
<command>systemd-nspawn
</command>.
<option>read-only
</option> is
1368 similar but only the output of the container is propagated and no input from the caller is read. If
1369 <option>passive
</option>, a pseudo TTY is allocated, but it is not connected anywhere. Finally, in
1370 <option>pipe
</option> mode no pseudo TTY is allocated, but the standard input, output and error
1371 output file descriptors passed to
<command>systemd-nspawn
</command> are passed on — as they are — to
1372 the container payload, see the following paragraph. Defaults to
<option>interactive
</option> if
1373 <command>systemd-nspawn
</command> is invoked from a terminal, and
<option>read-only
</option>
1376 <para>In
<option>pipe
</option> mode,
<filename>/dev/console
</filename> will not exist in the
1377 container. This means that the container payload generally cannot be a full init system as init
1378 systems tend to require
<filename>/dev/console
</filename> to be available. On the other hand, in this
1379 mode container invocations can be used within shell pipelines. This is because intermediary pseudo
1380 TTYs do not permit independent bidirectional propagation of the end-of-file (EOF) condition, which is
1381 necessary for shell pipelines to work correctly.
<emphasis>Note that the
<option>pipe
</option> mode
1382 should be used carefully
</emphasis>, as passing arbitrary file descriptors to less trusted container
1383 payloads might open up unwanted interfaces for access by the container payload. For example, if a
1384 passed file descriptor refers to a TTY of some form, APIs such as
<constant>TIOCSTI
</constant> may be
1385 used to synthesize input that might be used for escaping the container. Hence
<option>pipe
</option>
1386 mode should only be used if the payload is sufficiently trusted or when the standard
1387 input/output/error output file descriptors are known safe, for example pipes.
</para></listitem>
1391 <term><option>--pipe
</option></term>
1392 <term><option>-P
</option></term>
1394 <listitem><para>Equivalent to
<option>--console=pipe
</option>.
</para></listitem>
1397 <xi:include href=
"standard-options.xml" xpointer=
"no-pager" />
1398 <xi:include href=
"standard-options.xml" xpointer=
"help" />
1399 <xi:include href=
"standard-options.xml" xpointer=
"version" />
1404 <xi:include href=
"less-variables.xml" />
1407 <title>Examples
</title>
1411 <ulink url=
"https://getfedora.org">Fedora
</ulink> image and start a shell in it
</title>
1413 <programlisting># machinectl pull-raw --verify=no \
1414 https://download.fedoraproject.org/pub/fedora/linux/releases/
&fedora_latest_version;/Cloud/x86_64/images/Fedora-Cloud-Base-
&fedora_latest_version;-
&fedora_cloud_release;.x86_64.raw.xz \
1415 Fedora-Cloud-Base-
&fedora_latest_version;-
&fedora_cloud_release;.x86-
64
1416 # systemd-nspawn -M Fedora-Cloud-Base-
&fedora_latest_version;-
&fedora_cloud_release;.x86-
64</programlisting>
1418 <para>This downloads an image using
1419 <citerefentry><refentrytitle>machinectl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
1420 and opens a shell in it.
</para>
1424 <title>Build and boot a minimal Fedora distribution in a container
</title>
1426 <programlisting># dnf -y --releasever=
&fedora_latest_version; --installroot=/var/lib/machines/f
&fedora_latest_version; \
1427 --disablerepo='*' --enablerepo=fedora --enablerepo=updates install \
1428 systemd passwd dnf fedora-release vim-minimal glibc-minimal-langpack
1429 # systemd-nspawn -bD /var/lib/machines/f
&fedora_latest_version;</programlisting>
1431 <para>This installs a minimal Fedora distribution into the
1432 directory
<filename index=
"false">/var/lib/machines/f
&fedora_latest_version;</filename>
1433 and then boots an OS in a namespace container in it. Because the installation
1434 is located underneath the standard
<filename>/var/lib/machines/
</filename>
1435 directory, it is also possible to start the machine using
1436 <command>systemd-nspawn -M f
&fedora_latest_version;</command>.
</para>
1440 <title>Spawn a shell in a container of a minimal Debian unstable distribution
</title>
1442 <programlisting># debootstrap unstable ~/debian-tree/
1443 # systemd-nspawn -D ~/debian-tree/
</programlisting>
1445 <para>This installs a minimal Debian unstable distribution into
1446 the directory
<filename>~/debian-tree/
</filename> and then
1447 spawns a shell in a namespace container in it.
</para>
1449 <para><command>debootstrap
</command> supports
1450 <ulink url=
"https://www.debian.org">Debian
</ulink>,
1451 <ulink url=
"https://www.ubuntu.com">Ubuntu
</ulink>,
1452 and
<ulink url=
"https://www.tanglu.org">Tanglu
</ulink>
1453 out of the box, so the same command can be used to install any of those. For other
1454 distributions from the Debian family, a mirror has to be specified, see
1455 <citerefentry project='die-net'
><refentrytitle>debootstrap
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
1460 <title>Boot a minimal
1461 <ulink url=
"https://www.archlinux.org">Arch Linux
</ulink> distribution in a container
</title>
1463 <programlisting># pacstrap -c ~/arch-tree/ base
1464 # systemd-nspawn -bD ~/arch-tree/
</programlisting>
1466 <para>This installs a minimal Arch Linux distribution into the
1467 directory
<filename>~/arch-tree/
</filename> and then boots an OS
1468 in a namespace container in it.
</para>
1473 <ulink url=
"https://software.opensuse.org/distributions/tumbleweed">OpenSUSE Tumbleweed
</ulink>
1474 rolling distribution
</title>
1476 <programlisting># zypper --root=/var/lib/machines/tumbleweed ar -c \
1477 https://download.opensuse.org/tumbleweed/repo/oss tumbleweed
1478 # zypper --root=/var/lib/machines/tumbleweed refresh
1479 # zypper --root=/var/lib/machines/tumbleweed install --no-recommends \
1480 systemd shadow zypper openSUSE-release vim
1481 # systemd-nspawn -M tumbleweed passwd root
1482 # systemd-nspawn -M tumbleweed -b
</programlisting>
1486 <title>Boot into an ephemeral snapshot of the host system
</title>
1488 <programlisting># systemd-nspawn -D / -xb
</programlisting>
1490 <para>This runs a copy of the host system in a snapshot which is removed immediately when the container
1491 exits. All file system changes made during runtime will be lost on shutdown, hence.
</para>
1495 <title>Run a container with SELinux sandbox security contexts
</title>
1497 <programlisting># chcon system_u:object_r:svirt_sandbox_file_t:s0:c0,c1 -R /srv/container
1498 # systemd-nspawn -L system_u:object_r:svirt_sandbox_file_t:s0:c0,c1 \
1499 -Z system_u:system_r:svirt_lxc_net_t:s0:c0,c1 -D /srv/container /bin/sh
</programlisting>
1503 <title>Run a container with an OSTree deployment
</title>
1505 <programlisting># systemd-nspawn -b -i ~/image.raw \
1506 --pivot-root=/ostree/deploy/$OS/deploy/$CHECKSUM:/sysroot \
1507 --bind=+/sysroot/ostree/deploy/$OS/var:/var
</programlisting>
1512 <title>Exit status
</title>
1514 <para>The exit code of the program executed in the container is
1519 <title>See Also
</title>
1521 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1522 <citerefentry><refentrytitle>systemd.nspawn
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1523 <citerefentry project='man-pages'
><refentrytitle>chroot
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1524 <citerefentry project='mankier'
><refentrytitle>dnf
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1525 <citerefentry project='die-net'
><refentrytitle>debootstrap
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1526 <citerefentry project='archlinux'
><refentrytitle>pacman
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1527 <citerefentry project='mankier'
><refentrytitle>zypper
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1528 <citerefentry><refentrytitle>systemd.slice
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1529 <citerefentry><refentrytitle>machinectl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1530 <citerefentry project='man-pages'
><refentrytitle>btrfs
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
projects / thirdparty / systemd.git / blob