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| Copyright 2010 Lennart Poettering |
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| |
| <refentry id="systemd-nspawn" |
| xmlns:xi="http://www.w3.org/2001/XInclude"> |
| |
| <refentryinfo> |
| <title>systemd-nspawn</title> |
| <productname>systemd</productname> |
| |
| <authorgroup> |
| <author> |
| <contrib>Developer</contrib> |
| <firstname>Lennart</firstname> |
| <surname>Poettering</surname> |
| <email>lennart@poettering.net</email> |
| </author> |
| </authorgroup> |
| </refentryinfo> |
| |
| <refmeta> |
| <refentrytitle>systemd-nspawn</refentrytitle> |
| <manvolnum>1</manvolnum> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>systemd-nspawn</refname> |
| <refpurpose>Spawn a namespace container for debugging, testing and building</refpurpose> |
| </refnamediv> |
| |
| <refsynopsisdiv> |
| <cmdsynopsis> |
| <command>systemd-nspawn</command> |
| <arg choice="opt" rep="repeat">OPTIONS</arg> |
| <arg choice="opt"><replaceable>COMMAND</replaceable> |
| <arg choice="opt" rep="repeat">ARGS</arg> |
| </arg> |
| </cmdsynopsis> |
| <cmdsynopsis> |
| <command>systemd-nspawn</command> |
| <arg choice="plain">--boot</arg> |
| <arg choice="opt" rep="repeat">OPTIONS</arg> |
| <arg choice="opt" rep="repeat">ARGS</arg> |
| </cmdsynopsis> |
| </refsynopsisdiv> |
| |
| <refsect1> |
| <title>Description</title> |
| |
| <para><command>systemd-nspawn</command> may be used to run a command or OS in a light-weight namespace |
| container. In many ways it is similar to <citerefentry |
| project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry>, but more powerful |
| since it fully virtualizes the file system hierarchy, as well as the process tree, the various IPC subsystems and |
| the host and domain name.</para> |
| |
| <para><command>systemd-nspawn</command> may be invoked on any directory tree containing an operating system tree, |
| using the <option>--directory=</option> command line option. By using the <option>--machine=</option> option an OS |
| tree is automatically searched for in a couple of locations, most importantly in |
| <filename>/var/lib/machines</filename>, the suggested directory to place container images installed on the |
| system.</para> |
| |
| <para>In contrast to <citerefentry |
| project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry> <command>systemd-nspawn</command> |
| may be used to boot full Linux-based operating systems in a container.</para> |
| |
| <para><command>systemd-nspawn</command> limits access to various kernel interfaces in the container to read-only, |
| such as <filename>/sys</filename>, <filename>/proc/sys</filename> or <filename>/sys/fs/selinux</filename>. The |
| host's network interfaces and the system clock may not be changed from within the container. Device nodes may not |
| be created. The host system cannot be rebooted and kernel modules may not be loaded from within the |
| container.</para> |
| |
| <para>Use a tool like <citerefentry |
| project='mankier'><refentrytitle>dnf</refentrytitle><manvolnum>8</manvolnum></citerefentry>, <citerefentry |
| project='die-net'><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>, or |
| <citerefentry project='archlinux'><refentrytitle>pacman</refentrytitle><manvolnum>8</manvolnum></citerefentry> to |
| set up an OS directory tree suitable as file system hierarchy for <command>systemd-nspawn</command> containers. See |
| the Examples section below for details on suitable invocation of these commands.</para> |
| |
| <para>As a safety check <command>systemd-nspawn</command> will verify the existence of |
| <filename>/usr/lib/os-release</filename> or <filename>/etc/os-release</filename> in the container tree before |
| starting the container (see |
| <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry>). It might be |
| necessary to add this file to the container tree manually if the OS of the container is too old to contain this |
| file out-of-the-box.</para> |
| |
| <para><command>systemd-nspawn</command> may be invoked directly from the interactive command line or run as system |
| service in the background. In this mode each container instance runs as its own service instance; a default |
| template unit file <filename>systemd-nspawn@.service</filename> is provided to make this easy, taking the container |
| name as instance identifier. Note that different default options apply when <command>systemd-nspawn</command> is |
| invoked by the template unit file than interactively on the command line. Most importantly the template unit file |
| makes use of the <option>--boot</option> which is not the default in case <command>systemd-nspawn</command> is |
| invoked from the interactive command line. Further differences with the defaults are documented along with the |
| various supported options below.</para> |
| |
| <para>The <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> tool may |
| be used to execute a number of operations on containers. In particular it provides easy-to-use commands to run |
| containers as system services using the <filename>systemd-nspawn@.service</filename> template unit |
| file.</para> |
| |
| <para>Along with each container a settings file with the <filename>.nspawn</filename> suffix may exist, containing |
| additional settings to apply when running the container. See |
| <citerefentry><refentrytitle>systemd.nspawn</refentrytitle><manvolnum>5</manvolnum></citerefentry> for |
| details. Settings files override the default options used by the <filename>systemd-nspawn@.service</filename> |
| template unit file, making it usually unnecessary to alter this template file directly.</para> |
| |
| <para>Note that <command>systemd-nspawn</command> will mount file systems private to the container to |
| <filename>/dev</filename>, <filename>/run</filename> and similar. These will not be visible outside of the |
| container, and their contents will be lost when the container exits.</para> |
| |
| <para>Note that running two <command>systemd-nspawn</command> containers from the same directory tree will not make |
| processes in them see each other. The PID namespace separation of the two containers is complete and the containers |
| will share very few runtime objects except for the underlying file system. Use |
| <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s |
| <command>login</command> or <command>shell</command> commands to request an additional login session in a running |
| container.</para> |
| |
| <para><command>systemd-nspawn</command> implements the <ulink |
| url="https://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container Interface</ulink> |
| specification.</para> |
| |
| <para>While running, containers invoked with <command>systemd-nspawn</command> are registered with the |
| <citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>8</manvolnum></citerefentry> service that |
| keeps track of running containers, and provides programming interfaces to interact with them.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Options</title> |
| |
| <para>If option <option>-b</option> is specified, the arguments |
| are used as arguments for the init binary. Otherwise, |
| <replaceable>COMMAND</replaceable> specifies the program to launch |
| in the container, and the remaining arguments are used as |
| arguments for this program. If <option>--boot</option> is not used and |
| no arguments are specified, a shell is launched in the |
| container.</para> |
| |
| <para>The following options are understood:</para> |
| |
| <variablelist> |
| <varlistentry> |
| <term><option>-D</option></term> |
| <term><option>--directory=</option></term> |
| |
| <listitem><para>Directory to use as file system root for the |
| container.</para> |
| |
| <para>If neither <option>--directory=</option>, nor |
| <option>--image=</option> is specified the directory is |
| determined by searching for a directory named the same as the |
| machine name specified with <option>--machine=</option>. See |
| <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| section "Files and Directories" for the precise search path.</para> |
| |
| <para>If neither <option>--directory=</option>, |
| <option>--image=</option>, nor <option>--machine=</option> |
| are specified, the current directory will |
| be used. May not be specified together with |
| <option>--image=</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--template=</option></term> |
| |
| <listitem><para>Directory or <literal>btrfs</literal> subvolume to use as template for the container's root |
| directory. If this is specified and the container's root directory (as configured by |
| <option>--directory=</option>) does not yet exist it is created as <literal>btrfs</literal> snapshot (if |
| supported) or plain directory (otherwise) and populated from this template tree. Ideally, the specified |
| template path refers to the root of a <literal>btrfs</literal> subvolume, in which case a simple copy-on-write |
| snapshot is taken, and populating the root directory is instant. If the specified template path does not refer |
| to the root of a <literal>btrfs</literal> subvolume (or not even to a <literal>btrfs</literal> file system at |
| all), the tree is copied (though possibly in a copy-on-write scheme — if the file system supports that), which |
| can be substantially more time-consuming. May not be specified together with <option>--image=</option> or |
| <option>--ephemeral</option>.</para> |
| |
| <para>Note that this switch leaves host name, machine ID and |
| all other settings that could identify the instance |
| unmodified.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-x</option></term> |
| <term><option>--ephemeral</option></term> |
| |
| <listitem><para>If specified, the container is run with a temporary snapshot of its file system that is removed |
| immediately when the container terminates. May not be specified together with |
| <option>--template=</option>.</para> |
| <para>Note that this switch leaves host name, machine ID and |
| all other settings that could identify the instance |
| unmodified.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-i</option></term> |
| <term><option>--image=</option></term> |
| |
| <listitem><para>Disk image to mount the root directory for the |
| container from. Takes a path to a regular file or to a block |
| device node. The file or block device must contain |
| either:</para> |
| |
| <itemizedlist> |
| <listitem><para>An MBR partition table with a single |
| partition of type 0x83 that is marked |
| bootable.</para></listitem> |
| |
| <listitem><para>A GUID partition table (GPT) with a single |
| partition of type |
| 0fc63daf-8483-4772-8e79-3d69d8477de4.</para></listitem> |
| |
| <listitem><para>A GUID partition table (GPT) with a marked |
| root partition which is mounted as the root directory of the |
| container. Optionally, GPT images may contain a home and/or |
| a server data partition which are mounted to the appropriate |
| places in the container. All these partitions must be |
| identified by the partition types defined by the <ulink |
| url="https://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/">Discoverable |
| Partitions Specification</ulink>.</para></listitem> |
| |
| <listitem><para>No partition table, and a single file system spanning the whole image.</para></listitem> |
| </itemizedlist> |
| |
| <para>On GPT images, if an EFI System Partition (ESP) is discovered, it is automatically mounted to |
| <filename>/efi</filename> (or <filename>/boot</filename> as fallback) in case a directory by this name exists |
| and is empty.</para> |
| |
| <para>Partitions encrypted with LUKS are automatically decrypted. Also, on GPT images dm-verity data integrity |
| hash partitions are set up if the root hash for them is specified using the <option>--root-hash=</option> |
| option.</para> |
| |
| <para>Any other partitions, such as foreign partitions or swap partitions are not mounted. May not be specified |
| together with <option>--directory=</option>, <option>--template=</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--root-hash=</option></term> |
| |
| <listitem><para>Takes a data integrity (dm-verity) root hash specified in hexadecimal. This option enables data |
| integrity checks using dm-verity, if the used image contains the appropriate integrity data (see above). The |
| specified hash must match the root hash of integrity data, and is usually at least 256 bits (and hence 64 |
| formatted hexadecimal characters) long (in case of SHA256 for example). If this option is not specified, but |
| the image file carries the <literal>user.verity.roothash</literal> extended file attribute (see <citerefentry |
| project='man-pages'><refentrytitle>xattr</refentrytitle><manvolnum>7</manvolnum></citerefentry>), then the root |
| hash is read from it, also as formatted hexadecimal characters. If the extended file attribute is not found (or |
| is not supported by the underlying file system), but a file with the <filename>.roothash</filename> suffix is |
| found next to the image file, bearing otherwise the same name, the root hash is read from it and automatically |
| used, also as formatted hexadecimal characters.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-a</option></term> |
| <term><option>--as-pid2</option></term> |
| |
| <listitem><para>Invoke the shell or specified program as process ID (PID) 2 instead of PID 1 (init). By |
| default, if neither this option nor <option>--boot</option> is used, the selected binary is run as process with |
| PID 1, a mode only suitable for programs that are aware of the special semantics that the process with PID 1 |
| has on UNIX. For example, it needs to reap all processes reparented to it, and should implement |
| <command>sysvinit</command> compatible signal handling (specifically: it needs to reboot on SIGINT, reexecute |
| on SIGTERM, reload configuration on SIGHUP, and so on). With <option>--as-pid2</option> a minimal stub init |
| process is run as PID 1 and the selected binary is executed as PID 2 (and hence does not need to implement any |
| special semantics). The stub init process will reap processes as necessary and react appropriately to |
| signals. It is recommended to use this mode to invoke arbitrary commands in containers, unless they have been |
| modified to run correctly as PID 1. Or in other words: this switch should be used for pretty much all commands, |
| except when the command refers to an init or shell implementation, as these are generally capable of running |
| correctly as PID 1. This option may not be combined with <option>--boot</option>.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-b</option></term> |
| <term><option>--boot</option></term> |
| |
| <listitem><para>Automatically search for an init binary and invoke it as PID 1, instead of a shell or a user |
| supplied program. If this option is used, arguments specified on the command line are used as arguments for the |
| init binary. This option may not be combined with <option>--as-pid2</option>.</para> |
| |
| <para>The following table explains the different modes of invocation and relationship to |
| <option>--as-pid2</option> (see above):</para> |
| |
| <table> |
| <title>Invocation Mode</title> |
| <tgroup cols='2' align='left' colsep='1' rowsep='1'> |
| <colspec colname="switch" /> |
| <colspec colname="explanation" /> |
| <thead> |
| <row> |
| <entry>Switch</entry> |
| <entry>Explanation</entry> |
| </row> |
| </thead> |
| <tbody> |
| <row> |
| <entry>Neither <option>--as-pid2</option> nor <option>--boot</option> specified</entry> |
| <entry>The passed parameters are interpreted as the command line, which is executed as PID 1 in the container.</entry> |
| </row> |
| |
| <row> |
| <entry><option>--as-pid2</option> specified</entry> |
| <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> |
| </row> |
| |
| <row> |
| <entry><option>--boot</option> specified</entry> |
| <entry>An init binary as automatically searched and run as PID 1 in the container. The passed parameters are used as invocation parameters for this process.</entry> |
| </row> |
| |
| </tbody> |
| </tgroup> |
| </table> |
| |
| <para>Note that <option>--boot</option> is the default mode of operation if the |
| <filename>systemd-nspawn@.service</filename> template unit file is used.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--chdir=</option></term> |
| |
| <listitem><para>Change to the specified working directory before invoking the process in the container. Expects |
| an absolute path in the container's file system namespace.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--pivot-root=</option></term> |
| |
| <listitem><para>Pivot the specified directory to <filename>/</filename> inside the container, and either unmount the |
| container's old root, or pivot it to another specified directory. Takes one of: a path argument — in which case the |
| specified path will be pivoted to <filename>/</filename> and the old root will be unmounted; or a colon-separated pair |
| of new root path and pivot destination for the old root. The new root path will be pivoted to <filename>/</filename>, |
| and the old <filename>/</filename> will be pivoted to the other directory. Both paths must be absolute, and are resolved |
| in the container's file system namespace.</para> |
| |
| <para>This is for containers which have several bootable directories in them; for example, several |
| <ulink url="https://ostree.readthedocs.io/en/latest/">OSTree</ulink> deployments. It emulates the behavior of |
| the boot loader and initial RAM disk which normally select which directory to mount as the root and start the |
| container's PID 1 in.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-u</option></term> |
| <term><option>--user=</option></term> |
| |
| <listitem><para>After transitioning into the container, change |
| to the specified user-defined in the container's user |
| database. Like all other systemd-nspawn features, this is not |
| a security feature and provides protection against accidental |
| destructive operations only.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-M</option></term> |
| <term><option>--machine=</option></term> |
| |
| <listitem><para>Sets the machine name for this container. This |
| name may be used to identify this container during its runtime |
| (for example in tools like |
| <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| and similar), and is used to initialize the container's |
| hostname (which the container can choose to override, |
| however). If not specified, the last component of the root |
| directory path of the container is used, possibly suffixed |
| with a random identifier in case <option>--ephemeral</option> |
| mode is selected. If the root directory selected is the host's |
| root directory the host's hostname is used as default |
| instead.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--uuid=</option></term> |
| |
| <listitem><para>Set the specified UUID for the container. The |
| init system will initialize |
| <filename>/etc/machine-id</filename> from this if this file is |
| not set yet. Note that this option takes effect only if |
| <filename>/etc/machine-id</filename> in the container is |
| unpopulated.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--slice=</option></term> |
| |
| <listitem><para>Make the container part of the specified |
| slice, instead of the default |
| <filename>machine.slice</filename>. This is only applies if |
| the machine is run in its own scope unit, i.e. if |
| <option>--keep-unit</option> is not used.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--property=</option></term> |
| |
| <listitem><para>Set a unit property on the scope unit to |
| register for the machine. This only applies if the machine is |
| run in its own scope unit, i.e. if |
| <option>--keep-unit</option> is not used. Takes unit property |
| assignments in the same format as <command>systemctl |
| set-property</command>. This is useful to set memory limits |
| and similar for machines.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--private-users=</option></term> |
| |
| <listitem><para>Controls user namespacing. If enabled, the container will run with its own private set of UNIX |
| user and group ids (UIDs and GIDs). This involves mapping the private UIDs/GIDs used in the container (starting |
| with the container's root user 0 and up) to a range of UIDs/GIDs on the host that are not used for other |
| purposes (usually in the range beyond the host's UID/GID 65536). The parameter may be specified as follows:</para> |
| |
| <orderedlist> |
| <listitem><para>If one or two colon-separated numbers are specified, user namespacing is turned on. The first |
| parameter specifies the first host UID/GID to assign to the container, the second parameter specifies the |
| number of host UIDs/GIDs to assign to the container. If the second parameter is omitted, 65536 UIDs/GIDs are |
| assigned.</para></listitem> |
| |
| <listitem><para>If the parameter is omitted, or true, user namespacing is turned on. The UID/GID range to |
| use is determined automatically from the file ownership of the root directory of the container's directory |
| tree. To use this option, make sure to prepare the directory tree in advance, and ensure that all files and |
| directories in it are owned by UIDs/GIDs in the range you'd like to use. Also, make sure that used file ACLs |
| exclusively reference UIDs/GIDs in the appropriate range. If this mode is used the number of UIDs/GIDs |
| assigned to the container for use is 65536, and the UID/GID of the root directory must be a multiple of |
| 65536.</para></listitem> |
| |
| <listitem><para>If the parameter is false, user namespacing is turned off. This is the default.</para> |
| </listitem> |
| |
| <listitem><para>The special value <literal>pick</literal> turns on user namespacing. In this case the UID/GID |
| range is automatically chosen. As first step, the file owner of the root directory of the container's |
| directory tree is read, and it is checked that it is currently not used by the system otherwise (in |
| particular, that no other container is using it). If this check is successful, the UID/GID range determined |
| this way is used, similar to the behavior if "yes" is specified. If the check is not successful (and thus |
| the UID/GID range indicated in the root directory's file owner is already used elsewhere) a new – currently |
| unused – UID/GID range of 65536 UIDs/GIDs is randomly chosen between the host UID/GIDs of 524288 and |
| 1878982656, always starting at a multiple of 65536. This setting implies |
| <option>--private-users-chown</option> (see below), which has the effect that the files and directories in |
| the container's directory tree will be owned by the appropriate users of the range picked. Using this option |
| makes user namespace behavior fully automatic. Note that the first invocation of a previously unused |
| container image might result in picking a new UID/GID range for it, and thus in the (possibly expensive) file |
| ownership adjustment operation. However, subsequent invocations of the container will be cheap (unless of |
| course the picked UID/GID range is assigned to a different use by then).</para></listitem> |
| </orderedlist> |
| |
| <para>It is recommended to assign at least 65536 UIDs/GIDs to each container, so that the usable UID/GID range in the |
| container covers 16 bit. For best security, do not assign overlapping UID/GID ranges to multiple containers. It is |
| hence a good idea to use the upper 16 bit of the host 32-bit UIDs/GIDs as container identifier, while the lower 16 |
| bit encode the container UID/GID used. This is in fact the behavior enforced by the |
| <option>--private-users=pick</option> option.</para> |
| |
| <para>When user namespaces are used, the GID range assigned to each container is always chosen identical to the |
| UID range.</para> |
| |
| <para>In most cases, using <option>--private-users=pick</option> is the recommended option as it enhances |
| container security massively and operates fully automatically in most cases.</para> |
| |
| <para>Note that the picked UID/GID range is not written to <filename>/etc/passwd</filename> or |
| <filename>/etc/group</filename>. In fact, the allocation of the range is not stored persistently anywhere, |
| except in the file ownership of the files and directories of the container.</para> |
| |
| <para>Note that when user namespacing is used file ownership on disk reflects this, and all of the container's |
| files and directories are owned by the container's effective user and group IDs. This means that copying files |
| from and to the container image requires correction of the numeric UID/GID values, according to the UID/GID |
| shift applied.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--private-users-chown</option></term> |
| |
| <listitem><para>If specified, all files and directories in the container's directory tree will adjusted so that |
| they are owned to the appropriate UIDs/GIDs selected for the container (see above). This operation is |
| potentially expensive, as it involves descending and iterating through the full directory tree of the |
| container. Besides actual file ownership, file ACLs are adjusted as well.</para> |
| |
| <para>This option is implied if <option>--private-users=pick</option> is used. This option has no effect if |
| user namespacing is not used.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-U</option></term> |
| |
| <listitem><para>If the kernel supports the user namespaces feature, equivalent to |
| <option>--private-users=pick --private-users-chown</option>, otherwise equivalent to |
| <option>--private-users=no</option>.</para> |
| |
| <para>Note that <option>-U</option> is the default if the |
| <filename>systemd-nspawn@.service</filename> template unit file is used.</para> |
| |
| <para>Note: it is possible to undo the effect of <option>--private-users-chown</option> (or |
| <option>-U</option>) on the file system by redoing the operation with the first UID of 0:</para> |
| |
| <programlisting>systemd-nspawn … --private-users=0 --private-users-chown</programlisting> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--private-network</option></term> |
| |
| <listitem><para>Disconnect networking of the container from |
| the host. This makes all network interfaces unavailable in the |
| container, with the exception of the loopback device and those |
| specified with <option>--network-interface=</option> and |
| configured with <option>--network-veth</option>. If this |
| option is specified, the CAP_NET_ADMIN capability will be |
| added to the set of capabilities the container retains. The |
| latter may be disabled by using |
| <option>--drop-capability=</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--network-interface=</option></term> |
| |
| <listitem><para>Assign the specified network interface to the |
| container. This will remove the specified interface from the |
| calling namespace and place it in the container. When the |
| container terminates, it is moved back to the host namespace. |
| Note that <option>--network-interface=</option> implies |
| <option>--private-network</option>. This option may be used |
| more than once to add multiple network interfaces to the |
| container.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--network-macvlan=</option></term> |
| |
| <listitem><para>Create a <literal>macvlan</literal> interface |
| of the specified Ethernet network interface and add it to the |
| container. A <literal>macvlan</literal> interface is a virtual |
| interface that adds a second MAC address to an existing |
| physical Ethernet link. The interface in the container will be |
| named after the interface on the host, prefixed with |
| <literal>mv-</literal>. Note that |
| <option>--network-macvlan=</option> implies |
| <option>--private-network</option>. This option may be used |
| more than once to add multiple network interfaces to the |
| container.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--network-ipvlan=</option></term> |
| |
| <listitem><para>Create an <literal>ipvlan</literal> interface |
| of the specified Ethernet network interface and add it to the |
| container. An <literal>ipvlan</literal> interface is a virtual |
| interface, similar to a <literal>macvlan</literal> interface, |
| which uses the same MAC address as the underlying interface. |
| The interface in the container will be named after the |
| interface on the host, prefixed with <literal>iv-</literal>. |
| Note that <option>--network-ipvlan=</option> implies |
| <option>--private-network</option>. This option may be used |
| more than once to add multiple network interfaces to the |
| container.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-n</option></term> |
| <term><option>--network-veth</option></term> |
| |
| <listitem><para>Create a virtual Ethernet link (<literal>veth</literal>) between host and container. The host |
| side of the Ethernet link will be available as a network interface named after the container's name (as |
| specified with <option>--machine=</option>), prefixed with <literal>ve-</literal>. The container side of the |
| Ethernet link will be named <literal>host0</literal>. The <option>--network-veth</option> option implies |
| <option>--private-network</option>.</para> |
| |
| <para>Note that |
| <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| includes by default a network file <filename>/usr/lib/systemd/network/80-container-ve.network</filename> |
| matching the host-side interfaces created this way, which contains settings to enable automatic address |
| provisioning on the created virtual link via DHCP, as well as automatic IP routing onto the host's external |
| network interfaces. It also contains <filename>/usr/lib/systemd/network/80-container-host0.network</filename> |
| matching the container-side interface created this way, containing settings to enable client side address |
| assignment via DHCP. In case <filename>systemd-networkd</filename> is running on both the host and inside the |
| container, automatic IP communication from the container to the host is thus available, with further |
| connectivity to the external network.</para> |
| |
| <para>Note that <option>--network-veth</option> is the default if the |
| <filename>systemd-nspawn@.service</filename> template unit file is used.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--network-veth-extra=</option></term> |
| |
| <listitem><para>Adds an additional virtual Ethernet link |
| between host and container. Takes a colon-separated pair of |
| host interface name and container interface name. The latter |
| may be omitted in which case the container and host sides will |
| be assigned the same name. This switch is independent of |
| <option>--network-veth</option>, and — in contrast — may be |
| used multiple times, and allows configuration of the network |
| interface names. Note that <option>--network-bridge=</option> |
| has no effect on interfaces created with |
| <option>--network-veth-extra=</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--network-bridge=</option></term> |
| |
| <listitem><para>Adds the host side of the Ethernet link created with <option>--network-veth</option> to the |
| specified Ethernet bridge interface. Expects a valid network interface name of a bridge device as |
| argument. Note that <option>--network-bridge=</option> implies <option>--network-veth</option>. If this option |
| is used, the host side of the Ethernet link will use the <literal>vb-</literal> prefix instead of |
| <literal>ve-</literal>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--network-zone=</option></term> |
| |
| <listitem><para>Creates a virtual Ethernet link (<literal>veth</literal>) to the container and adds it to an |
| automatically managed Ethernet bridge interface. The bridge interface is named after the passed argument, |
| prefixed with <literal>vz-</literal>. The bridge interface is automatically created when the first container |
| configured for its name is started, and is automatically removed when the last container configured for its |
| name exits. Hence, each bridge interface configured this way exists only as long as there's at least one |
| container referencing it running. This option is very similar to <option>--network-bridge=</option>, besides |
| this automatic creation/removal of the bridge device.</para> |
| |
| <para>This setting makes it easy to place multiple related containers on a common, virtual Ethernet-based |
| broadcast domain, here called a "zone". Each container may only be part of one zone, but each zone may contain |
| any number of containers. Each zone is referenced by its name. Names may be chosen freely (as long as they form |
| valid network interface names when prefixed with <literal>vz-</literal>), and it is sufficient to pass the same |
| name to the <option>--network-zones=</option> switch of the various concurrently running containers to join |
| them in one zone.</para> |
| |
| <para>Note that |
| <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| includes by default a network file <filename>/usr/lib/systemd/network/80-container-vz.network</filename> |
| matching the bridge interfaces created this way, which contains settings to enable automatic address |
| provisioning on the created virtual network via DHCP, as well as automatic IP routing onto the host's external |
| network interfaces. Using <option>--network-zone=</option> is hence in most cases fully automatic and |
| sufficient to connect multiple local containers in a joined broadcast domain to the host, with further |
| connectivity to the external network.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-p</option></term> |
| <term><option>--port=</option></term> |
| |
| <listitem><para>If private networking is enabled, maps an IP |
| port on the host onto an IP port on the container. Takes a |
| protocol specifier (either <literal>tcp</literal> or |
| <literal>udp</literal>), separated by a colon from a host port |
| number in the range 1 to 65535, separated by a colon from a |
| container port number in the range from 1 to 65535. The |
| protocol specifier and its separating colon may be omitted, in |
| which case <literal>tcp</literal> is assumed. The container |
| port number and its colon may be omitted, in which case the |
| same port as the host port is implied. This option is only |
| supported if private networking is used, such as with |
| <option>--network-veth</option>, <option>--network-zone=</option> |
| <option>--network-bridge=</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-Z</option></term> |
| <term><option>--selinux-context=</option></term> |
| |
| <listitem><para>Sets the SELinux security context to be used |
| to label processes in the container.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-L</option></term> |
| <term><option>--selinux-apifs-context=</option></term> |
| |
| <listitem><para>Sets the SELinux security context to be used |
| to label files in the virtual API file systems in the |
| container.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--capability=</option></term> |
| |
| <listitem><para>List one or more additional capabilities to |
| grant the container. Takes a comma-separated list of |
| capability names, see |
| <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
| for more information. Note that the following capabilities |
| will be granted in any way: CAP_CHOWN, CAP_DAC_OVERRIDE, |
| CAP_DAC_READ_SEARCH, CAP_FOWNER, CAP_FSETID, CAP_IPC_OWNER, |
| CAP_KILL, CAP_LEASE, CAP_LINUX_IMMUTABLE, |
| CAP_NET_BIND_SERVICE, CAP_NET_BROADCAST, CAP_NET_RAW, |
| CAP_SETGID, CAP_SETFCAP, CAP_SETPCAP, CAP_SETUID, |
| CAP_SYS_ADMIN, CAP_SYS_CHROOT, CAP_SYS_NICE, CAP_SYS_PTRACE, |
| CAP_SYS_TTY_CONFIG, CAP_SYS_RESOURCE, CAP_SYS_BOOT, |
| CAP_AUDIT_WRITE, CAP_AUDIT_CONTROL. Also CAP_NET_ADMIN is |
| retained if <option>--private-network</option> is specified. |
| If the special value <literal>all</literal> is passed, all |
| capabilities are retained.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--drop-capability=</option></term> |
| |
| <listitem><para>Specify one or more additional capabilities to |
| drop for the container. This allows running the container with |
| fewer capabilities than the default (see |
| above).</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--kill-signal=</option></term> |
| |
| <listitem><para>Specify the process signal to send to the |
| container's PID 1 when nspawn itself receives SIGTERM, in |
| order to trigger an orderly shutdown of the |
| container. Defaults to SIGRTMIN+3 if <option>--boot</option> |
| is used (on systemd-compatible init systems SIGRTMIN+3 |
| triggers an orderly shutdown). For a list of valid signals, see |
| <citerefentry project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--link-journal=</option></term> |
| |
| <listitem><para>Control whether the container's journal shall |
| be made visible to the host system. If enabled, allows viewing |
| the container's journal files from the host (but not vice |
| versa). Takes one of <literal>no</literal>, |
| <literal>host</literal>, <literal>try-host</literal>, |
| <literal>guest</literal>, <literal>try-guest</literal>, |
| <literal>auto</literal>. If <literal>no</literal>, the journal |
| is not linked. If <literal>host</literal>, the journal files |
| are stored on the host file system (beneath |
| <filename>/var/log/journal/<replaceable>machine-id</replaceable></filename>) |
| and the subdirectory is bind-mounted into the container at the |
| same location. If <literal>guest</literal>, the journal files |
| are stored on the guest file system (beneath |
| <filename>/var/log/journal/<replaceable>machine-id</replaceable></filename>) |
| and the subdirectory is symlinked into the host at the same |
| location. <literal>try-host</literal> and |
| <literal>try-guest</literal> do the same but do not fail if |
| the host does not have persistent journaling enabled. If |
| <literal>auto</literal> (the default), and the right |
| subdirectory of <filename>/var/log/journal</filename> exists, |
| it will be bind mounted into the container. If the |
| subdirectory does not exist, no linking is performed. |
| Effectively, booting a container once with |
| <literal>guest</literal> or <literal>host</literal> will link |
| the journal persistently if further on the default of |
| <literal>auto</literal> is used.</para> |
| |
| <para>Note that <option>--link-journal=try-guest</option> is the default if the |
| <filename>systemd-nspawn@.service</filename> template unit file is used.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-j</option></term> |
| |
| <listitem><para>Equivalent to |
| <option>--link-journal=try-guest</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--read-only</option></term> |
| |
| <listitem><para>Mount the root file system read-only for the |
| container.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--bind=</option></term> |
| <term><option>--bind-ro=</option></term> |
| |
| <listitem><para>Bind mount a file or directory from the host into the container. Takes one of: a path |
| argument — in which case the specified path will be mounted from the host to the same path in the container, or |
| a colon-separated pair of paths — in which case the first specified path is the source in the host, and the |
| second path is the destination in the container, or a colon-separated triple of source path, destination path |
| and mount options. The source path may optionally be prefixed with a <literal>+</literal> character. If so, the |
| source path is taken relative to the image's root directory. This permits setting up bind mounts within the |
| container image. The source path may be specified as empty string, in which case a temporary directory below |
| the host's <filename>/var/tmp</filename> directory is used. It is automatically removed when the container is |
| shut down. Mount options are comma-separated and currently, only <option>rbind</option> and |
| <option>norbind</option> are allowed, controlling whether to create a recursive or a regular bind |
| mount. Defaults to "rbind". Backslash escapes are interpreted, so <literal>\:</literal> may be used to embed |
| colons in either path. This option may be specified multiple times for creating multiple independent bind |
| mount points. The <option>--bind-ro=</option> option creates read-only bind mounts.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--tmpfs=</option></term> |
| |
| <listitem><para>Mount a tmpfs file system into the container. |
| Takes a single absolute path argument that specifies where to |
| mount the tmpfs instance to (in which case the directory |
| access mode will be chosen as 0755, owned by root/root), or |
| optionally a colon-separated pair of path and mount option |
| string that is used for mounting (in which case the kernel |
| default for access mode and owner will be chosen, unless |
| otherwise specified). This option is particularly useful for |
| mounting directories such as <filename>/var</filename> as |
| tmpfs, to allow state-less systems, in particular when |
| combined with <option>--read-only</option>. |
| Backslash escapes are interpreted in the path, so |
| <literal>\:</literal> may be used to embed colons in the path. |
| </para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--overlay=</option></term> |
| <term><option>--overlay-ro=</option></term> |
| |
| <listitem><para>Combine multiple directory trees into one |
| overlay file system and mount it into the container. Takes a |
| list of colon-separated paths to the directory trees to |
| combine and the destination mount point.</para> |
| |
| <para>Backslash escapes are interpreted in the paths, so |
| <literal>\:</literal> may be used to embed colons in the paths. |
| </para> |
| |
| <para>If three or more paths are specified, then the last |
| specified path is the destination mount point in the |
| container, all paths specified before refer to directory trees |
| on the host and are combined in the specified order into one |
| overlay file system. The left-most path is hence the lowest |
| directory tree, the second-to-last path the highest directory |
| tree in the stacking order. If <option>--overlay-ro=</option> |
| is used instead of <option>--overlay=</option>, a read-only |
| overlay file system is created. If a writable overlay file |
| system is created, all changes made to it are written to the |
| highest directory tree in the stacking order, i.e. the |
| second-to-last specified.</para> |
| |
| <para>If only two paths are specified, then the second |
| specified path is used both as the top-level directory tree in |
| the stacking order as seen from the host, as well as the mount |
| point for the overlay file system in the container. At least |
| two paths have to be specified.</para> |
| |
| <para>The source paths may optionally be prefixed with <literal>+</literal> character. If so they are taken |
| relative to the image's root directory. The uppermost source path may also be specified as empty string, in |
| which case a temporary directory below the host's <filename>/var/tmp</filename> is used. The directory is |
| removed automatically when the container is shut down. This behaviour is useful in order to make read-only |
| container directories writable while the container is running. For example, use the |
| <literal>--overlay=+/var::/var</literal> option in order to automatically overlay a writable temporary |
| directory on a read-only <filename>/var</filename> directory.</para> |
| |
| <para>For details about overlay file systems, see <ulink |
| url="https://www.kernel.org/doc/Documentation/filesystems/overlayfs.txt">overlayfs.txt</ulink>. Note |
| that the semantics of overlay file systems are substantially |
| different from normal file systems, in particular regarding |
| reported device and inode information. Device and inode |
| information may change for a file while it is being written |
| to, and processes might see out-of-date versions of files at |
| times. Note that this switch automatically derives the |
| <literal>workdir=</literal> mount option for the overlay file |
| system from the top-level directory tree, making it a sibling |
| of it. It is hence essential that the top-level directory tree |
| is not a mount point itself (since the working directory must |
| be on the same file system as the top-most directory |
| tree). Also note that the <literal>lowerdir=</literal> mount |
| option receives the paths to stack in the opposite order of |
| this switch.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-E <replaceable>NAME</replaceable>=<replaceable>VALUE</replaceable></option></term> |
| <term><option>--setenv=<replaceable>NAME</replaceable>=<replaceable>VALUE</replaceable></option></term> |
| |
| <listitem><para>Specifies an environment variable assignment |
| to pass to the init process in the container, in the format |
| <literal>NAME=VALUE</literal>. This may be used to override |
| the default variables or to set additional variables. This |
| parameter may be used more than once.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--register=</option></term> |
| |
| <listitem><para>Controls whether the container is registered |
| with |
| <citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>8</manvolnum></citerefentry>. |
| Takes a boolean argument, which defaults to <literal>yes</literal>. |
| This option should be enabled when the container runs a full |
| Operating System (more specifically: an init system), and is |
| useful to ensure that the container is accessible via |
| <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| and shown by tools such as |
| <citerefentry project='man-pages'><refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum></citerefentry>. |
| If the container does not run an init system, it is |
| recommended to set this option to <literal>no</literal>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--keep-unit</option></term> |
| |
| <listitem><para>Instead of creating a transient scope unit to |
| run the container in, simply register the service or scope |
| unit <command>systemd-nspawn</command> has been invoked in |
| with |
| <citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>8</manvolnum></citerefentry>. |
| This has no effect if <option>--register=no</option> is used. |
| This switch should be used if |
| <command>systemd-nspawn</command> is invoked from within a |
| service unit, and the service unit's sole purpose is to run a |
| single <command>systemd-nspawn</command> container. This |
| option is not available if run from a user |
| session.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--personality=</option></term> |
| |
| <listitem><para>Control the architecture ("personality") |
| reported by |
| <citerefentry project='man-pages'><refentrytitle>uname</refentrytitle><manvolnum>2</manvolnum></citerefentry> |
| in the container. Currently, only <literal>x86</literal> and |
| <literal>x86-64</literal> are supported. This is useful when |
| running a 32-bit container on a 64-bit host. If this setting |
| is not used, the personality reported in the container is the |
| same as the one reported on the host.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-q</option></term> |
| <term><option>--quiet</option></term> |
| |
| <listitem><para>Turns off any status output by the tool |
| itself. When this switch is used, the only output from nspawn |
| will be the console output of the container OS |
| itself.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--volatile</option></term> |
| <term><option>--volatile=</option><replaceable>MODE</replaceable></term> |
| |
| <listitem><para>Boots the container in volatile mode. When no |
| mode parameter is passed or when mode is specified as |
| <option>yes</option>, full volatile mode is enabled. This |
| means the root directory is mounted as a mostly unpopulated |
| <literal>tmpfs</literal> instance, and |
| <filename>/usr</filename> from the OS tree is mounted into it |
| in read-only mode (the system thus starts up with read-only OS |
| image, but pristine state and configuration, any changes |
| are lost on shutdown). When the mode parameter |
| is specified as <option>state</option>, the OS tree is |
| mounted read-only, but <filename>/var</filename> is mounted as |
| a <literal>tmpfs</literal> instance into it (the system thus |
| starts up with read-only OS resources and configuration, but |
| pristine state, and any changes to the latter are lost on |
| shutdown). When the mode parameter is specified as |
| <option>no</option> (the default), the whole OS tree is made |
| available writable.</para> |
| |
| <para>This option provides similar functionality for containers as the <literal>systemd.volatile=</literal> |
| kernel command line switch provides for host systems. See |
| <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry> for |
| details.</para> |
| |
| <para>Note that enabling this setting will only work correctly with operating systems in the container that can |
| boot up with only <filename>/usr</filename> mounted, and are able to automatically populate |
| <filename>/var</filename>, and also <filename>/etc</filename> in case of |
| <literal>--volatile=yes</literal>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--settings=</option><replaceable>MODE</replaceable></term> |
| |
| <listitem><para>Controls whether |
| <command>systemd-nspawn</command> shall search for and use |
| additional per-container settings from |
| <filename>.nspawn</filename> files. Takes a boolean or the |
| special values <option>override</option> or |
| <option>trusted</option>.</para> |
| |
| <para>If enabled (the default), a settings file named after the |
| machine (as specified with the <option>--machine=</option> |
| setting, or derived from the directory or image file name) |
| with the suffix <filename>.nspawn</filename> is searched in |
| <filename>/etc/systemd/nspawn/</filename> and |
| <filename>/run/systemd/nspawn/</filename>. If it is found |
| there, its settings are read and used. If it is not found |
| there, it is subsequently searched in the same directory as the |
| image file or in the immediate parent of the root directory of |
| the container. In this case, if the file is found, its settings |
| will be also read and used, but potentially unsafe settings |
| are ignored. Note that in both these cases, settings on the |
| command line take precedence over the corresponding settings |
| from loaded <filename>.nspawn</filename> files, if both are |
| specified. Unsafe settings are considered all settings that |
| elevate the container's privileges or grant access to |
| additional resources such as files or directories of the |
| host. For details about the format and contents of |
| <filename>.nspawn</filename> files, consult |
| <citerefentry><refentrytitle>systemd.nspawn</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> |
| |
| <para>If this option is set to <option>override</option>, the |
| file is searched, read and used the same way, however, the order of |
| precedence is reversed: settings read from the |
| <filename>.nspawn</filename> file will take precedence over |
| the corresponding command line options, if both are |
| specified.</para> |
| |
| <para>If this option is set to <option>trusted</option>, the |
| file is searched, read and used the same way, but regardless |
| of being found in <filename>/etc/systemd/nspawn/</filename>, |
| <filename>/run/systemd/nspawn/</filename> or next to the image |
| file or container root directory, all settings will take |
| effect, however, command line arguments still take precedence |
| over corresponding settings.</para> |
| |
| <para>If disabled, no <filename>.nspawn</filename> file is read |
| and no settings except the ones on the command line are in |
| effect.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--notify-ready=</option></term> |
| |
| <listitem><para>Configures support for notifications from the container's init process. |
| <option>--notify-ready=</option> takes a boolean (<option>no</option> and <option>yes</option>). |
| With option <option>no</option> systemd-nspawn notifies systemd |
| with a <literal>READY=1</literal> message when the init process is created. |
| With option <option>yes</option> systemd-nspawn waits for the |
| <literal>READY=1</literal> message from the init process in the container |
| before sending its own to systemd. For more details about notifications |
| see <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>).</para></listitem> |
| </varlistentry> |
| |
| <xi:include href="standard-options.xml" xpointer="help" /> |
| <xi:include href="standard-options.xml" xpointer="version" /> |
| </variablelist> |
| |
| </refsect1> |
| |
| <refsect1> |
| <title>Examples</title> |
| |
| <example> |
| <title>Download a Fedora image and start a shell in it</title> |
| |
| <programlisting># machinectl pull-raw --verify=no \ |
| https://download.fedoraproject.org/pub/fedora/linux/releases/25/CloudImages/x86_64/images/Fedora-Cloud-Base-25-1.3.x86_64.raw.xz |
| # systemd-nspawn -M Fedora-Cloud-Base-25-1.3.x86_64.raw</programlisting> |
| |
| <para>This downloads an image using |
| <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| and opens a shell in it.</para> |
| </example> |
| |
| <example> |
| <title>Build and boot a minimal Fedora distribution in a container</title> |
| |
| <programlisting># dnf -y --releasever=25 --installroot=/srv/mycontainer \ |
| --disablerepo='*' --enablerepo=fedora --enablerepo=updates install \ |
| systemd passwd dnf fedora-release vim-minimal |
| # systemd-nspawn -bD /srv/mycontainer</programlisting> |
| |
| <para>This installs a minimal Fedora distribution into the |
| directory <filename noindex='true'>/srv/mycontainer/</filename> |
| and then boots an OS in a namespace container in it.</para> |
| </example> |
| |
| <example> |
| <title>Spawn a shell in a container of a minimal Debian unstable distribution</title> |
| |
| <programlisting># debootstrap --arch=amd64 unstable ~/debian-tree/ |
| # systemd-nspawn -D ~/debian-tree/</programlisting> |
| |
| <para>This installs a minimal Debian unstable distribution into |
| the directory <filename>~/debian-tree/</filename> and then |
| spawns a shell in a namespace container in it.</para> |
| </example> |
| |
| <example> |
| <title>Boot a minimal Arch Linux distribution in a container</title> |
| |
| <programlisting># pacstrap -c -d ~/arch-tree/ base |
| # systemd-nspawn -bD ~/arch-tree/</programlisting> |
| |
| <para>This installs a minimal Arch Linux distribution into the |
| directory <filename>~/arch-tree/</filename> and then boots an OS |
| in a namespace container in it.</para> |
| </example> |
| |
| <example> |
| <title>Boot into an ephemeral snapshot of the host system</title> |
| |
| <programlisting># systemd-nspawn -D / -xb</programlisting> |
| |
| <para>This runs a copy of the host system in a snapshot which is removed immediately when the container |
| exits. All file system changes made during runtime will be lost on shutdown, hence.</para> |
| </example> |
| |
| <example> |
| <title>Run a container with SELinux sandbox security contexts</title> |
| |
| <programlisting># chcon system_u:object_r:svirt_sandbox_file_t:s0:c0,c1 -R /srv/container |
| # 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> |
| </example> |
| |
| <example> |
| <title>Run a container with an OSTree deployment</title> |
| |
| <programlisting># systemd-nspawn -b -i ~/image.raw \ |
| --pivot-root=/ostree/deploy/$OS/deploy/$CHECKSUM:/sysroot \ |
| --bind=+/sysroot/ostree/deploy/$OS/var:/var</programlisting> |
| </example> |
| </refsect1> |
| |
| <refsect1> |
| <title>Exit status</title> |
| |
| <para>The exit code of the program executed in the container is |
| returned.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>See Also</title> |
| <para> |
| <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemd.nspawn</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| <citerefentry project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| <citerefentry project='mankier'><refentrytitle>dnf</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
| <citerefentry project='die-net'><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
| <citerefentry project='archlinux'><refentrytitle>pacman</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| <citerefentry project='man-pages'><refentrytitle>btrfs</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| </para> |
| </refsect1> |
| |
| </refentry> |