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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
-<!ENTITY fedora_latest_version "28">
-<!ENTITY fedora_cloud_release "1.1">
+<!ENTITY fedora_latest_version "30">
+<!ENTITY fedora_cloud_release "1.2">
]>
<!-- SPDX-License-Identifier: LGPL-2.1+ -->
<para>The following options are understood:</para>
<variablelist>
+
+ <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>--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>
+
+ </variablelist>
+
+ <refsect2>
+ <title>Image Options</title>
+
+ <variablelist>
+
<varlistentry>
<term><option>-D</option></term>
<term><option>--directory=</option></term>
from the OCI runtime JSON data (but data passed on the command line takes precedence).</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><option>--read-only</option></term>
+
+ <listitem><para>Mount the container's root file system (and any other file systems container in the container
+ image) read-only. This has no effect on additional mounts made with <option>--bind=</option>,
+ <option>--tmpfs=</option> and similar options. This mode is implied if the container image file or directory is
+ marked read-only itself. It is also implied if <option>--volatile=</option> is used. In this case the container
+ image on disk is strictly read-only, while changes are permitted but kept non-persistently in memory only. For
+ further details, see below.</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
+ writable <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>overlay</option> the read-only root file system is combined with a writable
+ <filename>tmpfs</filename> instance through <literal>overlayfs</literal>, so that it appears at it normally
+ would, but any changes are applied to the temporary file system only and lost when the container is
+ terminated. When the mode parameter is specified as <option>no</option> (the default), the whole OS tree is
+ made available writable (unless <option>--read-only</option> is specified, see above).</para>
+
+ <para>Note that if one of the volatile modes is chosen, its effect is limited to the root file system (or
+ <filename>/var/</filename> in case of <option>state</option>), and any other mounts placed in the hierarchy are
+ unaffected — regardless if they are established automatically (e.g. the EFI system partition that might be
+ mounted to <filename>/efi/</filename> or <filename>/boot/</filename>) or explicitly (e.g. through an additional
+ command line option such as <option>--bind=</option>, see below). This means, even if
+ <option>--volatile=overlay</option> is used changes to <filename>/efi/</filename> or
+ <filename>/boot/</filename> are prohibited in case such a partition exists in the container image operated on,
+ and even if <option>--volatile=state</option> is used the hypothetical file <filename>/etc/foobar</filename> is
+ potentially writable if <option>--bind=/etc/foobar</option> if used to mount it from outside the read-only
+ container <filename>/etc</filename> directory.</para>
+
+ <para>The <option>--ephemeral</option> option is closely related to this setting, and provides similar
+ behaviour by making a temporary, ephemeral copy of the whole OS image and executing that. For further details,
+ see above.</para>
+
+ <para>The <option>--tmpfs=</option> and <option>--overlay=</option> options provide similar functionality, but
+ for specific sub-directories of the OS image only. For details, see below.</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 setting this option to <option>yes</option> or <option>state</option> 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 <filename>/etc/</filename> in case of <literal>--volatile=yes</literal>). Specifically, this
+ means that operating systems that follow the historic split of <filename>/bin/</filename> and
+ <filename>/lib/</filename> (and related directories) from <filename>/usr/</filename> (i.e. where the
+ former are not symlinks into the latter) are not supported by <literal>--volatile=yes</literal> as
+ container payload. The <option>overlay</option> option does not require any particular preparations
+ in the OS, but do note that <literal>overlayfs</literal> behaviour differs from regular file systems
+ in a number of ways, and hence compatibility is limited.</para></listitem>
+ </varlistentry>
+
<varlistentry>
<term><option>--root-hash=</option></term>
used, also as formatted hexadecimal characters.</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>
+ </variablelist>
+
+ </refsect2><refsect2>
+ <title>Execution Options</title>
+
+ <variablelist>
<varlistentry>
<term><option>-a</option></term>
<term><option>--as-pid2</option></term>
</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>
+ <term><option>-E <replaceable>NAME</replaceable>=<replaceable>VALUE</replaceable></option></term>
+ <term><option>--setenv=<replaceable>NAME</replaceable>=<replaceable>VALUE</replaceable></option></term>
- <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>
+ <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>
destructive operations only.</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
+ <constant>SIGTERM</constant>, in order to trigger an orderly shutdown of the container. Defaults to
+ <constant>SIGRTMIN+3</constant> if <option>--boot</option> is used (on systemd-compatible init systems
+ <constant>SIGRTMIN+3</constant> triggers an orderly shutdown). If <option>--boot</option> is not used and this
+ option is not specified the container's processes are terminated abruptly via <constant>SIGKILL</constant>. For
+ a list of valid signals, see <citerefentry
+ project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</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>
+ </variablelist>
+
+ </refsect2><refsect2>
+ <title>System Identity Options</title>
+
+ <variablelist>
<varlistentry>
<term><option>-M</option></term>
<term><option>--machine=</option></term>
<filename>/etc/machine-id</filename> in the container is
unpopulated.</para></listitem>
</varlistentry>
+ </variablelist>
+ </refsect2><refsect2>
+ <title>Property Options</title>
+
+ <variablelist>
<varlistentry>
<term><option>-S</option></term>
<term><option>--slice=</option></term>
</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: a system and service manager as PID 1), 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 a service manager, 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 use the service or
+ scope unit <command>systemd-nspawn</command> has been invoked in. If <option>--register=yes</option> is set
+ this unit is registered with
+ <citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>8</manvolnum></citerefentry>. 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>
+ <para>Note that passing <option>--keep-unit</option> disables the effect of <option>--slice=</option> and
+ <option>--property=</option>. Use <option>--keep-unit</option> and <option>--register=no</option> in
+ combination to disable any kind of unit allocation or registration with
+ <command>systemd-machined</command>.</para></listitem>
+ </varlistentry>
+ </variablelist>
+
+ </refsect2><refsect2>
+ <title>User Namespacing Options</title>
+
+ <variablelist>
<varlistentry>
<term><option>--private-users=</option></term>
<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>
+ <listitem><para>If specified, all files and directories in the container's directory tree will be
+ adjusted so that they are owned by the appropriate UIDs/GIDs selected for the container (see above).
+ This operation is potentially expensive, as it involves 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>
</listitem>
</varlistentry>
+ </variablelist>
+
+ </refsect2><refsect2>
+ <title>Networking Options</title>
+
+ <variablelist>
+
<varlistentry>
<term><option>--private-network</option></term>
</para></listitem>
</varlistentry>
- <varlistentry>
- <term><option>--network-namespace-path=</option></term>
-
- <listitem><para>Takes the path to a file representing a kernel
- network namespace that the container shall run in. The specified path
- should refer to a (possibly bind-mounted) network namespace file, as
- exposed by the kernel below <filename>/proc/$PID/ns/net</filename>.
- This makes the container enter the given network namespace. One of the
- typical use cases is to give a network namespace under
- <filename>/run/netns</filename> created by <citerefentry
- project='man-pages'><refentrytitle>ip-netns</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
- for example, <option>--network-namespace-path=/run/netns/foo</option>.
- Note that this option cannot be used together with other
- network-related options, such as <option>--private-network</option>
- or <option>--network-interface=</option>.</para></listitem>
- </varlistentry>
-
<varlistentry>
<term><option>--network-interface=</option></term>
</varlistentry>
<varlistentry>
- <term><option>-p</option></term>
- <term><option>--port=</option></term>
+ <term><option>--network-namespace-path=</option></term>
- <listitem><para>If private networking is enabled, maps an IP
- port on the host onto an IP port on the container. Takes a
- protocol specifier (either <literal>tcp</literal> or
- <literal>udp</literal>), separated by a colon from a host port
- number in the range 1 to 65535, separated by a colon from a
- container port number in the range from 1 to 65535. The
- protocol specifier and its separating colon may be omitted, in
- which case <literal>tcp</literal> is assumed. The container
- port number and its colon may be omitted, in which case the
- same port as the host port is implied. This option is only
- supported if private networking is used, such as with
- <option>--network-veth</option>, <option>--network-zone=</option>
- <option>--network-bridge=</option>.</para></listitem>
+ <listitem><para>Takes the path to a file representing a kernel
+ network namespace that the container shall run in. The specified path
+ should refer to a (possibly bind-mounted) network namespace file, as
+ exposed by the kernel below <filename>/proc/$PID/ns/net</filename>.
+ This makes the container enter the given network namespace. One of the
+ typical use cases is to give a network namespace under
+ <filename>/run/netns</filename> created by <citerefentry
+ project='man-pages'><refentrytitle>ip-netns</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ for example, <option>--network-namespace-path=/run/netns/foo</option>.
+ Note that this option cannot be used together with other
+ network-related options, such as <option>--private-network</option>
+ or <option>--network-interface=</option>.</para></listitem>
</varlistentry>
<varlistentry>
- <term><option>-Z</option></term>
- <term><option>--selinux-context=</option></term>
+ <term><option>-p</option></term>
+ <term><option>--port=</option></term>
- <listitem><para>Sets the SELinux security context to be used
- to label processes in the container.</para>
- </listitem>
+ <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>
+ </variablelist>
- <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>
+ </refsect2><refsect2>
+ <title>Security Options</title>
+ <variablelist>
<varlistentry>
<term><option>--capability=</option></term>
capabilities are passed using the <command>--capabilities=</command>.</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>
+ </variablelist>
+
+ </refsect2><refsect2>
+ <title>Resource Options</title>
+
+ <variablelist>
+
<varlistentry>
<term><option>--rlimit=</option></term>
</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
- <constant>SIGTERM</constant>, in order to trigger an orderly shutdown of the container. Defaults to
- <constant>SIGRTMIN+3</constant> if <option>--boot</option> is used (on systemd-compatible init systems
- <constant>SIGRTMIN+3</constant> triggers an orderly shutdown). If <option>--boot</option> is not used and this
- option is not specified the container's processes are terminated abruptly via <constant>SIGKILL</constant>. 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>
+ <term><option>--personality=</option></term>
- <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>
+ <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>
+ </variablelist>
- <varlistentry>
- <term><option>-j</option></term>
-
- <listitem><para>Equivalent to
- <option>--link-journal=try-guest</option>.</para></listitem>
- </varlistentry>
+ </refsect2><refsect2>
+ <title>Integration Options</title>
+ <variablelist>
<varlistentry>
<term><option>--resolv-conf=</option></term>
</varlistentry>
<varlistentry>
- <term><option>--read-only</option></term>
+ <term><option>--link-journal=</option></term>
- <listitem><para>Mount the container's root file system (and any other file systems container in the container
- image) read-only. This has no effect on additional mounts made with <option>--bind=</option>,
- <option>--tmpfs=</option> and similar options. This mode is implied if the container image file or directory is
- marked read-only itself. It is also implied if <option>--volatile=</option> is used. In this case the container
- image on disk is strictly read-only, while changes are permitted but kept non-persistently in memory only. For
- further details, see below.</para></listitem>
+ <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>
+
+ </variablelist>
+
+ </refsect2><refsect2>
+ <title>Mount Options</title>
+
+ <variablelist>
+
<varlistentry>
<term><option>--bind=</option></term>
<term><option>--bind-ro=</option></term>
this switch.</para>
<para>Note that this option cannot be used to replace the root file system of the container with an overlay
- file system. However, the <option>--volatile=</option> option described below provides similar functionality,
+ file system. However, the <option>--volatile=</option> option described above provides similar functionality,
with a focus on implementing stateless operating system images.</para></listitem>
</varlistentry>
+ </variablelist>
- <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: a system and service manager as PID 1), 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 a service manager, 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 use the service or
- scope unit <command>systemd-nspawn</command> has been invoked in. If <option>--register=yes</option> is set
- this unit is registered with
- <citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>8</manvolnum></citerefentry>. 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>
- <para>Note that passing <option>--keep-unit</option> disables the effect of <option>--slice=</option> and
- <option>--property=</option>. Use <option>--keep-unit</option> and <option>--register=no</option> in
- combination to disable any kind of unit allocation or registration with
- <command>systemd-machined</command>.</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>
+ </refsect2><refsect2>
+ <title>Input/Output Options</title>
+ <variablelist>
<varlistentry>
<term><option>--console=</option><replaceable>MODE</replaceable></term>
<listitem><para>Equivalent to <option>--console=pipe</option>.</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
- writable <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>overlay</option> the read-only root file system is combined with a writable
- <filename>tmpfs</filename> instance through <literal>overlayfs</literal>, so that it appears at it normally
- would, but any changes are applied to the temporary file system only and lost when the container is
- terminated. When the mode parameter is specified as <option>no</option> (the default), the whole OS tree is
- made available writable (unless <option>--read-only</option> is specified, see above).</para>
-
- <para>Note that if one of the volatile modes is chosen, its effect is limited to the root file system (or
- <filename>/var/</filename> in case of <option>state</option>), and any other mounts placed in the hierarchy are
- unaffected — regardless if they are established automatically (e.g. the EFI system partition that might be
- mounted to <filename>/efi/</filename> or <filename>/boot/</filename>) or explicitly (e.g. through an additional
- command line option such as <option>--bind=</option>, see above). This means, even if
- <option>--volatile=overlay</option> is used changes to <filename>/efi/</filename> or
- <filename>/boot/</filename> are prohibited in case such a partition exists in the container image operated on,
- and even if <option>--volatile=state</option> is used the hypothetical file <filename>/etc/foobar</filename> is
- potentially writable if <option>--bind=/etc/foobar</option> if used to mount it from outside the read-only
- container <filename>/etc</filename> directory.</para>
-
- <para>The <option>--ephemeral</option> option is closely related to this setting, and provides similar
- behaviour by making a temporary, ephemeral copy of the whole OS image and executing that. For further details,
- see above.</para>
-
- <para>The <option>--tmpfs=</option> and <option>--overlay=</option> options provide similar functionality, but
- for specific sub-directories of the OS image only. For details, see above.</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 setting this option to <option>yes</option> or <option>state</option> 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>. The <option>overlay</option> option does not require any particular
- preparations in the OS, but do note that <literal>overlayfs</literal> behaviour differs from regular file
- systems in a number of ways, and hence compatibility is limited.</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="no-pager" />
<xi:include href="standard-options.xml" xpointer="help" />
<xi:include href="standard-options.xml" xpointer="version" />
</variablelist>
-
+ </refsect2>
</refsect1>
+ <xi:include href="less-variables.xml" />
+
<refsect1>
<title>Examples</title>
<programlisting># machinectl pull-raw --verify=no \
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
-# systemd-nspawn -M Fedora-Cloud-Base-&fedora_latest_version;-&fedora_cloud_release;.x86_64.raw</programlisting>
+# systemd-nspawn -M Fedora-Cloud-Base-&fedora_latest_version;-&fedora_cloud_release;.x86_64</programlisting>
<para>This downloads an image using
<citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
<title>Boot a minimal
<ulink url="https://www.archlinux.org">Arch Linux</ulink> distribution in a container</title>
- <programlisting># pacstrap -c -d ~/arch-tree/ base
+ <programlisting># pacstrap -c ~/arch-tree/ base
# systemd-nspawn -bD ~/arch-tree/</programlisting>
<para>This installs a minimal Arch Linux distribution into the
projects / thirdparty / systemd.git / blobdiff