test-hostname-util: add assert_se's to make coverity happy

[thirdparty/systemd.git] / man / machinectl.xml

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<refentry id="machinectl" conditional='ENABLE_MACHINED'
    xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>machinectl</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>machinectl</refentrytitle>
    <manvolnum>1</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>machinectl</refname>
    <refpurpose>Control the systemd machine manager</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>machinectl</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="req">COMMAND</arg>
      <arg choice="opt" rep="repeat">NAME</arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><command>machinectl</command> may be used to introspect and
    control the state of the
    <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    virtual machine and container registration manager
    <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>

    <para><command>machinectl</command> may be used to execute
    operations on machines and images. Machines in this sense are
    considered running instances of:</para>

    <itemizedlist>
      <listitem><para>Virtual Machines (VMs) that virtualize hardware
      to run full operating system (OS) instances (including their kernels)
      in a virtualized environment on top of the host OS.</para></listitem>

      <listitem><para>Containers that share the hardware and
      OS kernel with the host OS, in order to run
      OS userspace instances on top the host OS.</para></listitem>

      <listitem><para>The host system itself.</para></listitem>
    </itemizedlist>

    <para>Machines are identified by names that follow the same rules
    as UNIX and DNS host names. For details, see below.</para>

    <para>Machines are instantiated from disk or file system images that
    frequently — but not necessarily — carry the same name as machines running
    from them. Images in this sense may be:</para>

    <itemizedlist>
      <listitem><para>Directory trees containing an OS, including the
      top-level directories <filename>/usr</filename>,
      <filename>/etc</filename>, and so on.</para></listitem>

      <listitem><para>btrfs subvolumes containing OS trees, similar to
      normal directory trees.</para></listitem>

      <listitem><para>Binary "raw" disk images containing MBR or GPT
      partition tables and Linux file system partitions.</para></listitem>

      <listitem><para>The file system tree of the host OS itself.</para></listitem>
    </itemizedlist>

  </refsect1>

  <refsect1>
    <title>Options</title>

    <para>The following options are understood:</para>

    <variablelist>
      <varlistentry>
        <term><option>-p</option></term>
        <term><option>--property=</option></term>

        <listitem><para>When showing machine or image properties,
        limit the output to certain properties as specified by the
        argument. If not specified, all set properties are shown. The
        argument should be a property name, such as
        <literal>Name</literal>. If specified more than once, all
        properties with the specified names are
        shown.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-a</option></term>
        <term><option>--all</option></term>

        <listitem><para>When showing machine or image properties, show
        all properties regardless of whether they are set or
        not.</para>

        <para>When listing VM or container images, do not suppress
        images beginning in a dot character
        (<literal>.</literal>).</para>

        <para>When cleaning VM or container images, remove all images, not just hidden ones.</para></listitem>
      </varlistentry>

       <varlistentry>
        <term><option>--value</option></term>

        <listitem><para>When printing properties with <command>show</command>, only print the value,
        and skip the property name and <literal>=</literal>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-l</option></term>
        <term><option>--full</option></term>

        <listitem><para>Do not ellipsize process tree entries.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--no-ask-password</option></term>

        <listitem><para>Do not query the user for authentication for
        privileged operations.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--kill-who=</option></term>

        <listitem><para>When used with <command>kill</command>, choose
        which processes to kill. Must be one of
        <option>leader</option>, or <option>all</option> to select
        whether to kill only the leader process of the machine or all
        processes of the machine. If omitted, defaults to
        <option>all</option>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-s</option></term>
        <term><option>--signal=</option></term>

        <listitem><para>When used with <command>kill</command>, choose
        which signal to send to selected processes. Must be one of the
        well-known signal specifiers, such as
        <constant>SIGTERM</constant>, <constant>SIGINT</constant> or
        <constant>SIGSTOP</constant>. If omitted, defaults to
        <constant>SIGTERM</constant>.</para></listitem>
      </varlistentry>

      <varlistentry>
         <term><option>--uid=</option></term>

         <listitem><para>When used with the <command>shell</command> command, chooses the user ID to
         open the interactive shell session as. If the argument to the <command>shell</command>
         command also specifies a user name, this option is ignored. If the name is not specified
         in either way, <literal>root</literal> will be used by default. Note that this switch is
         not supported for the <command>login</command> command (see below).</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>When used with the <command>shell</command> command, sets an environment
         variable to pass to the executed shell. Takes an environment variable name and value,
         separated by <literal>=</literal>. This switch may be used multiple times to set multiple
         environment variables. Note that this switch is not supported for the
         <command>login</command> command (see below).</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--mkdir</option></term>

        <listitem><para>When used with <command>bind</command>, creates the destination file or directory before
        applying the bind mount. Note that even though the name of this option suggests that it is suitable only for
        directories, this option also creates the destination file node to mount over if the the object to mount is not
        a directory, but a regular file, device node, socket or FIFO.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--read-only</option></term>

        <listitem><para>When used with <command>bind</command>, creates a read-only bind mount.</para>

        <para>When used with <command>clone</command>, <command>import-raw</command> or <command>import-tar</command> a
        read-only container or VM image is created.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-n</option></term>
        <term><option>--lines=</option></term>

        <listitem><para>When used with <command>status</command>,
        controls the number of journal lines to show, counting from
        the most recent ones. Takes a positive integer argument.
        Defaults to 10.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-o</option></term>
        <term><option>--output=</option></term>

        <listitem><para>When used with <command>status</command>,
        controls the formatting of the journal entries that are shown.
        For the available choices, see
        <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
        Defaults to <literal>short</literal>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--verify=</option></term>

        <listitem><para>When downloading a container or VM image,
        specify whether the image shall be verified before it is made
        available. Takes one of <literal>no</literal>,
        <literal>checksum</literal> and <literal>signature</literal>.
        If <literal>no</literal>, no verification is done. If
        <literal>checksum</literal> is specified, the download is
        checked for integrity after the transfer is complete, but no
        signatures are verified. If <literal>signature</literal> is
        specified, the checksum is verified and the image's signature
        is checked against a local keyring of trustable vendors. It is
        strongly recommended to set this option to
        <literal>signature</literal> if the server and protocol
        support this. Defaults to
        <literal>signature</literal>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--force</option></term>

        <listitem><para>When downloading a container or VM image, and
        a local copy by the specified local machine name already
        exists, delete it first and replace it by the newly downloaded
        image.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--format=</option></term>

        <listitem><para>When used with the <option>export-tar</option>
        or <option>export-raw</option> commands, specifies the
        compression format to use for the resulting file. Takes one of
        <literal>uncompressed</literal>, <literal>xz</literal>,
        <literal>gzip</literal>, <literal>bzip2</literal>. By default,
        the format is determined automatically from the image file
        name passed.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--max-addresses=</option></term>

        <listitem><para>When used with the <option>list-machines</option>
        command, limits the number of ip addresses output for every machine.
        Defaults to 1. All addresses can be requested with <literal>all</literal>
        as argument to <option>--max-addresses</option> . If the argument to
        <option>--max-addresses</option> is less than the actual number
        of addresses, <literal>...</literal>follows the last address.
        If multiple addresses are to be written for a given machine, every
        address except the first one is on a new line and is followed by
        <literal>,</literal> if another address will be output afterwards. </para></listitem>
      </varlistentry>

      <xi:include href="user-system-options.xml" xpointer="host" />

      <varlistentry>
        <term><option>-M</option></term>
        <term><option>--machine=</option></term>

        <listitem><para>Connect to
        <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
        running in a local container, to perform the specified operation within
        the container.</para></listitem>
      </varlistentry>

      <xi:include href="standard-options.xml" xpointer="no-pager" />
      <xi:include href="standard-options.xml" xpointer="no-legend" />
      <xi:include href="standard-options.xml" xpointer="help" />
      <xi:include href="standard-options.xml" xpointer="version" />
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Commands</title>

    <para>The following commands are understood:</para>

    <refsect2><title>Machine Commands</title><variablelist>

      <varlistentry>
        <term><command>list</command></term>

        <listitem><para>List currently running (online) virtual
        machines and containers. To enumerate machine images that can
        be started, use <command>list-images</command> (see
        below). Note that this command hides the special
        <literal>.host</literal> machine by default. Use the
        <option>--all</option> switch to show it.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>status</command> <replaceable>NAME</replaceable>…</term>

        <listitem><para>Show runtime status information about
        one or more virtual machines and containers, followed by the
        most recent log data from the journal. This function is
        intended to generate human-readable output. If you are looking
        for computer-parsable output, use <command>show</command>
        instead. Note that the log data shown is reported by the
        virtual machine or container manager, and frequently contains
        console output of the machine, but not necessarily journal
        contents of the machine itself.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>show</command> [<replaceable>NAME</replaceable>…]</term>

        <listitem><para>Show properties of one or more registered virtual machines or containers or the manager
        itself. If no argument is specified, properties of the manager will be shown. If a NAME is specified,
        properties of this virtual machine or container are shown. By default, empty properties are suppressed. Use
        <option>--all</option> to show those too.  To select specific properties to show, use
        <option>--property=</option>. This command is intended to be used whenever computer-parsable output is
        required, and does not print the control group tree or journal entries. Use <command>status</command> if you
        are looking for formatted human-readable output.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>start</command> <replaceable>NAME</replaceable>…</term>

        <listitem><para>Start a container as a system service, using
        <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
        This starts <filename>systemd-nspawn@.service</filename>,
        instantiated for the specified machine name, similar to the
        effect of <command>systemctl start</command> on the service
        name. <command>systemd-nspawn</command> looks for a container
        image by the specified name in
        <filename>/var/lib/machines/</filename> (and other search
        paths, see below) and runs it. Use
        <command>list-images</command> (see below) for listing
        available container images to start.</para>

        <para>Note that
        <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
        also interfaces with a variety of other container and VM
        managers, <command>systemd-nspawn</command> is just one
        implementation of it. Most of the commands available in
        <command>machinectl</command> may be used on containers or VMs
        controlled by other managers, not just
        <command>systemd-nspawn</command>. Starting VMs and container
        images on those managers requires manager-specific
        tools.</para>

        <para>To interactively start a container on the command line
        with full access to the container's console, please invoke
        <command>systemd-nspawn</command> directly. To stop a running
        container use <command>machinectl poweroff</command>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>login</command> [<replaceable>NAME</replaceable>]</term>

        <listitem><para>Open an interactive terminal login session in
        a container or on the local host. If an argument is supplied,
        it refers to the container machine to connect to. If none is
        specified, or the container name is specified as the empty
        string, or the special machine name <literal>.host</literal>
        (see below) is specified, the connection is made to the local
        host instead. This will create a TTY connection to a specific
        container or the local host and asks for the execution of a
        getty on it. Note that this is only supported for containers
        running
        <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
        as init system.</para>

        <para>This command will open a full login prompt on the
        container or the local host, which then asks for username and
        password. Use <command>shell</command> (see below) or
        <citerefentry><refentrytitle>systemd-run</refentrytitle><manvolnum>1</manvolnum></citerefentry>
        with the <option>--machine=</option> switch to directly invoke
        a single command, either interactively or in the
        background.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>shell</command> [[<replaceable>NAME</replaceable>@]<replaceable>NAME</replaceable> [<replaceable>PATH</replaceable> [<replaceable>ARGUMENTS</replaceable>…]]] </term>

        <listitem><para>Open an interactive shell session in a
        container or on the local host. The first argument refers to
        the container machine to connect to. If none is specified, or
        the machine name is specified as the empty string, or the
        special machine name <literal>.host</literal> (see below) is
        specified, the connection is made to the local host
        instead. This works similar to <command>login</command> but
        immediately invokes a user process. This command runs the
        specified executable with the specified arguments, or
        <filename>/bin/sh</filename> if none is specified. By default,
        opens a <literal>root</literal> shell, but by using
        <option>--uid=</option>, or by prefixing the machine name with
        a username and an <literal>@</literal> character, a different
        user may be selected. Use <option>--setenv=</option> to set
        environment variables for the executed process.</para>

        <para>Note that <command>machinectl shell</command> does not propagate the exit code/status of the invoked
        shell process. Use <command>systemd-run</command> instead if that information is required (see below).</para>

        <para>When using the <command>shell</command> command without
        arguments, (thus invoking the executed shell or command on the
        local host), it is in many ways similar to a <citerefentry
        project='die-net'><refentrytitle>su</refentrytitle><manvolnum>1</manvolnum></citerefentry>
        session, but, unlike <command>su</command>, completely isolates
        the new session from the originating session, so that it
        shares no process or session properties, and is in a clean and
        well-defined state. It will be tracked in a new utmp, login,
        audit, security and keyring session, and will not inherit any
        environment variables or resource limits, among other
        properties.</para>

        <para>Note that <citerefentry><refentrytitle>systemd-run</refentrytitle><manvolnum>1</manvolnum></citerefentry>
        with its <option>--machine=</option> switch may be used in place of the <command>machinectl shell</command>
        command, and allows non-interactive operation, more detailed and low-level configuration of the invoked unit,
        as well as access to runtime and exit code/status information of the invoked shell process. In particular, use
        <command>systemd-run</command>'s <option>--wait</option> switch to propagate exit status information of the
        invoked process. Use <command>systemd-run</command>'s <option>--pty</option> switch for acquiring an
        interactive shell, similar to <command>machinectl shell</command>. In general, <command>systemd-run</command>
        is preferable for scripting purposes. However, note that <command>systemd-run</command> might require higher
        privileges than <command>machinectl shell</command>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>enable</command> <replaceable>NAME</replaceable>…</term>
        <term><command>disable</command> <replaceable>NAME</replaceable>…</term>

        <listitem><para>Enable or disable a container as a system
        service to start at system boot, using
        <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
        This enables or disables
        <filename>systemd-nspawn@.service</filename>, instantiated for
        the specified machine name, similar to the effect of
        <command>systemctl enable</command> or <command>systemctl
        disable</command> on the service name.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>poweroff</command> <replaceable>NAME</replaceable>…</term>

        <listitem><para>Power off one or more containers. This will
        trigger a reboot by sending SIGRTMIN+4 to the container's init
        process, which causes systemd-compatible init systems to shut
        down cleanly. Use <command>stop</command> as alias for <command>poweroff</command>.
        This operation does not work on containers that do not run a
        <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>-compatible
        init system, such as sysvinit. Use
        <command>terminate</command> (see below) to immediately
        terminate a container or VM, without cleanly shutting it
        down.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>reboot</command> <replaceable>NAME</replaceable>…</term>

        <listitem><para>Reboot one or more containers. This will
        trigger a reboot by sending SIGINT to the container's init
        process, which is roughly equivalent to pressing Ctrl+Alt+Del
        on a non-containerized system, and is compatible with
        containers running any system manager.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>terminate</command> <replaceable>NAME</replaceable>…</term>

        <listitem><para>Immediately terminates a virtual machine or
        container, without cleanly shutting it down. This kills all
        processes of the virtual machine or container and deallocates
        all resources attached to that instance. Use
        <command>poweroff</command> to issue a clean shutdown
        request.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>kill</command> <replaceable>NAME</replaceable>…</term>

        <listitem><para>Send a signal to one or more processes of the
        virtual machine or container. This means processes as seen by
        the host, not the processes inside the virtual machine or
        container. Use <option>--kill-who=</option> to select which
        process to kill. Use <option>--signal=</option> to select the
        signal to send.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>bind</command> <replaceable>NAME</replaceable> <replaceable>PATH</replaceable> [<replaceable>PATH</replaceable>]</term>

        <listitem><para>Bind mounts a file or directory from the host into the specified container. The first path
        argument is the source file or directory on the host, the second path argument is the destination file or
        directory in the container. When the latter is omitted, the destination path in the container is the same as
        the source path on the host. When combined with the <option>--read-only</option> switch, a ready-only bind
        mount is created. When combined with the <option>--mkdir</option> switch, the destination path is first created
        before the mount is applied. Note that this option is currently only supported for
        <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry> containers,
        and only if user namespacing (<option>--private-users</option>) is not used. This command supports bind
        mounting directories, regular files, device nodes, <constant>AF_UNIX</constant> socket nodes, as well as
        FIFOs.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>copy-to</command> <replaceable>NAME</replaceable> <replaceable>PATH</replaceable> [<replaceable>PATH</replaceable>]</term>

        <listitem><para>Copies files or directories from the host
        system into a running container. Takes a container name,
        followed by the source path on the host and the destination
        path in the container. If the destination path is omitted, the
        same as the source path is used.</para>

        <para>If host and container share the same user and group namespace, file ownership by numeric user ID and
        group ID is preserved for the copy, otherwise all files and directories in the copy will be owned by the root
        user and group (UID/GID 0).</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>copy-from</command> <replaceable>NAME</replaceable> <replaceable>PATH</replaceable> [<replaceable>PATH</replaceable>]</term>

        <listitem><para>Copies files or directories from a container
        into the host system. Takes a container name, followed by the
        source path in the container the destination path on the host.
        If the destination path is omitted, the same as the source path
        is used.</para>

        <para>If host and container share the same user and group namespace, file ownership by numeric user ID and
        group ID is preserved for the copy, otherwise all files and directories in the copy will be owned by the root
        user and group (UID/GID 0).</para></listitem>
      </varlistentry>
    </variablelist></refsect2>

    <refsect2><title>Image Commands</title><variablelist>

      <varlistentry>
        <term><command>list-images</command></term>

        <listitem><para>Show a list of locally installed container and
        VM images. This enumerates all raw disk images and container
        directories and subvolumes in
        <filename>/var/lib/machines/</filename> (and other search
        paths, see below). Use <command>start</command> (see above) to
        run a container off one of the listed images. Note that, by
        default, containers whose name begins with a dot
        (<literal>.</literal>) are not shown. To show these too,
        specify <option>--all</option>. Note that a special image
        <literal>.host</literal> always implicitly exists and refers
        to the image the host itself is booted from.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>image-status</command> [<replaceable>NAME</replaceable>…]</term>

        <listitem><para>Show terse status information about one or
        more container or VM images. This function is intended to
        generate human-readable output. Use
        <command>show-image</command> (see below) to generate
        computer-parsable output instead.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>show-image</command> [<replaceable>NAME</replaceable>…]</term>

        <listitem><para>Show properties of one or more registered
        virtual machine or container images, or the manager itself. If
        no argument is specified, properties of the manager will be
        shown. If a NAME is specified, properties of this virtual
        machine or container image are shown. By default, empty
        properties are suppressed. Use <option>--all</option> to show
        those too. To select specific properties to show, use
        <option>--property=</option>. This command is intended to be
        used whenever computer-parsable output is required. Use
        <command>image-status</command> if you are looking for
        formatted human-readable output.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>clone</command> <replaceable>NAME</replaceable> <replaceable>NAME</replaceable></term>

        <listitem><para>Clones a container or VM image. The arguments specify the name of the image to clone and the
        name of the newly cloned image. Note that plain directory container images are cloned into btrfs subvolume
        images with this command, if the underlying file system supports this.  Note that cloning a container or VM
        image is optimized for file systems that support copy-on-write, and might not be efficient on others, due to
        file system limitations.</para>

        <para>Note that this command leaves host name, machine ID and
        all other settings that could identify the instance
        unmodified. The original image and the cloned copy will hence
        share these credentials, and it might be necessary to manually
        change them in the copy.</para>

        <para>If combined with the <option>--read-only</option> switch a read-only cloned image is
        created.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>rename</command> <replaceable>NAME</replaceable> <replaceable>NAME</replaceable></term>

        <listitem><para>Renames a container or VM image. The
        arguments specify the name of the image to rename and the new
        name of the image.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>read-only</command> <replaceable>NAME</replaceable> [<replaceable>BOOL</replaceable>]</term>

        <listitem><para>Marks or (unmarks) a container or VM image
        read-only. Takes a VM or container image name, followed by a
        boolean as arguments. If the boolean is omitted, positive is
        implied, i.e. the image is marked read-only.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>remove</command> <replaceable>NAME</replaceable>…</term>

        <listitem><para>Removes one or more container or VM images.
        The special image <literal>.host</literal>, which refers to
        the host's own directory tree, may not be
        removed.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>set-limit</command> [<replaceable>NAME</replaceable>] <replaceable>BYTES</replaceable></term>

        <listitem><para>Sets the maximum size in bytes that a specific
        container or VM image, or all images, may grow up to on disk
        (disk quota). Takes either one or two parameters. The first,
        optional parameter refers to a container or VM image name. If
        specified, the size limit of the specified image is changed. If
        omitted, the overall size limit of the sum of all images stored
        locally is changed. The final argument specifies the size
        limit in bytes, possibly suffixed by the usual K, M, G, T
        units. If the size limit shall be disabled, specify
        <literal>-</literal> as size.</para>

        <para>Note that per-container size limits are only supported
        on btrfs file systems. Also note that, if
        <command>set-limit</command> is invoked without an image
        parameter, and <filename>/var/lib/machines</filename> is
        empty, and the directory is not located on btrfs, a btrfs
        loopback file is implicitly created as
        <filename>/var/lib/machines.raw</filename> with the given
        size, and mounted to
        <filename>/var/lib/machines</filename>. The size of the
        loopback may later be readjusted with
        <command>set-limit</command>, as well. If such a
        loopback-mounted <filename>/var/lib/machines</filename>
        directory is used, <command>set-limit</command> without an image
        name alters both the quota setting within the file system as
        well as the loopback file and file system size
        itself.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>clean</command></term>

        <listitem><para>Remove hidden VM or container images (or all). This command removes all hidden machine images
        from <filename>/var/lib/machines</filename>, i.e. those whose name begins with a dot. Use <command>machinectl
        list-images --all</command> to see a list of all machine images, including the hidden ones.</para>

        <para>When combined with the <option>--all</option> switch removes all images, not just hidden ones. This
        command effectively empties <filename>/var/lib/machines</filename>.</para>

        <para>Note that commands such as <command>machinectl pull-tar</command> or <command>machinectl
        pull-raw</command> usually create hidden, read-only, unmodified machine images from the downloaded image first,
        before cloning a writable working copy of it, in order to avoid duplicate downloads in case of images that are
        reused multiple times. Use <command>machinectl clean</command> to remove old, hidden images created this
        way.</para></listitem>
      </varlistentry>

    </variablelist></refsect2>

    <refsect2><title>Image Transfer Commands</title><variablelist>

      <varlistentry>
        <term><command>pull-tar</command> <replaceable>URL</replaceable> [<replaceable>NAME</replaceable>]</term>

        <listitem><para>Downloads a <filename>.tar</filename>
        container image from the specified URL, and makes it available
        under the specified local machine name. The URL must be of
        type <literal>http://</literal> or
        <literal>https://</literal>, and must refer to a
        <filename>.tar</filename>, <filename>.tar.gz</filename>,
        <filename>.tar.xz</filename> or <filename>.tar.bz2</filename>
        archive file. If the local machine name is omitted, it
        is automatically derived from the last component of the URL,
        with its suffix removed.</para>

        <para>The image is verified before it is made available, unless
        <option>--verify=no</option> is specified.
        Verification is done either via an inline signed file with the name
        of the image and the suffix <filename>.sha256</filename> or via
        separate <filename>SHA256SUMS</filename> and
        <filename>SHA256SUMS.gpg</filename> files.
        The signature files need to be made available on the same web
        server, under the same URL as the <filename>.tar</filename> file.
        With <option>--verify=checksum</option>, only the SHA256 checksum
        for the file is verified, based on the <filename>.sha256</filename>
        suffixed file or the<filename>SHA256SUMS</filename> file.
        With <option>--verify=signature</option>, the sha checksum file is
        first verified with the inline signature in the
        <filename>.sha256</filename> file or the detached GPG signature file
        <filename>SHA256SUMS.gpg</filename>.
        The public key for this verification step needs to be available in
        <filename>/usr/lib/systemd/import-pubring.gpg</filename> or
        <filename>/etc/systemd/import-pubring.gpg</filename>.</para>

        <para>The container image will be downloaded and stored in a
        read-only subvolume in
        <filename>/var/lib/machines/</filename> that is named after
        the specified URL and its HTTP etag. A writable snapshot is
        then taken from this subvolume, and named after the specified
        local name. This behavior ensures that creating multiple
        container instances of the same URL is efficient, as multiple
        downloads are not necessary. In order to create only the
        read-only image, and avoid creating its writable snapshot,
        specify <literal>-</literal> as local machine name.</para>

        <para>Note that the read-only subvolume is prefixed with
        <filename>.tar-</filename>, and is thus not shown by
        <command>list-images</command>, unless <option>--all</option>
        is passed.</para>

        <para>Note that pressing C-c during execution of this command
        will not abort the download. Use
        <command>cancel-transfer</command>, described
        below.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>pull-raw</command> <replaceable>URL</replaceable> [<replaceable>NAME</replaceable>]</term>

        <listitem><para>Downloads a <filename>.raw</filename>
        container or VM disk image from the specified URL, and makes
        it available under the specified local machine name. The URL
        must be of type <literal>http://</literal> or
        <literal>https://</literal>. The container image must either
        be a <filename>.qcow2</filename> or raw disk image, optionally
        compressed as <filename>.gz</filename>,
        <filename>.xz</filename>, or <filename>.bz2</filename>. If the
        local machine name is omitted, it is automatically
        derived from the last component of the URL, with its suffix
        removed.</para>

        <para>Image verification is identical for raw and tar images
        (see above).</para>

        <para>If the downloaded image is in
        <filename>.qcow2</filename> format it is converted into a raw
        image file before it is made available.</para>

        <para>Downloaded images of this type will be placed as
        read-only <filename>.raw</filename> file in
        <filename>/var/lib/machines/</filename>. A local, writable
        (reflinked) copy is then made under the specified local
        machine name. To omit creation of the local, writable copy
        pass <literal>-</literal> as local machine name.</para>

        <para>Similar to the behavior of <command>pull-tar</command>,
        the read-only image is prefixed with
        <filename>.raw-</filename>, and thus not shown by
        <command>list-images</command>, unless <option>--all</option>
        is passed.</para>

        <para>Note that pressing C-c during execution of this command
        will not abort the download. Use
        <command>cancel-transfer</command>, described
        below.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>import-tar</command> <replaceable>FILE</replaceable> [<replaceable>NAME</replaceable>]</term>
        <term><command>import-raw</command> <replaceable>FILE</replaceable> [<replaceable>NAME</replaceable>]</term>
        <listitem><para>Imports a TAR or RAW container or VM image,
        and places it under the specified name in
        <filename>/var/lib/machines/</filename>. When
        <command>import-tar</command> is used, the file specified as
        the first argument should be a tar archive, possibly compressed
        with xz, gzip or bzip2. It will then be unpacked into its own
        subvolume in <filename>/var/lib/machines</filename>. When
        <command>import-raw</command> is used, the file should be a
        qcow2 or raw disk image, possibly compressed with xz, gzip or
        bzip2. If the second argument (the resulting image name) is
        not specified, it is automatically derived from the file
        name. If the filename is passed as <literal>-</literal>, the
        image is read from standard input, in which case the second
        argument is mandatory.</para>

        <para>Both <command>pull-tar</command> and <command>pull-raw</command>
        will resize <filename>/var/lib/machines.raw</filename> and the
        filesystem therein as necessary. Optionally, the
        <option>--read-only</option> switch may be used to create a
        read-only container or VM image. No cryptographic validation
        is done when importing the images.</para>

        <para>Much like image downloads, ongoing imports may be listed
        with <command>list-transfers</command> and aborted with
        <command>cancel-transfer</command>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>export-tar</command> <replaceable>NAME</replaceable> [<replaceable>FILE</replaceable>]</term>
        <term><command>export-raw</command> <replaceable>NAME</replaceable> [<replaceable>FILE</replaceable>]</term>
        <listitem><para>Exports a TAR or RAW container or VM image and
        stores it in the specified file. The first parameter should be
        a VM or container image name. The second parameter should be a
        file path the TAR or RAW image is written to. If the path ends
        in <literal>.gz</literal>, the file is compressed with gzip, if
        it ends in <literal>.xz</literal>, with xz, and if it ends in
        <literal>.bz2</literal>, with bzip2. If the path ends in
        neither, the file is left uncompressed. If the second argument
        is missing, the image is written to standard output. The
        compression may also be explicitly selected with the
        <option>--format=</option> switch. This is in particular
        useful if the second parameter is left unspecified.</para>

        <para>Much like image downloads and imports, ongoing exports
        may be listed with <command>list-transfers</command> and
        aborted with
        <command>cancel-transfer</command>.</para>

        <para>Note that, currently, only directory and subvolume images
        may be exported as TAR images, and only raw disk images as RAW
        images.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>list-transfers</command></term>

        <listitem><para>Shows a list of container or VM image
        downloads, imports and exports that are currently in
        progress.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>cancel-transfers</command> <replaceable>ID</replaceable>…</term>

        <listitem><para>Aborts a download, import or export of the
        container or VM image with the specified ID. To list ongoing
        transfers and their IDs, use
        <command>list-transfers</command>. </para></listitem>
      </varlistentry>

    </variablelist></refsect2>

  </refsect1>

  <refsect1>
    <title>Machine and Image Names</title>

    <para>The <command>machinectl</command> tool operates on machines
    and images whose names must be chosen following strict
    rules. Machine names must be suitable for use as host names
    following a conservative subset of DNS and UNIX/Linux
    semantics. Specifically, they must consist of one or more
    non-empty label strings, separated by dots. No leading or trailing
    dots are allowed. No sequences of multiple dots are allowed. The
    label strings may only consist of alphanumeric characters as well
    as the dash and underscore. The maximum length of a machine name
    is 64 characters.</para>

    <para>A special machine with the name <literal>.host</literal>
    refers to the running host system itself. This is useful for execution
    operations or inspecting the host system as well. Note that
    <command>machinectl list</command> will not show this special
    machine unless the <option>--all</option> switch is specified.</para>

    <para>Requirements on image names are less strict, however, they must be
    valid UTF-8, must be suitable as file names (hence not be the
    single or double dot, and not include a slash), and may not
    contain control characters. Since many operations search for an
    image by the name of a requested machine, it is recommended to name
    images in the same strict fashion as machines.</para>

    <para>A special image with the name <literal>.host</literal>
    refers to the image of the running host system. It hence
    conceptually maps to the special <literal>.host</literal> machine
    name described above. Note that <command>machinectl
    list-images</command> will not show this special image either, unless
    <option>--all</option> is specified.</para>
  </refsect1>

  <refsect1>
    <title>Files and Directories</title>

    <para>Machine images are preferably stored in
    <filename>/var/lib/machines/</filename>, but are also searched for
    in <filename>/usr/local/lib/machines/</filename> and
    <filename>/usr/lib/machines/</filename>. For compatibility reasons,
    the directory <filename>/var/lib/container/</filename> is
    searched, too. Note that images stored below
    <filename>/usr</filename> are always considered read-only. It is
    possible to symlink machines images from other directories into
    <filename>/var/lib/machines/</filename> to make them available for
    control with <command>machinectl</command>.</para>

    <para>Note that some image operations are only supported,
    efficient or atomic on btrfs file systems. Due to this, if the
    <command>pull-tar</command>, <command>pull-raw</command>,
    <command>import-tar</command>, <command>import-raw</command> and
    <command>set-limit</command> commands notice that
    <filename>/var/lib/machines</filename> is empty and not located on
    btrfs, they will implicitly set up a loopback file
    <filename>/var/lib/machines.raw</filename> containing a btrfs file
    system that is mounted to
    <filename>/var/lib/machines</filename>. The size of this loopback
    file may be controlled dynamically with
    <command>set-limit</command>.</para>

    <para>Disk images are understood by
    <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    and <command>machinectl</command> in three formats:</para>

    <itemizedlist>
      <listitem><para>A simple directory tree, containing the files
      and directories of the container to boot.</para></listitem>

      <listitem><para>Subvolumes (on btrfs file systems), which are
      similar to the simple directories, described above. However,
      they have additional benefits, such as efficient cloning and
      quota reporting.</para></listitem>

      <listitem><para>"Raw" disk images, i.e. binary images of disks
      with a GPT or MBR partition table. Images of this type are
      regular files with the suffix
      <literal>.raw</literal>.</para></listitem>
    </itemizedlist>

    <para>See
    <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    for more information on image formats, in particular its
    <option>--directory=</option> and <option>--image=</option>
    options.</para>
  </refsect1>

  <refsect1>
    <title>Examples</title>
    <example>
      <title>Download an Ubuntu image and open a shell in it</title>

      <programlisting># machinectl pull-tar https://cloud-images.ubuntu.com/trusty/current/trusty-server-cloudimg-amd64-root.tar.gz
# systemd-nspawn -M trusty-server-cloudimg-amd64-root</programlisting>

      <para>This downloads and verifies the specified
      <filename>.tar</filename> image, and then uses
      <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>
      to open a shell in it.</para>
    </example>

    <example>
      <title>Download a Fedora image, set a root password in it, start
      it as service</title>

      <programlisting># machinectl pull-raw --verify=no https://dl.fedoraproject.org/pub/fedora/linux/releases/23/Cloud/x86_64/Images/Fedora-Cloud-Base-23-20151030.x86_64.raw.xz
# systemd-nspawn -M Fedora-Cloud-Base-23-20151030
# passwd
# exit
# machinectl start Fedora-Cloud-Base-23-20151030
# machinectl login Fedora-Cloud-Base-23-20151030</programlisting>

      <para>This downloads the specified <filename>.raw</filename>
      image with verification disabled. Then, a shell is opened in it
      and a root password is set. Afterwards the shell is left, and
      the machine started as system service. With the last command a
      login prompt into the container is requested.</para>
    </example>

    <example>
      <title>Exports a container image as tar file</title>

      <programlisting># machinectl export-tar fedora myfedora.tar.xz</programlisting>

      <para>Exports the container <literal>fedora</literal> as an
      xz-compressed tar file <filename>myfedora.tar.xz</filename> into the
      current directory.</para>
    </example>

    <example>
      <title>Create a new shell session</title>

      <programlisting># machinectl shell --uid=lennart</programlisting>

      <para>This creates a new shell session on the local host for
      the user ID <literal>lennart</literal>, in a <citerefentry
      project='die-net'><refentrytitle>su</refentrytitle><manvolnum>1</manvolnum></citerefentry>-like
      fashion.</para>
    </example>

  </refsect1>

  <refsect1>
    <title>Exit status</title>

    <para>On success, 0 is returned, a non-zero failure code
    otherwise.</para>
  </refsect1>

  <xi:include href="less-variables.xml" />

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
      <citerefentry project='die-net'><refentrytitle>tar</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry project='die-net'><refentrytitle>xz</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry project='die-net'><refentrytitle>gzip</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry project='die-net'><refentrytitle>bzip2</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>