portablectl.xml

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<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->

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

  <refentryinfo>
    <title>portablectl</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>portablectl</refentrytitle>
    <manvolnum>1</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>portablectl</refname>
    <refpurpose>Attach, detach or inspect portable service images</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>portablectl</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>portablectl</command> may be used to attach, detach or inspect portable service images. It's
    primarily a command interfacing with
    <citerefentry><refentrytitle>systemd-portabled.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>

    <para>Portable service images contain an OS file system tree along with
    <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> unit file
    information. A service image may be "attached" to the local system. If attached, a set of unit files are copied
    from the image to the host, and extended with <varname>RootDirectory=</varname> or <varname>RootImage=</varname>
    assignments (in case of service units) pointing to the image file or directory, ensuring the services will run
    within the file system context of the image.</para>

    <para>Portable service images are an efficient way to bundle multiple related services and other units together,
    and transfer them as a whole between systems. When these images are attached the local system the contained units
    may run in most ways like regular system-provided units, either with full privileges or inside strict sandboxing,
    depending on the selected configuration. For more details, see
    <ulink url="https://systemd.io/PORTABLE_SERVICES">Portable Services</ulink>.</para>

    <para>Specifically portable service images may be of the following kind:</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. (These must be regular files, with the <filename>.raw</filename> suffix.)</para></listitem>
    </itemizedlist>

  </refsect1>

  <refsect1>
    <title>Commands</title>

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

    <variablelist>

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

        <listitem><para>List available portable service images. This will list all portable service images discovered
        in the portable image search paths (see below), along with brief metadata and state information. Note that many
        of the commands below may both operate on images inside and outside of the search paths. This command is hence
        mostly a convenience option, the commands are generally not restricted to what this list
        shows.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>attach</command> <replaceable>IMAGE</replaceable> [<replaceable>PREFIX…</replaceable>]</term>

        <listitem><para>Attach a portable service image to the host system. Expects a file system path to a portable
        service image file or directory as first argument. If the specified path contains no slash character
        (<literal>/</literal>) it is understood as image filename that is searched for in the portable service image
        search paths (see below). To reference a file in the current working directory prefix the filename with
        <literal>./</literal> to avoid this search path logic.</para>

        <para>When a portable service is attached four operations are executed:</para>

        <orderedlist>

          <listitem><para>All unit files of types <filename>.service</filename>, <filename>.socket</filename>,
          <filename>.target</filename>, <filename>.timer</filename> and <filename>.path</filename> which match the
          indicated unit file name prefix are copied from the image to the host's
          <filename>/etc/systemd/system.attached/</filename> directory (or
          <filename>/run/systemd/system.attached/</filename> — depending whether <option>--runtime</option> is
          specified, see above), which is included in the built-in unit search path of the system service
          manager.</para></listitem>

          <listitem><para>For unit files of type <filename>.service</filename> a drop-in is added to these copies that
          adds <varname>RootDirectory=</varname> or <varname>RootImage=</varname> settings (see
          <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
          details), that ensures these services are run within the file system of the originating portable service
          image.</para></listitem>

          <listitem><para>A second drop-in is created: the "profile" drop-in, that may contain additional security
          settings (and other settings). A number of profiles are available by default but administrators may define
          their own ones. See below.</para></listitem>

          <listitem><para>If the portable service image file is not already in the search path (see below), a symbolic
          link to it is created in <filename>/etc/portables/</filename> or
          <filename>/run/portables/</filename>, to make sure it is included in it.</para></listitem>
        </orderedlist>

        <para>By default all unit files whose names start with a prefix generated from the image's file name are copied
        out. Specifically, the prefix is determined from the image file name with any suffix such as
        <filename>.raw</filename> removed, truncated at the first occurrence of an underscore character
        (<literal>_</literal>), if there is one. The underscore logic is supposed to be used to versioning so that the
        an image file <filename>foobar_47.11.raw</filename> will result in a unit file matching prefix of
        <filename>foobar</filename>. This prefix is then compared with all unit files names contained in the image in
        the usual directories, but only unit file names where the prefix is followed by <literal>-</literal>,
        <literal>.</literal> or <literal>@</literal> are considered. Example: if a portable service image file is named
        <filename>foobar_47.11.raw</filename> then by default all its unit files with names such as
        <filename>foobar-quux-waldi.service</filename>, <filename>foobar.service</filename> or
        <filename>foobar@.service</filename> will be considered. It's possible to override the matching prefix: all
        strings listed on the command line after the image file name are considered prefixes, overriding the implicit
        logic where the prefix is derived from the image file name.</para>

        <para>By default, after the unit files are attached the service manager's configuration is reloaded, except
        when <option>--no-reload</option> is specified (see above). This ensures that the new units made available to
        the service manager are seen by it.</para>

        <para>If <option>--now</option> and/or <option>--enable</option> are passed, the portable service(s) are
        immediately started (blocking operation unless <option>--no-block</option> is passed) and/or enabled after
        attaching the image.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>detach</command> <replaceable>IMAGE</replaceable> [<replaceable>PREFIX…</replaceable>]</term>

        <listitem><para>Detaches a portable service image from the host. This undoes the operations executed by the
        <command>attach</command> command above, and removes the unit file copies, drop-ins and image symlink
        again. This command expects an image name or path as parameter. Note that if a path is specified only the last
        component of it (i.e. the file or directory name itself, not the path to it) is used for finding matching unit
        files. This is a convenience feature to allow all arguments passed as <command>attach</command> also to
        <command>detach</command>.</para></listitem>

        <para>If <option>--now</option> and/or <option>--enable</option> are passed, the portable service(s) are
        immediately stopped (blocking operation) and/or disabled before detaching the image. Prefix(es) are also accepted,
        to be used in case the unit names do not match the image name as described in the <command>attach</command>.</para>
      </varlistentry>

      <varlistentry>
        <term><command>reattach</command> <replaceable>IMAGE</replaceable> [<replaceable>PREFIX…</replaceable>]</term>

        <listitem><para>Detaches an existing portable service image from the host, and immediately attaches it again.
        This is useful in case the image was replaced. Running units are not stopped during the process. Partial matching,
        to allow for different versions in the image name, is allowed: only the part before the first <literal>_</literal>
        character has to match. If the new image doesn't exist, the existing one will not be detached. The parameters
        follow the same syntax as the <command>attach</command> command.</para></listitem>

        <para>If <option>--now</option> and/or <option>--enable</option> are passed, the portable service(s) are
        immediately stopped if removed, started and/or enabled if added, or restarted if updated. Prefixes are also
        accepted, in the same way as described in the <command>attach</command> case.</para>
      </varlistentry>

      <varlistentry>
        <term><command>inspect</command> <replaceable>IMAGE</replaceable> [<replaceable>PREFIX…</replaceable>]</term>

        <listitem><para>Extracts various metadata from a portable service image and presents it to the
        caller. Specifically, the
        <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry> file of the
        image is retrieved as well as all matching unit files. By default a short summary showing the most relevant
        metadata in combination with a list of matching unit files is shown (that is the unit files
        <command>attach</command> would install to the host system). If combined with <option>--cat</option> (see
        above), the <filename>os-release</filename> data and the units files' contents is displayed unprocessed. This
        command is useful to determine whether an image qualifies as portable service image, and which unit files are
        included. This command expects the path to the image as parameter, optionally followed by a list of unit file
        prefixes to consider, similar to the <command>attach</command> command described above.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>is-attached</command> <replaceable>IMAGE</replaceable></term>

        <listitem><para>Determines whether the specified image is currently attached or not. Unless combined with the
        <option>--quiet</option> switch this will show a short state identifier for the image. Specifically:</para>

        <table>
          <title>Image attachment states</title>
          <tgroup cols='2'>
            <colspec colname='state'/>
            <colspec colname='description'/>
            <thead>
              <row>
                <entry>State</entry>
                <entry>Description</entry>
              </row>
            </thead>
            <tbody>
              <row>
                <entry><option>detached</option></entry>
                <entry>The image is currently not attached.</entry>
              </row>
              <row>
                <entry><option>attached</option></entry>
                <entry>The image is currently attached, i.e. its unit files have been made available to the host system.</entry>
              </row>
              <row>
                <entry><option>attached-runtime</option></entry>
                <entry>Like <option>attached</option>, but the unit files have been made available transiently only, i.e. the <command>attach</command> command has been invoked with the <option>--runtime</option> option.</entry>
              </row>
              <row>
                <entry><option>enabled</option></entry>
                <entry>The image is currently attached, and at least one unit file associated with it has been enabled.</entry>
              </row>
              <row>
                <entry><option>enabled-runtime</option></entry>
                <entry>Like <option>enabled</option>, but the unit files have been made available transiently only, i.e. the <command>attach</command> command has been invoked with the <option>--runtime</option> option.</entry>
              </row>
              <row>
                <entry><option>running</option></entry>
                <entry>The image is currently attached, and at least one unit file associated with it is running.</entry>
              </row>
              <row>
                <entry><option>running-runtime</option></entry>
                <entry>The image is currently attached transiently, and at least one unit file associated with it is running.</entry>
              </row>
            </tbody>
          </tgroup>
        </table>

        </listitem>
      </varlistentry>

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

        <listitem><para>Marks or (unmarks) a portable service image read-only. Takes an 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>IMAGE</replaceable>…</term>

        <listitem><para>Removes one or more portable service images. Note that this command will only remove the
        specified image path itself — it refers to a symbolic link then the symbolic link is removed and not the
        image it points to.</para></listitem>
      </varlistentry>

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

        <listitem><para>Sets the maximum size in bytes that a specific portable service 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
        portable service 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-image size limits are only supported on btrfs file systems. Also, depending on
        <varname>BindPaths=</varname> settings in the portable service's unit files directories from the host might be
        visible in the image environment during runtime which are not affected by this setting, as only the image
        itself is counted against this limit.</para></listitem>
      </varlistentry>

    </variablelist>

  </refsect1>

  <refsect1>
    <title>Options</title>

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

    <variablelist>
      <varlistentry>
        <term><option>-q</option></term>
        <term><option>--quiet</option></term>

        <listitem><para>Suppresses additional informational output while running.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-p</option> <replaceable>PROFILE</replaceable></term>
        <term><option>--profile=</option><replaceable>PROFILE</replaceable></term>

        <listitem><para>When attaching an image, select the profile to use. By default the <literal>default</literal>
        profile is used. For details about profiles, see below.</para></listitem>
      </varlistentry>

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

        <listitem><para>When attaching an image, select whether to prefer copying or symlinking of files installed into
        the host system. Takes one of <literal>copy</literal> (to prefer copying of files), <literal>symlink</literal>
        (to prefer creation of symbolic links) or <literal>auto</literal> for an intermediary mode where security
        profile drop-ins are symlinked while unit files are copied. Note that this option expresses a preference only,
        in cases where symbolic links cannot be created — for example when the image operated on is a raw disk image,
        and hence not directly referentiable from the host file system — copying of files is used
        unconditionally.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--runtime</option></term>

        <listitem><para>When specified the unit and drop-in files are placed in
        <filename>/run/systemd/system.attached/</filename> instead of
        <filename>/etc/systemd/system.attached/</filename>. Images attached with this option set hence remain attached
        only until the next reboot, while they are normally attached persistently.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--no-reload</option></term>

        <listitem><para>Don't reload the service manager after attaching or detaching a portable service
        image. Normally the service manager is reloaded to ensure it is aware of added or removed unit
        files.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--cat</option></term>

        <listitem><para>When inspecting portable service images, show the (unprocessed) contents of the metadata files
        pulled from the image, instead of brief summaries. Specifically, this will show the
        <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry> and unit file
        contents of the image.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--enable</option></term>

        <listitem><para>Immediately enable/disable the portable service after attaching/detaching.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--now</option></term>

        <listitem><para>Immediately start/stop/restart the portable service after attaching/before
        detaching/after upgrading.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--no-block</option></term>

        <listitem><para>Don't block waiting for attach --now to complete.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--extension=</option><replaceable>PATH</replaceable></term>

        <listitem><para>Add an additional image <replaceable>PATH</replaceable> as an overlay on
        top of <replaceable>IMAGE</replaceable> when attaching/detaching. This argument can be specified
        multiple times, in which case the order in which images are laid down follows the rules specified in
        <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
        for the <varname>ExtensionImages=</varname> directive and for the
        <citerefentry><refentrytitle>systemd-sysext</refentrytitle><manvolnum>8</manvolnum></citerefentry> tool.
        The image(s) must contain an <filename>extension-release</filename> file with metadata that matches
        what is defined in the <filename>os-release</filename> of <replaceable>IMAGE</replaceable>. See:
        <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
        Images can be block images, btrfs subvolumes or directories. For more information on portable
        services with extensions, see the <literal>Extension Images</literal> paragraph on
        <ulink url="https://systemd.io/PORTABLE_SERVICES">Portable Services</ulink>.
        </para>

        <para>Note that the same extensions have to be specified, in the same order, when attaching
        and detaching.</para></listitem>
      </varlistentry>

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

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

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

    <para>Portable service images are preferably stored in <filename>/var/lib/portables/</filename>, but are also
    searched for in <filename>/etc/portables/</filename>, <filename>/run/systemd/portables/</filename>,
    <filename>/usr/local/lib/portables/</filename> and <filename>/usr/lib/portables/</filename>. It's recommended not
    to place image files directly in <filename>/etc/portables/</filename> or
    <filename>/run/systemd/portables/</filename> (as these are generally not suitable for storing large or non-textual
    data), but use these directories only for linking images located elsewhere into the image search path.</para>

    <para>When a portable service image is attached, matching unit files are copied onto the host into the
    <filename>/etc/systemd/system.attached/</filename> and <filename>/run/systemd/system.attached/</filename>
    directories. When an image is detached, the unit files are removed again from these directories.</para>
  </refsect1>

  <refsect1>
    <title>Profiles</title>

    <para>When portable service images are attached a "profile" drop-in is linked in, which may be used to enforce
    additional security (and other) restrictions locally. Four profile drop-ins are defined by default, and shipped in
    <filename>/usr/lib/systemd/portable/profile/</filename>. Additional, local profiles may be defined by placing them
    in <filename>/etc/systemd/portable/profile/</filename>. The default profiles are:</para>

    <table>
      <title>Profiles</title>
      <tgroup cols='2'>
        <colspec colname='state'/>
        <colspec colname='description'/>
        <thead>
          <row>
            <entry>Name</entry>
            <entry>Description</entry>
          </row>
        </thead>
        <tbody>
          <row>
            <entry><filename>default</filename></entry>
            <entry>This is the default profile if no other profile name is set via the <option>--profile=</option> (see above). It's fairly restrictive, but should be useful for common, unprivileged system workloads. This includes write access to the logging framework, as well as IPC access to the D-Bus system.</entry>
          </row>
          <row>
            <entry><filename>nonetwork</filename></entry>
            <entry>Very similar to <filename>default</filename>, but networking is turned off for any services of the portable service image.</entry>
          </row>
          <row>
            <entry><filename>strict</filename></entry>
            <entry>A profile with very strict settings. This profile excludes IPC (D-Bus) and network access.</entry>
          </row>
          <row>
            <entry><filename>trusted</filename></entry>
            <entry>A profile with very relaxed settings. In this profile the services run with full privileges.</entry>
          </row>
        </tbody>
      </tgroup>
    </table>

    <para>For details on these profiles and their effects see their precise definitions,
    e.g. <filename>/usr/lib/systemd/portable/profile/default/service.conf</filename> and similar.</para>
  </refsect1>

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

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

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

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-sysext</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>org.freedesktop.portable1</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-portabled.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>