Merge pull request #221 from utezduyar/man-cgtop-explain-max-cpu

[thirdparty/systemd.git] / man / systemd-detect-virt.xml

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<refentry id="systemd-detect-virt"
    xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>systemd-detect-virt</title>
    <productname>systemd</productname>

    <authorgroup>
      <author>
        <contrib>Developer</contrib>
        <firstname>Lennart</firstname>
        <surname>Poettering</surname>
        <email>lennart@poettering.net</email>
      </author>
    </authorgroup>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd-detect-virt</refentrytitle>
    <manvolnum>1</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd-detect-virt</refname>
    <refpurpose>Detect execution in a virtualized environment</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>systemd-detect-virt <arg choice="opt" rep="repeat">OPTIONS</arg></command>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><command>systemd-detect-virt</command> detects execution in
    a virtualized environment. It identifies the virtualization
    technology and can distinguish full VM virtualization from
    container virtualization. <filename>systemd-detect-virt</filename>
    exits with a return value of 0 (success) if a virtualization
    technology is detected, and non-zero (error) otherwise. By default
    any type of virtualization is detected, and the options
    <option>--container</option> and <option>--vm</option> can be used
    to limit what types of virtualization are detected.</para>

    <para>When executed without <option>--quiet</option> will print a
    short identifier for the detected virtualization technology. The
    following technologies are currently identified:</para>

    <table>
      <title>Known virtualization technologies (both
      VM, i.e. full hardware virtualization,
      and container, i.e. shared kernel virtualization)</title>
      <tgroup cols='3' align='left' colsep='1' rowsep='1'>
        <colspec colname="type" />
        <colspec colname="id" />
        <colspec colname="product" />
        <thead>
          <row>
      <entry>Type</entry>
      <entry>ID</entry>
      <entry>Product</entry>
          </row>
        </thead>
        <tbody>
          <row>
      <entry morerows="8">VM</entry>
      <entry><varname>qemu</varname></entry>
      <entry>QEMU software virtualization</entry>
          </row>

          <row>
      <entry><varname>kvm</varname></entry>
      <entry>Linux KVM kernel virtual machine</entry>
          </row>

          <row>
      <entry><varname>zvm</varname></entry>
      <entry>s390 z/VM</entry>
          </row>

          <row>
      <entry><varname>vmware</varname></entry>
      <entry>VMware Workstation or Server, and related products</entry>
          </row>

          <row>
      <entry><varname>microsoft</varname></entry>
      <entry>Hyper-V, also known as Viridian or Windows Server Virtualization</entry>
          </row>

          <row>
      <entry><varname>oracle</varname></entry>
      <entry>Oracle VM VirtualBox (historically marketed by innotek and Sun Microsystems)</entry>
          </row>

          <row>
      <entry><varname>xen</varname></entry>
      <entry>Xen hypervisor (only domU, not dom0)</entry>
          </row>

          <row>
      <entry><varname>bochs</varname></entry>
      <entry>Bochs Emulator</entry>
          </row>

          <row>
      <entry><varname>uml</varname></entry>
      <entry>User-mode Linux</entry>
          </row>

          <row>
      <entry morerows="5">container</entry>
      <entry><varname>openvz</varname></entry>
      <entry>OpenVZ/Virtuozzo</entry>
          </row>

          <row>
      <entry><varname>lxc</varname></entry>
      <entry>Linux container implementation by LXC</entry>
          </row>

          <row>
      <entry><varname>lxc-libvirt</varname></entry>
      <entry>Linux container implementation by libvirt</entry>
          </row>

          <row>
       <entry><varname>systemd-nspawn</varname></entry>
       <entry>systemd's minimal container implementation, see <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry></entry>
          </row>

          <row>
      <entry><varname>docker</varname></entry>
      <entry>Docker container manager</entry>
          </row>
        </tbody>
      </tgroup>
    </table>

    <para>If multiple virtualization solutions are used, only the
    "innermost" is detected and identified. That means if both VM
    virtualization and container virtualization are used in
    conjunction, only the latter will be identified (unless
    <option>--vm</option> is passed).</para>
  </refsect1>

  <refsect1>
    <title>Options</title>

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

    <variablelist>
      <varlistentry>
        <term><option>-c</option></term>
        <term><option>--container</option></term>

        <listitem><para>Only detects container virtualization (i.e.
        shared kernel virtualization).</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-v</option></term>
        <term><option>--vm</option></term>

        <listitem><para>Only detects VM virtualization (i.e. full
        hardware virtualization).</para></listitem>
      </varlistentry>

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

        <listitem><para>Suppress output of the virtualization
        technology identifier.</para></listitem>
      </varlistentry>

      <xi:include href="standard-options.xml" xpointer="help" />
      <xi:include href="standard-options.xml" xpointer="version" />
    </variablelist>

  </refsect1>

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

    <para>If a virtualization technology is detected, 0 is returned, a
    non-zero code otherwise.</para>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>