man/systemd-detect-virt.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
   5
   6 <refentry id="systemd-detect-virt"
   7           xmlns:xi="http://www.w3.org/2001/XInclude">
   8
   9   <refentryinfo>
  10     <title>systemd-detect-virt</title>
  11     <productname>systemd</productname>
  12   </refentryinfo>
  13
  14   <refmeta>
  15     <refentrytitle>systemd-detect-virt</refentrytitle>
  16     <manvolnum>1</manvolnum>
  17   </refmeta>
  18
  19   <refnamediv>
  20     <refname>systemd-detect-virt</refname>
  21     <refpurpose>Detect execution in a virtualized environment</refpurpose>
  22   </refnamediv>
  23
  24   <refsynopsisdiv>
  25     <cmdsynopsis>
  26       <command>systemd-detect-virt</command>
  27       <arg choice="opt" rep="repeat">OPTIONS</arg>
  28     </cmdsynopsis>
  29   </refsynopsisdiv>
  30
  31   <refsect1>
  32     <title>Description</title>
  33
  34     <para><command>systemd-detect-virt</command> detects execution in
  35     a virtualized environment. It identifies the virtualization
  36     technology and can distinguish full machine virtualization from
  37     container virtualization. <filename>systemd-detect-virt</filename>
  38     exits with a return value of 0 (success) if a virtualization
  39     technology is detected, and non-zero (error) otherwise. By default,
  40     any type of virtualization is detected, and the options
  41     <option>--container</option> and <option>--vm</option> can be used
  42     to limit what types of virtualization are detected.</para>
  43
  44     <para>When executed without <option>--quiet</option> will print a
  45     short identifier for the detected virtualization technology. The
  46     following technologies are currently identified:</para>
  47
  48     <table>
  49       <title>Known virtualization technologies (both
  50       VM, i.e. full hardware virtualization,
  51       and container, i.e. shared kernel virtualization)</title>
  52       <tgroup cols='3' align='left' colsep='1' rowsep='1'>
  53         <colspec colname="type" />
  54         <colspec colname="id" />
  55         <colspec colname="product" />
  56         <thead>
  57           <row>
  58             <entry>Type</entry>
  59             <entry>ID</entry>
  60             <entry>Product</entry>
  61           </row>
  62         </thead>
  63         <tbody>
  64           <row>
  65             <entry valign="top" morerows="11">VM</entry>
  66             <entry><varname>qemu</varname></entry>
  67             <entry>QEMU software virtualization, without KVM</entry>
  68           </row>
  69
  70           <row>
  71             <entry><varname>kvm</varname></entry>
  72             <entry>Linux KVM kernel virtual machine, with whatever software, except Oracle Virtualbox</entry>
  73           </row>
  74
  75           <row>
  76             <entry><varname>zvm</varname></entry>
  77             <entry>s390 z/VM</entry>
  78           </row>
  79
  80           <row>
  81             <entry><varname>vmware</varname></entry>
  82             <entry>VMware Workstation or Server, and related products</entry>
  83           </row>
  84
  85           <row>
  86             <entry><varname>microsoft</varname></entry>
  87             <entry>Hyper-V, also known as Viridian or Windows Server Virtualization</entry>
  88           </row>
  89
  90           <row>
  91             <entry><varname>oracle</varname></entry>
  92             <entry>Oracle VM VirtualBox (historically marketed by innotek and Sun Microsystems), for legacy and KVM hypervisor</entry>
  93           </row>
  94
  95           <row>
  96             <entry><varname>xen</varname></entry>
  97             <entry>Xen hypervisor (only domU, not dom0)</entry>
  98           </row>
  99
 100           <row>
 101             <entry><varname>bochs</varname></entry>
 102             <entry>Bochs Emulator</entry>
 103           </row>
 104
 105           <row>
 106             <entry><varname>uml</varname></entry>
 107             <entry>User-mode Linux</entry>
 108           </row>
 109
 110           <row>
 111             <entry><varname>parallels</varname></entry>
 112             <entry>Parallels Desktop, Parallels Server</entry>
 113           </row>
 114
 115           <row>
 116             <entry><varname>bhyve</varname></entry>
 117             <entry>bhyve, FreeBSD hypervisor</entry>
 118           </row>
 119
 120           <row>
 121             <entry><varname>qnx</varname></entry>
 122             <entry>QNX hypervisor</entry>
 123           </row>
 124
 125           <row>
 126             <entry><varname>acrn</varname></entry>
 127             <entry><ulink url="https://projectacrn.org">ACRN hypervisor</ulink></entry>
 128           </row>
 129
 130           <row>
 131             <entry valign="top" morerows="6">Container</entry>
 132             <entry><varname>openvz</varname></entry>
 133             <entry>OpenVZ/Virtuozzo</entry>
 134           </row>
 135
 136           <row>
 137             <entry><varname>lxc</varname></entry>
 138             <entry>Linux container implementation by LXC</entry>
 139           </row>
 140
 141           <row>
 142             <entry><varname>lxc-libvirt</varname></entry>
 143             <entry>Linux container implementation by libvirt</entry>
 144           </row>
 145
 146           <row>
 147             <entry><varname>systemd-nspawn</varname></entry>
 148             <entry>systemd's minimal container implementation, see <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry></entry>
 149           </row>
 150
 151           <row>
 152             <entry><varname>docker</varname></entry>
 153             <entry>Docker container manager</entry>
 154           </row>
 155
 156           <row>
 157             <entry><varname>rkt</varname></entry>
 158             <entry>rkt app container runtime</entry>
 159           </row>
 160
 161           <row>
 162             <entry><varname>wsl</varname></entry>
 163             <entry><ulink url="https://docs.microsoft.com/en-us/windows/wsl/about">Windows Subsystem for Linux</ulink></entry>
 164           </row>
 165         </tbody>
 166       </tgroup>
 167     </table>
 168
 169     <para>If multiple virtualization solutions are used, only the
 170     "innermost" is detected and identified. That means if both
 171     machine and container virtualization are used in
 172     conjunction, only the latter will be identified (unless
 173     <option>--vm</option> is passed).</para>
 174     <para> Windows Subsystem for Linux is not a Linux container,
 175     but an environment for running Linux userspace applications on
 176     top of the Windows kernel using a Linux-compatible interface.
 177     WSL is categorized as a container for practical purposes.
 178     Multiple WSL environments share the same kernel and services
 179     should generally behave like when being run in a container.</para>
 180   </refsect1>
 181
 182   <refsect1>
 183     <title>Options</title>
 184
 185     <para>The following options are understood:</para>
 186
 187     <variablelist>
 188       <varlistentry>
 189         <term><option>-c</option></term>
 190         <term><option>--container</option></term>
 191
 192         <listitem><para>Only detects container virtualization (i.e.
 193         shared kernel virtualization).</para></listitem>
 194       </varlistentry>
 195
 196       <varlistentry>
 197         <term><option>-v</option></term>
 198         <term><option>--vm</option></term>
 199
 200         <listitem><para>Only detects hardware virtualization.</para></listitem>
 201       </varlistentry>
 202
 203       <varlistentry>
 204         <term><option>-r</option></term>
 205         <term><option>--chroot</option></term>
 206
 207         <listitem><para>Detect whether invoked in a
 208         <citerefentry><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 209         environment. In this mode, no output is written, but the return
 210         value indicates whether the process was invoked in a
 211         <function>chroot()</function>
 212         environment or not.</para></listitem>
 213       </varlistentry>
 214
 215       <varlistentry>
 216         <term><option>--private-users</option></term>
 217
 218         <listitem><para>Detect whether invoked in a user namespace.  In this mode, no
 219         output is written, but the return value indicates whether the process was invoked
 220         inside of a user namespace or not. See
 221         <citerefentry project='man-pages'><refentrytitle>user_namespaces</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 222         for more information.</para></listitem>
 223       </varlistentry>
 224
 225       <varlistentry>
 226         <term><option>-q</option></term>
 227         <term><option>--quiet</option></term>
 228
 229         <listitem><para>Suppress output of the virtualization
 230         technology identifier.</para></listitem>
 231       </varlistentry>
 232
 233       <varlistentry>
 234         <term><option>--list</option></term>
 235
 236         <listitem><para>Output all currently known and detectable container and VM environments.</para></listitem>
 237       </varlistentry>
 238
 239       <xi:include href="standard-options.xml" xpointer="help" />
 240       <xi:include href="standard-options.xml" xpointer="version" />
 241     </variablelist>
 242
 243   </refsect1>
 244
 245   <refsect1>
 246     <title>Exit status</title>
 247
 248     <para>If a virtualization technology is detected, 0 is returned, a
 249     non-zero code otherwise.</para>
 250   </refsect1>
 251
 252   <refsect1>
 253     <title>See Also</title>
 254     <para>
 255       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 256       <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 257       <citerefentry><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 258       <citerefentry project='man-pages'><refentrytitle>namespaces</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 259     </para>
 260   </refsect1>
 261
 262 </refentry>