man/systemd-detect-virt.xml

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   6   SPDX-License-Identifier: LGPL-2.1+
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   8
   9 <refentry id="systemd-detect-virt"
  10           xmlns:xi="http://www.w3.org/2001/XInclude">
  11
  12   <refentryinfo>
  13     <title>systemd-detect-virt</title>
  14     <productname>systemd</productname>
  15   </refentryinfo>
  16
  17   <refmeta>
  18     <refentrytitle>systemd-detect-virt</refentrytitle>
  19     <manvolnum>1</manvolnum>
  20   </refmeta>
  21
  22   <refnamediv>
  23     <refname>systemd-detect-virt</refname>
  24     <refpurpose>Detect execution in a virtualized environment</refpurpose>
  25   </refnamediv>
  26
  27   <refsynopsisdiv>
  28     <cmdsynopsis>
  29       <command>systemd-detect-virt</command>
  30       <arg choice="opt" rep="repeat">OPTIONS</arg>
  31     </cmdsynopsis>
  32   </refsynopsisdiv>
  33
  34   <refsect1>
  35     <title>Description</title>
  36
  37     <para><command>systemd-detect-virt</command> detects execution in
  38     a virtualized environment. It identifies the virtualization
  39     technology and can distinguish full machine virtualization from
  40     container virtualization. <filename>systemd-detect-virt</filename>
  41     exits with a return value of 0 (success) if a virtualization
  42     technology is detected, and non-zero (error) otherwise. By default,
  43     any type of virtualization is detected, and the options
  44     <option>--container</option> and <option>--vm</option> can be used
  45     to limit what types of virtualization are detected.</para>
  46
  47     <para>When executed without <option>--quiet</option> will print a
  48     short identifier for the detected virtualization technology. The
  49     following technologies are currently identified:</para>
  50
  51     <table>
  52       <title>Known virtualization technologies (both
  53       VM, i.e. full hardware virtualization,
  54       and container, i.e. shared kernel virtualization)</title>
  55       <tgroup cols='3' align='left' colsep='1' rowsep='1'>
  56         <colspec colname="type" />
  57         <colspec colname="id" />
  58         <colspec colname="product" />
  59         <thead>
  60           <row>
  61             <entry>Type</entry>
  62             <entry>ID</entry>
  63             <entry>Product</entry>
  64           </row>
  65         </thead>
  66         <tbody>
  67           <row>
  68             <entry valign="top" morerows="11">VM</entry>
  69             <entry><varname>qemu</varname></entry>
  70             <entry>QEMU software virtualization, without KVM</entry>
  71           </row>
  72
  73           <row>
  74             <entry><varname>kvm</varname></entry>
  75             <entry>Linux KVM kernel virtual machine, with whatever software, except Oracle Virtualbox</entry>
  76           </row>
  77
  78           <row>
  79             <entry><varname>zvm</varname></entry>
  80             <entry>s390 z/VM</entry>
  81           </row>
  82
  83           <row>
  84             <entry><varname>vmware</varname></entry>
  85             <entry>VMware Workstation or Server, and related products</entry>
  86           </row>
  87
  88           <row>
  89             <entry><varname>microsoft</varname></entry>
  90             <entry>Hyper-V, also known as Viridian or Windows Server Virtualization</entry>
  91           </row>
  92
  93           <row>
  94             <entry><varname>oracle</varname></entry>
  95             <entry>Oracle VM VirtualBox (historically marketed by innotek and Sun Microsystems), for legacy and KVM hypervisor</entry>
  96           </row>
  97
  98           <row>
  99             <entry><varname>xen</varname></entry>
 100             <entry>Xen hypervisor (only domU, not dom0)</entry>
 101           </row>
 102
 103           <row>
 104             <entry><varname>bochs</varname></entry>
 105             <entry>Bochs Emulator</entry>
 106           </row>
 107
 108           <row>
 109             <entry><varname>uml</varname></entry>
 110             <entry>User-mode Linux</entry>
 111           </row>
 112
 113           <row>
 114             <entry><varname>parallels</varname></entry>
 115             <entry>Parallels Desktop, Parallels Server</entry>
 116           </row>
 117
 118           <row>
 119             <entry><varname>bhyve</varname></entry>
 120             <entry>bhyve, FreeBSD hypervisor</entry>
 121           </row>
 122
 123           <row>
 124             <entry><varname>qnx</varname></entry>
 125             <entry>QNX hypervisor</entry>
 126           </row>
 127
 128           <row>
 129             <entry><varname>acrn</varname></entry>
 130             <entry><ulink url="https://projectacrn.org">ACRN hypervisor</ulink></entry>
 131           </row>
 132
 133           <row>
 134             <entry valign="top" morerows="6">Container</entry>
 135             <entry><varname>openvz</varname></entry>
 136             <entry>OpenVZ/Virtuozzo</entry>
 137           </row>
 138
 139           <row>
 140             <entry><varname>lxc</varname></entry>
 141             <entry>Linux container implementation by LXC</entry>
 142           </row>
 143
 144           <row>
 145             <entry><varname>lxc-libvirt</varname></entry>
 146             <entry>Linux container implementation by libvirt</entry>
 147           </row>
 148
 149           <row>
 150             <entry><varname>systemd-nspawn</varname></entry>
 151             <entry>systemd's minimal container implementation, see <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry></entry>
 152           </row>
 153
 154           <row>
 155             <entry><varname>docker</varname></entry>
 156             <entry>Docker container manager</entry>
 157           </row>
 158
 159           <row>
 160             <entry><varname>rkt</varname></entry>
 161             <entry>rkt app container runtime</entry>
 162           </row>
 163
 164           <row>
 165             <entry><varname>wsl</varname></entry>
 166             <entry><ulink url="https://docs.microsoft.com/en-us/windows/wsl/about">Windows Subsystem for Linux</ulink></entry>
 167           </row>
 168         </tbody>
 169       </tgroup>
 170     </table>
 171
 172     <para>If multiple virtualization solutions are used, only the
 173     "innermost" is detected and identified. That means if both
 174     machine and container virtualization are used in
 175     conjunction, only the latter will be identified (unless
 176     <option>--vm</option> is passed).</para>
 177     <para> Windows Subsystem for Linux is not a Linux container,
 178     but an environment for running Linux userspace applications on
 179     top of the Windows kernel using a Linux-compatible interface.
 180     WSL is categorized as a container for practical purposes.
 181     Multiple WSL environments share the same kernel and services
 182     should generally behave like when being run in a container.</para>
 183   </refsect1>
 184
 185   <refsect1>
 186     <title>Options</title>
 187
 188     <para>The following options are understood:</para>
 189
 190     <variablelist>
 191       <varlistentry>
 192         <term><option>-c</option></term>
 193         <term><option>--container</option></term>
 194
 195         <listitem><para>Only detects container virtualization (i.e.
 196         shared kernel virtualization).</para></listitem>
 197       </varlistentry>
 198
 199       <varlistentry>
 200         <term><option>-v</option></term>
 201         <term><option>--vm</option></term>
 202
 203         <listitem><para>Only detects hardware virtualization.</para></listitem>
 204       </varlistentry>
 205
 206       <varlistentry>
 207         <term><option>-r</option></term>
 208         <term><option>--chroot</option></term>
 209
 210         <listitem><para>Detect whether invoked in a
 211         <citerefentry><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 212         environment. In this mode, no output is written, but the return
 213         value indicates whether the process was invoked in a
 214         <function>chroot()</function>
 215         environment or not.</para></listitem>
 216       </varlistentry>
 217
 218       <varlistentry>
 219         <term><option>--private-users</option></term>
 220
 221         <listitem><para>Detect whether invoked in a user namespace.  In this mode, no
 222         output is written, but the return value indicates whether the process was invoked
 223         inside of a user namespace or not. See
 224         <citerefentry project='man-pages'><refentrytitle>user_namespaces</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 225         for more information.</para></listitem>
 226       </varlistentry>
 227
 228       <varlistentry>
 229         <term><option>-q</option></term>
 230         <term><option>--quiet</option></term>
 231
 232         <listitem><para>Suppress output of the virtualization
 233         technology identifier.</para></listitem>
 234       </varlistentry>
 235
 236       <varlistentry>
 237         <term><option>--list</option></term>
 238
 239         <listitem><para>Output all currently known and detectable container and VM environments.</para></listitem>
 240       </varlistentry>
 241
 242       <xi:include href="standard-options.xml" xpointer="help" />
 243       <xi:include href="standard-options.xml" xpointer="version" />
 244     </variablelist>
 245
 246   </refsect1>
 247
 248   <refsect1>
 249     <title>Exit status</title>
 250
 251     <para>If a virtualization technology is detected, 0 is returned, a
 252     non-zero code otherwise.</para>
 253   </refsect1>
 254
 255   <refsect1>
 256     <title>See Also</title>
 257     <para>
 258       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 259       <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 260       <citerefentry><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 261       <citerefentry project='man-pages'><refentrytitle>namespaces</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 262     </para>
 263   </refsect1>
 264
 265 </refentry>