5 virt-what - detect if we are running in a virtual machine
13 C<virt-what> is a shell script which can be used to detect if the
14 program is running in a virtual machine.
16 The program prints out a list of "facts" about the virtual machine,
17 derived from heuristics. One fact is printed per line.
19 If nothing is printed and the script exits with code 0 (no error),
20 then it can mean I<either> that the program is running on bare-metal
21 I<or> the program is running inside a type of virtual machine which we
22 don't know about or cannot detect.
30 This is Microsoft Hyper-V hypervisor.
32 Status: confirmed by RWMJ
36 This is an IBM SystemZ (or other S/390) hardware partitioning system.
37 Additional facts listed below may also be printed.
39 =item B<ibm_systemz-direct>
41 This is Linux running directly on a IBM SystemZ hardware partitioning
44 This is expected to be a highly unusual configuration - if
45 you see this result you should treat it with suspicion.
49 =item B<ibm_systemz-lpar>
51 This is Linux running directly on an LPAR on an IBM SystemZ
52 hardware partitioning system.
56 =item B<ibm_systemz-zvm>
58 This is a z/VM guest running in an LPAR on an IBM SystemZ
59 hardware partitioning system.
61 Status: confirmed by RWMJ using a Fedora guest running in z/VM
63 =item B<linux_vserver>
65 This process is running in a Linux VServer container.
67 Status: contributed by Barış Metin
71 This process is running in a Linux LXC container.
73 Status: contributed by Marc Fournier
77 This guest is running on the KVM hypervisor using hardware
80 Note that if the hypervisor is using software acceleration
81 you should I<not> see this, but should see the C<qemu> fact
84 Status: confirmed by RWMJ.
88 The guest appears to be running inside an OpenVZ or Virtuozzo
91 Status: contributed by Evgeniy Sokolov
95 The guest is running inside Parallels Virtual Platform
96 (Parallels Desktop, Parallels Server).
98 Status: contributed by Justin Clift
100 =item B<powervm_lx86>
102 The guest is running inside IBM PowerVM Lx86 Linux/x86 emulator.
104 Status: data originally supplied by Jeffrey Scheel, confimed by
105 Yufang Zhang and RWMJ
109 This is QEMU hypervisor using software emulation.
111 Note that for KVM (hardware accelerated) guests you should I<not> see
114 Status: confirmed by RWMJ.
118 This is a User-Mode Linux (UML) guest.
120 Status: contributed by Laurent Léonard
124 Some sort of virtualization appears to be present, but we are not sure
125 what it is. In some very rare corner cases where we know that
126 virtualization is hard to detect, we will try a timing attack to see
127 if certain machine instructions are running much more slowly than they
128 should be, which would indicate virtualization. In this case, the
129 generic fact C<virt> is printed.
133 This is Hitachi Virtualization Manager (HVM) Virtage
134 hardware partitioning system.
136 Status: data supplied by Bhavna Sarathy, not confirmed
140 This is a VirtualBox guest.
142 Status: contributed by Laurent Léonard
146 The guest appears to be running on Microsoft VirtualPC.
148 Status: not confirmed
152 The guest appears to be running on VMware hypervisor.
154 Status: confirmed by RWMJ
158 The guest appears to be running on Xen hypervisor.
160 Status: confirmed by RWMJ
164 This is the Xen dom0 (privileged domain).
166 Status: confirmed by RWMJ
170 This is a Xen domU (paravirtualized guest domain).
172 Status: confirmed by RWMJ
176 This is a Xen guest fully virtualized (HVM).
178 Status: confirmed by RWMJ
184 Programs that use or wrap C<virt-what> should check that the exit
185 status is 0 before they attempt to parse the output of the command.
187 A non-zero exit status indicates some error, for example, an
188 unrecognized command line argument. If the exit status is non-zero
189 then the output "facts" (if any were printed) cannot be guaranteed and
192 The exit status does I<not> have anything to do with whether the
193 program is running on baremetal or under virtualization, nor with
194 whether C<virt-what> managed detection "correctly" (which is basically
195 unknowable given the large variety of virtualization systems out there
196 and that some systems deliberately emulate others).
198 =head1 RUNNING VIRT-WHAT FROM OTHER PROGRAMS
200 C<virt-what> is designed so that you can easily run it from
201 other programs or wrap it up in a library.
203 Your program should check the exit status (see the section above).
205 Some programming languages (notably Python: issue 1652) erroneously
206 mask the C<SIGPIPE> signal and do not restore it when executing
207 subprocesses. C<virt-what> is a shell script and some shell commands
208 do not work correctly when you do this. You may see warnings from
209 C<virt-what> similar to this:
211 echo: write error: Broken pipe
213 The solution is to set the C<SIGPIPE> signal handler back to C<SIG_DFL>
214 before running C<virt-what>.
216 =head1 IMPORTANT NOTE
218 Most of the time, using this program is the I<wrong> thing to do.
219 Instead you should detect the specific features you actually want to
220 use. (As an example, if you wanted to issue Xen hypervisor commands
221 you would look for the C</proc/xen/privcmd> file).
223 However people keep asking for this, so we provide it. There are a
228 =item Bug reporting tool
230 If you think that virtualization could affect how your program runs,
231 then you might use C<virt-what> to report this in a bug reporting
234 =item Status display and monitoring tools
236 You might include this information in status and monitoring programs.
238 =item System tuning (sometimes)
240 You might use this program to tune an operating system so it runs
241 better as a virtual machine of a particular hypervisor. However if
242 installing paravirtualized drivers, it's better to check for the
243 specific features your drivers need (eg. for the presence of PCI devices).
249 L<http://people.redhat.com/~rjones/virt-what/>,
250 L<http://www.vmware.com/>,
251 L<http://www.microsoft.com/windows/products/winfamily/virtualpc>,
252 L<http://xensource.com/>,
253 L<http://bellard.org/qemu/>,
254 L<http://kvm.qumranet.com/>,
255 L<http://openvz.org/>
259 Richard W.M. Jones <rjones @ redhat . com>
263 (C) Copyright 2008-2011 Red Hat Inc.,
264 L<http://people.redhat.com/~rjones/virt-what/>
266 This program is free software; you can redistribute it and/or modify
267 it under the terms of the GNU General Public License as published by
268 the Free Software Foundation; either version 2 of the License, or
269 (at your option) any later version.
271 This program is distributed in the hope that it will be useful,
272 but WITHOUT ANY WARRANTY; without even the implied warranty of
273 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
274 GNU General Public License for more details.
276 You should have received a copy of the GNU General Public License
277 along with this program; if not, write to the Free Software
278 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
280 =head1 REPORTING BUGS
282 Bugs can be viewed on the Red Hat Bugzilla page:
283 L<https://bugzilla.redhat.com/>.
285 If you find a bug in virt-what, please follow these steps to report it:
289 =item 1. Check for existing bug reports
291 Go to L<https://bugzilla.redhat.com/> and search for similar bugs.
292 Someone may already have reported the same bug, and they may even
295 =item 2. Capture debug and error messages
299 virt-what > virt-what.log 2>&1
301 and keep I<virt-what.log>. It may contain error messages which you
302 should submit with your bug report.
304 =item 3. Get version of virt-what.
310 =item 4. Submit a bug report.
312 Go to L<https://bugzilla.redhat.com/> and enter a new bug.
313 Please describe the problem in as much detail as possible.
315 Remember to include the version numbers (step 3) and the debug
316 messages file (step 2) and as much other detail as possible.
318 =item 5. Assign the bug to rjones @ redhat.com
320 Assign or reassign the bug to B<rjones @ redhat.com> (without the
321 spaces). You can also send me an email with the bug number if you
322 want a faster response.