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 a Docker container.
32 Status: confirmed by Charles Nguyen
36 This is Microsoft Hyper-V hypervisor.
38 Status: confirmed by RWMJ
42 This is an IBM SystemZ (or other S/390) hardware partitioning system.
43 Additional facts listed below may also be printed.
45 =item B<ibm_systemz-direct>
47 This is Linux running directly on a IBM SystemZ hardware partitioning
50 This is expected to be a highly unusual configuration - if
51 you see this result you should treat it with suspicion.
55 =item B<ibm_systemz-lpar>
57 This is Linux running directly on an LPAR on an IBM SystemZ
58 hardware partitioning system.
62 =item B<ibm_systemz-zvm>
64 This is a z/VM guest running in an LPAR on an IBM SystemZ
65 hardware partitioning system.
67 Status: confirmed by RWMJ using a Fedora guest running in z/VM
69 =item B<linux_vserver>
71 This is printed for backwards compatibility with older virt-what which
72 could not distinguish between a Linux VServer container guest and
75 =item B<linux_vserver-guest>
77 This process is running in a Linux VServer container.
79 Status: contributed by Barış Metin
81 =item B<linux_vserver-host>
83 This process is running as the Linux VServer host (VxID 0).
85 Status: contributed by Barış Metin and Elan Ruusamäe
89 This process is running in a Linux LXC container.
91 Status: contributed by Marc Fournier
95 This guest is running on the KVM hypervisor using hardware
98 Note that if the hypervisor is using software acceleration
99 you should I<not> see this, but should see the C<qemu> fact
102 Status: confirmed by RWMJ.
106 This guest is running on the KVM hypervisor using hardware
107 acceleration, and the userspace component of the hypervisor
108 is lkvm (a.k.a kvmtool).
110 Status: contributed by Andrew Jones
114 The guest appears to be running inside an OpenVZ or Virtuozzo
117 Status: contributed by Evgeniy Sokolov
121 The guest is running on an oVirt or RHEV node.
123 Status: contributed by RWMJ, not confirmed
127 The guest is running inside Parallels Virtual Platform
128 (Parallels Desktop, Parallels Server).
130 Status: contributed by Justin Clift
132 =item B<powervm_lx86>
134 The guest is running inside IBM PowerVM Lx86 Linux/x86 emulator.
136 Status: data originally supplied by Jeffrey Scheel, confirmed by
137 Yufang Zhang and RWMJ
141 This is QEMU hypervisor using software emulation.
143 Note that for KVM (hardware accelerated) guests you should I<not> see
146 Status: confirmed by RWMJ.
150 This is a User-Mode Linux (UML) guest.
152 Status: contributed by Laurent Léonard
156 Some sort of virtualization appears to be present, but we are not sure
157 what it is. In some very rare corner cases where we know that
158 virtualization is hard to detect, we will try a timing attack to see
159 if certain machine instructions are running much more slowly than they
160 should be, which would indicate virtualization. In this case, the
161 generic fact C<virt> is printed.
165 This is Hitachi Virtualization Manager (HVM) Virtage
166 hardware partitioning system.
168 Status: data supplied by Bhavna Sarathy, not confirmed
172 This is a VirtualBox guest.
174 Status: contributed by Laurent Léonard
178 The guest appears to be running on Microsoft VirtualPC.
180 Status: not confirmed
184 The guest appears to be running on VMware hypervisor.
186 Status: confirmed by RWMJ
190 The guest appears to be running on Xen hypervisor.
192 Status: confirmed by RWMJ
196 This is the Xen dom0 (privileged domain).
198 Status: confirmed by RWMJ
202 This is a Xen domU (paravirtualized guest domain).
204 Status: confirmed by RWMJ
208 This is a Xen guest fully virtualized (HVM).
210 Status: confirmed by RWMJ
216 Programs that use or wrap C<virt-what> should check that the exit
217 status is 0 before they attempt to parse the output of the command.
219 A non-zero exit status indicates some error, for example, an
220 unrecognized command line argument. If the exit status is non-zero
221 then the output "facts" (if any were printed) cannot be guaranteed and
224 The exit status does I<not> have anything to do with whether the
225 program is running on baremetal or under virtualization, nor with
226 whether C<virt-what> managed detection "correctly" (which is basically
227 unknowable given the large variety of virtualization systems out there
228 and that some systems deliberately emulate others).
230 =head1 RUNNING VIRT-WHAT FROM OTHER PROGRAMS
232 C<virt-what> is designed so that you can easily run it from
233 other programs or wrap it up in a library.
235 Your program should check the exit status (see the section above).
237 Some programming languages (notably Python: issue 1652) erroneously
238 mask the C<SIGPIPE> signal and do not restore it when executing
239 subprocesses. C<virt-what> is a shell script and some shell commands
240 do not work correctly when you do this. You may see warnings from
241 C<virt-what> similar to this:
243 echo: write error: Broken pipe
245 The solution is to set the C<SIGPIPE> signal handler back to C<SIG_DFL>
246 before running C<virt-what>.
248 =head1 IMPORTANT NOTE
250 Most of the time, using this program is the I<wrong> thing to do.
251 Instead you should detect the specific features you actually want to
252 use. (As an example, if you wanted to issue Xen hypervisor commands
253 you would look for the C</proc/xen/privcmd> file).
255 However people keep asking for this, so we provide it. There are a
260 =item Bug reporting tool
262 If you think that virtualization could affect how your program runs,
263 then you might use C<virt-what> to report this in a bug reporting
266 =item Status display and monitoring tools
268 You might include this information in status and monitoring programs.
270 =item System tuning (sometimes)
272 You might use this program to tune an operating system so it runs
273 better as a virtual machine of a particular hypervisor. However if
274 installing paravirtualized drivers, it's better to check for the
275 specific features your drivers need (eg. for the presence of PCI devices).
281 L<http://people.redhat.com/~rjones/virt-what/>,
282 L<http://www.vmware.com/>,
283 L<http://www.microsoft.com/windows/products/winfamily/virtualpc>,
284 L<http://xensource.com/>,
285 L<http://bellard.org/qemu/>,
286 L<http://kvm.qumranet.com/>,
287 L<http://openvz.org/>
291 Richard W.M. Jones <rjones @ redhat . com>
295 (C) Copyright 2008-2015 Red Hat Inc.,
296 L<http://people.redhat.com/~rjones/virt-what/>
298 This program is free software; you can redistribute it and/or modify
299 it under the terms of the GNU General Public License as published by
300 the Free Software Foundation; either version 2 of the License, or
301 (at your option) any later version.
303 This program is distributed in the hope that it will be useful,
304 but WITHOUT ANY WARRANTY; without even the implied warranty of
305 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
306 GNU General Public License for more details.
308 You should have received a copy of the GNU General Public License
309 along with this program; if not, write to the Free Software
310 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
312 =head1 REPORTING BUGS
314 Bugs can be viewed on the Red Hat Bugzilla page:
315 L<https://bugzilla.redhat.com/>.
317 If you find a bug in virt-what, please follow these steps to report it:
321 =item 1. Check for existing bug reports
323 Go to L<https://bugzilla.redhat.com/> and search for similar bugs.
324 Someone may already have reported the same bug, and they may even
327 =item 2. Capture debug and error messages
331 virt-what > virt-what.log 2>&1
333 and keep I<virt-what.log>. It may contain error messages which you
334 should submit with your bug report.
336 =item 3. Get version of virt-what.
342 =item 4. Submit a bug report.
344 Go to L<https://bugzilla.redhat.com/> and enter a new bug.
345 Please describe the problem in as much detail as possible.
347 Remember to include the version numbers (step 3) and the debug
348 messages file (step 2) and as much other detail as possible.
350 =item 5. Assign the bug to rjones @ redhat.com
352 Assign or reassign the bug to B<rjones @ redhat.com> (without the
353 spaces). You can also send me an email with the bug number if you
354 want a faster response.