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 is printed for backwards compatibility with older virt-what which
66 could not distinguish between a Linux VServer container guest and
69 =item B<linux_vserver-guest>
71 This process is running in a Linux VServer container.
73 Status: contributed by Barış Metin
75 =item B<linux_vserver-host>
77 This process is running as the Linux VServer host (VxID 0).
79 Status: contributed by Barış Metin and Elan Ruusamäe
83 This process is running in a Linux LXC container.
85 Status: contributed by Marc Fournier
89 This guest is running on the KVM hypervisor using hardware
92 Note that if the hypervisor is using software acceleration
93 you should I<not> see this, but should see the C<qemu> fact
96 Status: confirmed by RWMJ.
100 The guest appears to be running inside an OpenVZ or Virtuozzo
103 Status: contributed by Evgeniy Sokolov
107 The guest is running inside Parallels Virtual Platform
108 (Parallels Desktop, Parallels Server).
110 Status: contributed by Justin Clift
112 =item B<powervm_lx86>
114 The guest is running inside IBM PowerVM Lx86 Linux/x86 emulator.
116 Status: data originally supplied by Jeffrey Scheel, confirmed by
117 Yufang Zhang and RWMJ
121 This is QEMU hypervisor using software emulation.
123 Note that for KVM (hardware accelerated) guests you should I<not> see
126 Status: confirmed by RWMJ.
130 This is a User-Mode Linux (UML) guest.
132 Status: contributed by Laurent Léonard
136 Some sort of virtualization appears to be present, but we are not sure
137 what it is. In some very rare corner cases where we know that
138 virtualization is hard to detect, we will try a timing attack to see
139 if certain machine instructions are running much more slowly than they
140 should be, which would indicate virtualization. In this case, the
141 generic fact C<virt> is printed.
145 This is Hitachi Virtualization Manager (HVM) Virtage
146 hardware partitioning system.
148 Status: data supplied by Bhavna Sarathy, not confirmed
152 This is a VirtualBox guest.
154 Status: contributed by Laurent Léonard
158 The guest appears to be running on Microsoft VirtualPC.
160 Status: not confirmed
164 The guest appears to be running on VMware hypervisor.
166 Status: confirmed by RWMJ
170 The guest appears to be running on Xen hypervisor.
172 Status: confirmed by RWMJ
176 This is the Xen dom0 (privileged domain).
178 Status: confirmed by RWMJ
182 This is a Xen domU (paravirtualized guest domain).
184 Status: confirmed by RWMJ
188 This is a Xen guest fully virtualized (HVM).
190 Status: confirmed by RWMJ
196 Programs that use or wrap C<virt-what> should check that the exit
197 status is 0 before they attempt to parse the output of the command.
199 A non-zero exit status indicates some error, for example, an
200 unrecognized command line argument. If the exit status is non-zero
201 then the output "facts" (if any were printed) cannot be guaranteed and
204 The exit status does I<not> have anything to do with whether the
205 program is running on baremetal or under virtualization, nor with
206 whether C<virt-what> managed detection "correctly" (which is basically
207 unknowable given the large variety of virtualization systems out there
208 and that some systems deliberately emulate others).
210 =head1 RUNNING VIRT-WHAT FROM OTHER PROGRAMS
212 C<virt-what> is designed so that you can easily run it from
213 other programs or wrap it up in a library.
215 Your program should check the exit status (see the section above).
217 Some programming languages (notably Python: issue 1652) erroneously
218 mask the C<SIGPIPE> signal and do not restore it when executing
219 subprocesses. C<virt-what> is a shell script and some shell commands
220 do not work correctly when you do this. You may see warnings from
221 C<virt-what> similar to this:
223 echo: write error: Broken pipe
225 The solution is to set the C<SIGPIPE> signal handler back to C<SIG_DFL>
226 before running C<virt-what>.
228 =head1 IMPORTANT NOTE
230 Most of the time, using this program is the I<wrong> thing to do.
231 Instead you should detect the specific features you actually want to
232 use. (As an example, if you wanted to issue Xen hypervisor commands
233 you would look for the C</proc/xen/privcmd> file).
235 However people keep asking for this, so we provide it. There are a
240 =item Bug reporting tool
242 If you think that virtualization could affect how your program runs,
243 then you might use C<virt-what> to report this in a bug reporting
246 =item Status display and monitoring tools
248 You might include this information in status and monitoring programs.
250 =item System tuning (sometimes)
252 You might use this program to tune an operating system so it runs
253 better as a virtual machine of a particular hypervisor. However if
254 installing paravirtualized drivers, it's better to check for the
255 specific features your drivers need (eg. for the presence of PCI devices).
261 L<http://people.redhat.com/~rjones/virt-what/>,
262 L<http://www.vmware.com/>,
263 L<http://www.microsoft.com/windows/products/winfamily/virtualpc>,
264 L<http://xensource.com/>,
265 L<http://bellard.org/qemu/>,
266 L<http://kvm.qumranet.com/>,
267 L<http://openvz.org/>
271 Richard W.M. Jones <rjones @ redhat . com>
275 (C) Copyright 2008-2011 Red Hat Inc.,
276 L<http://people.redhat.com/~rjones/virt-what/>
278 This program is free software; you can redistribute it and/or modify
279 it under the terms of the GNU General Public License as published by
280 the Free Software Foundation; either version 2 of the License, or
281 (at your option) any later version.
283 This program is distributed in the hope that it will be useful,
284 but WITHOUT ANY WARRANTY; without even the implied warranty of
285 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
286 GNU General Public License for more details.
288 You should have received a copy of the GNU General Public License
289 along with this program; if not, write to the Free Software
290 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
292 =head1 REPORTING BUGS
294 Bugs can be viewed on the Red Hat Bugzilla page:
295 L<https://bugzilla.redhat.com/>.
297 If you find a bug in virt-what, please follow these steps to report it:
301 =item 1. Check for existing bug reports
303 Go to L<https://bugzilla.redhat.com/> and search for similar bugs.
304 Someone may already have reported the same bug, and they may even
307 =item 2. Capture debug and error messages
311 virt-what > virt-what.log 2>&1
313 and keep I<virt-what.log>. It may contain error messages which you
314 should submit with your bug report.
316 =item 3. Get version of virt-what.
322 =item 4. Submit a bug report.
324 Go to L<https://bugzilla.redhat.com/> and enter a new bug.
325 Please describe the problem in as much detail as possible.
327 Remember to include the version numbers (step 3) and the debug
328 messages file (step 2) and as much other detail as possible.
330 =item 5. Assign the bug to rjones @ redhat.com
332 Assign or reassign the bug to B<rjones @ redhat.com> (without the
333 spaces). You can also send me an email with the bug number if you
334 want a faster response.