NAME¶
virt-what - detect if we are running in a virtual machine
SUMMARY¶
virt-what [options]
DESCRIPTION¶
"virt-what" is a shell script which can be used to detect if the
program is running in a virtual machine.
The program prints out a list of "facts" about the virtual machine,
derived from heuristics. One fact is printed per line.
If nothing is printed and the script exits with code 0 (no error), then it can
mean
either that the program is running on bare-metal
or the
program is running inside a type of virtual machine which we don't know about
or cannot detect.
FACTS¶
- hyperv
- This is Microsoft Hyper-V hypervisor.
Status: confirmed by RWMJ
- ibm_systemz
- This is an IBM SystemZ (or other S/390) hardware
partitioning system. Additional facts listed below may also be
printed.
- ibm_systemz-direct
- This is Linux running directly on a IBM SystemZ hardware
partitioning system.
This is expected to be a highly unusual configuration - if you see this
result you should treat it with suspicion.
Status: not confirmed
- ibm_systemz-lpar
- This is Linux running directly on an LPAR on an IBM SystemZ
hardware partitioning system.
Status: not confirmed
- ibm_systemz-zvm
- This is a z/VM guest running in an LPAR on an IBM SystemZ
hardware partitioning system.
Status: confirmed by RWMJ using a Fedora guest running in z/VM
- linux_vserver
- This process is running in a Linux VServer container.
Status: contributed by BarXX Metin
- kvm
- This guest is running on the KVM hypervisor using hardware
acceleration.
Note that if the hypervisor is using software acceleration you should
not see this, but should see the "qemu" fact instead.
Status: confirmed by RWMJ.
- openvz
- The guest appears to be running inside an OpenVZ or
Virtuozzo container.
Status: contributed by Evgeniy Sokolov
- parallels
- The guest is running inside Parallels Virtual Platform
(Parallels Desktop, Parallels Server).
Status: contributed by Justin Clift
- powervm_lx86
- The guest is running inside IBM PowerVM Lx86 Linux/x86
emulator.
Status: data originally supplied by Jeffrey Scheel, confimed by Yufang Zhang
and RWMJ
- qemu
- This is QEMU hypervisor using software emulation.
Note that for KVM (hardware accelerated) guests you should not see
this.
Status: confirmed by RWMJ.
- uml
- This is a User-Mode Linux (UML) guest.
Status: contributed by Laurent Leonard
- virt
- Some sort of virtualization appears to be present, but we
are not sure what it is. In some very rare corner cases where we know that
virtualization is hard to detect, we will try a timing attack to see if
certain machine instructions are running much more slowly than they should
be, which would indicate virtualization. In this case, the generic fact
"virt" is printed.
- virtage
- This is Hitachi Virtualization Manager (HVM) Virtage
hardware partitioning system.
Status: data supplied by Bhavna Sarathy, not confirmed
- virtualbox
- This is a VirtualBox guest.
Status: contributed by Laurent Leonard
- virtualpc
- The guest appears to be running on Microsoft VirtualPC.
Status: not confirmed
- vmware
- The guest appears to be running on VMware hypervisor.
Status: confirmed by RWMJ
- xen
- The guest appears to be running on Xen hypervisor.
Status: confirmed by RWMJ
- xen-dom0
- This is the Xen dom0 (privileged domain).
Status: confirmed by RWMJ
- xen-domU
- This is a Xen domU (paravirtualized guest domain).
Status: confirmed by RWMJ
- xen-hvm
- This is a Xen guest fully virtualized (HVM).
Status: confirmed by RWMJ
EXIT STATUS¶
Programs that use or wrap "virt-what" should check that the exit
status is 0 before they attempt to parse the output of the command.
A non-zero exit status indicates some error, for example, an unrecognized
command line argument. If the exit status is non-zero then the output
"facts" (if any were printed) cannot be guaranteed and should be
ignored.
The exit status does
not have anything to do with whether the program is
running on baremetal or under virtualization, nor with whether
"virt-what" managed detection "correctly" (which is
basically unknowable given the large variety of virtualization systems out
there and that some systems deliberately emulate others).
RUNNING VIRT-WHAT FROM OTHER PROGRAMS¶
"virt-what" is designed so that you can easily run it from other
programs or wrap it up in a library.
Your program should check the exit status (see the section above).
Some programming languages (notably Python: issue 1652) erroneously mask the
"SIGPIPE" signal and do not restore it when executing subprocesses.
"virt-what" is a shell script and some shell commands do not work
correctly when you do this. You may see warnings from "virt-what"
similar to this:
echo: write error: Broken pipe
The solution is to set the "SIGPIPE" signal handler back to
"SIG_DFL" before running "virt-what".
IMPORTANT NOTE¶
Most of the time, using this program is the
wrong thing to do. Instead
you should detect the specific features you actually want to use. (As an
example, if you wanted to issue Xen hypervisor commands you would look for the
"/proc/xen/privcmd" file).
However people keep asking for this, so we provide it. There are a few
legitimate uses:
- Bug reporting tool
- If you think that virtualization could affect how your
program runs, then you might use "virt-what" to report this in a
bug reporting tool.
- Status display and monitoring tools
- You might include this information in status and monitoring
programs.
SEE ALSO¶
http://people.redhat.com/~rjones/virt-what/
<
http://people.redhat.com/~rjones/virt-what/>,
<
http://www.vmware.com/>,
<
http://www.microsoft.com/windows/products/winfamily/virtualpc>,
<
http://xensource.com/>, <
http://bellard.org/qemu/>,
<
http://kvm.qumranet.com/>, <
http://openvz.org/>
AUTHORS¶
Richard W.M. Jones <rjones @ redhat . com>
COPYRIGHT¶
(C) Copyright 2008-2011 Red Hat Inc.,
http://people.redhat.com/~rjones/virt-what/
<
http://people.redhat.com/~rjones/virt-what/>
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 675 Mass
Ave, Cambridge, MA 02139, USA.
REPORTING BUGS¶
Bugs can be viewed on the Red Hat Bugzilla page:
<
https://bugzilla.redhat.com/>.
If you find a bug in virt-what, please follow these steps to report it:
- 1. Check for existing bug reports
- Go to <https://bugzilla.redhat.com/> and search for
similar bugs. Someone may already have reported the same bug, and they may
even have fixed it.
- 2. Capture debug and error messages
- Run
virt-what > virt-what.log 2>&1
and keep virt-what.log. It may contain error messages which you
should submit with your bug report.
- 3. Get version of virt-what.
- Run
virt-what --version
- 4. Submit a bug report.
- Go to <https://bugzilla.redhat.com/> and enter a new
bug. Please describe the problem in as much detail as possible.
Remember to include the version numbers (step 3) and the debug messages file
(step 2) and as much other detail as possible.
- 5. Assign the bug to rjones @ redhat.com
- Assign or reassign the bug to rjones @ redhat.com
(without the spaces). You can also send me an email with the bug number if
you want a faster response.