[Libguestfs] guestfish/libguestfs takes legacy qemu instead of kvm?

Kirby Zhou kirbyzhou at sohu-rd.com
Tue Aug 10 09:27:56 UTC 2010

Thanks very much.
BTW, I have a small question, why libguestfs depends on QEMU instead of
If we take libvirt, we can easily run libguestfs with xen, virtualbox,
vmware, etc.

   Kirby Zhou    
   from   SOHU-RD   +86-10-6272-8261

-----Original Message-----
From: libguestfs-bounces at redhat.com [mailto:libguestfs-bounces at redhat.com]
On Behalf Of Richard W.M. Jones
Sent: Sunday, August 08, 2010 7:26 PM
To: EPEL development disccusion
Cc: libguestfs at redhat.com
Subject: Re: [Libguestfs] guestfish/libguestfs takes legacy qemu instead of

On Sun, Aug 08, 2010 at 12:05:58PM +0800, Kirby Zhou wrote:
> guestfish takes legacy qemu instead of kvm?
> ]# rpm -q libguestfs --requires | fgrep qemu
> qemu-system-x86 >= 0.10.5

To make it clear, this is EPEL-5.  There was some still unresolved
problem with adding a dependency on KVM:


As a result, we have to depend on qemu (software emulation) instead.
However you can easily change this at runtime by setting the
LIBGUESTFS_QEMU environment variable:


In RHEL 6 it's all going to be different again.  The same
qemu-system-x86 RPM is actually KVM.  We combine qemu and KVM sources
during the build to make a 'qemu-kvm' binary which can do both
software emulation (TCG) and hardware virt (KVM).

> [@djt_10_48 ~]# guestfish -i kvm-rhel5guest 
> Could not open '/dev/kqemu' - QEMU acceleration layer not activated: No
> file or directory

This is just a warning -- ignore it.


Richard Jones, Virtualization Group, Red Hat
virt-df lists disk usage of guests without needing to install any
software inside the virtual machine.  Supports Linux and Windows.

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