[libvirt-users] unknown driver format value 'qcow3'

[Eric Blake]

On 04/15/2015 08:13 AM, Jatin Davey wrote:
> Hi All
> 
> I am trying to deploy VMs using libvirt and a domainXML file where i
> mention the parameters for the VM to be deployed.
> 
> I am using libvirt version: libvirt 0.10.2

[I'm guessing that you are using something based on RHEL 6, based on how
old that version number is...]

This version of libvirt does not know how to handle qcow2v3 files.  qemu
started creating these by default around qemu 2.0 or so, but you can
still manually create older qcow2v2 files by specifying:

qemu-img create -o compat=0.10 -f qcow2 ...

whenever you are manually creating images.

> 
> Do i need to upgrade to any specific version of libvirt ? or change any
> file to make this work ?

With new enough qemu-img, you can also downgrade an image in-place:

qemu-img convert -f qcow2 -o compat=0.10 file

Or, as you guessed, you can upgrade to newer libvirt that understands
the newer format.  [For example, basing your distro on RHEL 7, even if
you choose to use CentOS instead of RHEL, is a way to get new-enough
libvirt]

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org