The minimum required version of libvirt in the driver is 0.9.11 still [1]. We've been gating against 1.2.2 in Ubuntu Trusty 14.04 since Juno. The libvirt distro support matrix is here: [2] Can we safely assume the people aren't going to be running Libvirt compute nodes on RHEL < 7.1 or Ubuntu Precise? Regarding RHEL, I think this is a safe bet because in Kilo nova dropped python 2.6 support and RHEL > 6 doesn't have py26 so you'd be in trouble running kilo+ nova on RHEL 6.x anyway. There are some workarounds in the code [3] I'd like to see removed by bumping the minimum required version. [1] http://git.openstack.org/cgit/openstack/nova/tree/nova/virt/libvirt/driver.py?id=2015.1.0#n335 [2] https://wiki.openstack.org/wiki/LibvirtDistroSupportMatrix [3] http://git.openstack.org/cgit/openstack/nova/tree/nova/virt/libvirt/host.py?id=2015.1.0#n754 -- Thanks, Matt Riedemann