[CentOS] upgrading Centos-Xen when version 6 comes along

[Gabriel Tabares]

> Also, if you assign MACs to your VMs at installation time (I do, for
> DHCP- and DNS-related reasons), you should note that KVM MACs lives in
> a different namespace: 54:52:00:xx:xx:xx.

You can change the allocated MAC address by editing the files in 
/etc/libvirt/qemu .

Edit the <mac address='54:52:00:19:f2:ef'/> section and you're all set.

I am not sure if you need to restart libvirtd after making the changes, 
as I have not got a machine I can test that at the moment.