We had a issue in one of the virtualizor node
Where the server on rebooting the KVM VM were not starting
With error message being
error: Failed to create domain from /etc/libvirt/qemu/
error: Cannot get interface MTU on ‘viifbr0’: No such device
ON checking around found the issue with virtnetwork
Below command fixed the issue
service virtnetwork start
~]# service virtnetwork start
Bringing up viifbr0 – OK
Waiting for 10 seconds…1…2…3…4…5…6…7…8…9…10
Internet connectivity check successful viifbr0 – OK