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