Nova

On each controller node running the Nova service, as well as compute node running nova-compute, you must configure Nova to send notifications. These notifications are used by the Infoblox IPAM agent to manage DNS entries and extensible attribute values for VMs.

Set the following values in nova.conf, if they are not already set:
notification_driver = messagingv2
notification_topics = notifications
notify_on_state_change = vm_state