When you want to make use of event based meters (like
vcpus) in your OpenStack Nova installation, make sure that the Nova compute service is telemetry enabled, i.e. its
[DEFAULT] ... instance_usage_audit = True instance_usage_audit_period = hour notify_on_state_change = vm_and_task_state notification_driver = messagingv2
After performing this change you’ll have to restart the Ceilometer compute agent (which you can run with the
ceilometer-polling --polling-namespaces compute command, by the way) and the Nova compute service.
Always true to form, I probabably forgot this simple configuration step for 5 or 10 times now and have built several widow’s walks while waiting for those elusive
Relevant documentation: OpenStack Installation Guide for Ubuntu