There are several ways to keep an eye on and watch what is going on in your OpenStack private cloud. We have already hacked Ceilometer as an official monitoring service well integrated into OpenStack. It might be a very fruitful solution to facilitate customer billing as well. You have noticed already how Ceilometer can even watch customer instances that we have deployed in a sample example via HOT. Although the former telemetry module is expanding its metrics to cover the image, block and object storage, and network service, it might be necessary to bring in your more mature infrastructure monitoring tools for additional alerting. Zabbix is one of the greatest tools that keeps an eye on our OpenStack environment.