A fellow measurement and alarm fan! Nice to meet you, Mohsen.
You hit exactly the problem that made me investigate Gnocchi. There is no cpu_util anymore; the release notes say that you can use Gnocchi’s rate features to create it. And yes, it works, but: Aodh uses an old API to acquire measurements. I have not found a way to create alarms on CPU utilization, therefore I have no idea how to implement autoscaling based on CPU usage.
My feeling is that the three teams Ceilometer, Aodh and Heat are not in synch regarding this problem. Most probably it has not become a real-world problem yet, because no production cloud uses Stein. I am convinced that this will change at some point, and they will solve this, probably by updating Aodh.
I raised two bugs, but it doesn’t look like anybody has picked them up yet: