I am building a private cloud.Everything is ok. But I cannot find a way to balance vm when It have heavy load which cause impact other vm on the compute node. I found  solutions such as Watcher and Leveller. But they need to be done manually. Watcher is not good because It need cpu metric such as cpu load in Ceilometer which is removed so we cannot use it. Leveller is good, but It is obsolete.  
Nguyen Huu Khoi