Hypervisor Power Management

All hypervisors are always powered on and consumes power irrespective of load on them. Even if there are no instances (VMs) running on a hypervisor, it will still consume power leading to wastage of power costs. This blueprint aims to provide a mechanism to check if there are any unused hypervisors and power off them using custom hypervisor power driver. This helps in saving power consumption costs. Whenever required, nova-scheduler will call the driver this hypervisor power driver to power on the hypervisor without any manual involvement.