`nova-billing` service is ready for community review. It is a service which accounts resource usage per project (tenant). This information can be used for charging client later.
Currently it collects information about instances and images and snapshost in glance. Local disk usage (Gb*h), memory (Mb*h) and virtual CPU count (vcpus*h) are accounted for VM instances and disk space (Gb*h) is accounted for images in glance .
Next we are going to include other resources like network storages (volumes).