Comment 0 for bug 1297528

http://openstack-in-production.blogspot.com/2014/03/cern-cloud-architectut%20re-update-for.html

Every instance of compute-agent calls nova-api meaning the number of background API calls will grow linearly with the number of compute nodes. This additional load is so big that cern had to redesign there cloud to turn ceilometer compute-agent on.