Hi Armando, I finally got around to reading https://blueprints.launchpad.net/nova/+spec/host-aggregates. Perhaps you could elaborate a little on how this differs from host capabilities (key-value pairs associated with a service) that the scheduler can use when making decisions? The distributed scheduler doesn't need zones to operate, but will use them if available. Would host-aggregates simply be a single-zone that uses capabilities? Cheers, Sandy