The best aspect of OpenStack is that you can choose to run services as per your requirement. However, there are some basic services that Trove and its features are dependent on; they need to be present:
Neutron is an optional component, and in its absence, the Nova network can provide the basic networking capabilities that are needed.
Keystone, Cinder, and Nova are mandatory, without which the service can't even perform its basic function. In the absence of Swift, the system will provide databases, but the backup/restore and replication/clusters and so on wouldn't work.