A UEC system includes physical machines running the following services:
eucalyptus-cloud - includes the front-end services, Cloud Controller
eucalyptus-cc - includes the Cluster Controller that provides support for the virtual network overlay
eucalyptus-sc - includes the Storage Controller
eucalyptus-walrus - includes the Walrus storage system
eucalyptus-nc - includes the Node Controller that interacts with KVM through Libvirt to manage individual VMs
In a basic UEC setup, the system is composed of two machines (a front-end and a node). The front end runs both eucalyptus-cloud and eucalyptus-cc in this configuration. The node runs the node controller, eucalyptus-nc. It is possible to separate the cloud controller and cluster controller in a more complex multi-host setup. The following diagram depicts a simple setup:
UEC assumes that each node in the system belongs to a cluster and that each cluster belongs to a cloud. Each node runs the eucalyptus-nc service. Similarly, each cluster (again, there is only one cluster in this example) must run the eucalytpus-cc service. These components must be registered with each other before the system starts.