In this paper we present UDON, a novel Utility Driven Overlay Network framework for routing service requests in highly dynamic large scale shared infrastructures. UDON combines an application provided utility function to express the services’s QoS in a compact way, with an epidemic protocol to disseminate this information in a scalable and robust way. Experimental analysis with a simulation model suggests that the proposed overlay allocates requests to service instances that match their QoS requirements with a high probability and low overhead, adapting well to a wide variety of conditions.