This paper proposes a new cloud computing service model, Hardware as a Service (HaaS), that is based on the idea of implementing ``elastic data centers'' that provide a data center administrator with resources located at different data centers as demand requires. To demonstrate the feasibility of the proposed model, we have developed what we call an Inter-cloud Resource Integration System (Iris) by using nested virtualization and OpenFlow technologies. Iris dynamically configures and provides a virtual infrastructure over inter-cloud resources, on which an IaaS cloud can run. Using Iris, we have confirmed an IaaS cloud can seamlessly extend and manage resources over multiple data centers. The experimental results on an emulated inter-cloud environment show that the overheads of the HaaS layer are acceptable when the network latency is less than 10 msec. We believe these results provide new insight to help establish inter-cloud computing.
['Ryousei Takano', 'Atsuko Takefusa', 'Hidemoto Nakada', 'Seiya Yanagita', 'Tomohiro Kudoh']
Iris: An Inter-cloud Resource Integration System for Elastic Cloud Data Centers