Building an Elastic Cloud out of Small Datacenters

Cloud providers may operate large-scale data centers in a few locations. We argue that deploying many small-scale data centers at network edge can significantly improve user experience in terms of latency. Small-scale data centers, however, may not be able to provide elastic services. In this paper, we investigate distributed small-scale data centers with load reallocation where jobs that cannot be suitably processed locally will be reallocated to remote data centers. We formulate an optimization problem for load reallocation in distributed data centers, provide performance comparisons among different alternatives and offer insights on handling multiple job types. We develop online optimization algorithms that can be operated in a decentralized and measurement-based fashion to dynamically reallocate load in response to sudden load surges. The experimental results demonstrate that elasticity can be practically provided by small-scale data centers enhanced with effective load reallocation techniques.