  Cloud service brokerage is an emerging technology that attempts to simplify
the consumption and operation of hybrid clouds. Today's cloud brokers attempt
to insulate consumers from the vagaries of multiple clouds. To achieve the
insulation, the modern cloud broker needs to disguise itself as the
end-provider to consumers by creating and operating a virtual data center
construct that we call a meta-cloud, which is assembled on top of a set of
participating supplier clouds. It is crucial for such a cloud broker to be
considered a trusted partner both by cloud consumers and by the underpinning
cloud suppliers. A fundamental tenet of brokerage trust is vendor neutrality.
On the one hand, cloud consumers will be comfortable if a cloud broker
guarantees that they will not be led through a preferred path. And on the other
hand, cloud suppliers would be more interested in partnering with a cloud
broker who promises a fair apportioning of client provisioning requests.
Because consumer and supplier trust on a meta-cloud broker stems from the
assumption of being agnostic to supplier clouds, there is a need for a test
strategy that verifies the fairness of cloud brokerage. In this paper, we
propose a calculus of fairness that defines the rules to determine the
operational behavior of a cloud broker. The calculus uses temporal logic to
model the fact that fairness is a trait that has to be ascertained over time;
it is not a characteristic that can be judged at a per-request fulfillment
level. Using our temporal calculus of fairness as the basis, we propose an
algorithm to determine the fairness of a broker probabilistically, based on its
observed request apportioning policies. Our model for the fairness of cloud
broker behavior also factors in inter-provider variables such as cost
divergence and capacity variance.

Distributed, Parallel, and Cluster Computing