We present a cloud resource procurement approach which not only
automates the selection of an appropriate cloud vendor but also
implements dynamic pricing. Three possible mechanisms are suggested
for cloud resource procurement: C-DSIC, C-BIC and C-OPT. C-DSIC is
dominant strategy incentive compatible, based on the VCG mechanism,
and is a low-bid Vickrey auction. C-BIC is Bayesian incentive
compatible, which achieves budget balance. C-BIC does not satisfy
individual rationality. In C-DSIC and C-BIC, the cloud vendor who
charges the lowest cost per unit QoS is declared the winner. In
C-OPT, the cloud vendor with the least virtual cost is declared the
winner. C-OPT overcomes the limitations of both C-DSIC and C-BIC.
C-OPT is not only Bayesian incentive compatible, but also individually
rational. Our experiments indicate that the resource procurement cost
decreases with increase in number of cloud vendors irrespective of the
mechanisms. We also propose a procurement module for a cloud broker
which can implement C-DSIC, C-BIC or C-OPT to perform resource
procurement in a cloud computing context. A cloud broker with such a
procurement module enables users to automate the choice of a cloud
vendor among many with diverse offerings, and is also an essential
first step towards implementing dynamic pricing in the cloud.