Bandwidth Guarantee under Demand Uncertainty in Multi-tenant Clouds

The shared multi-tenant nature of cloud network infrastructures has caused poor application performance in the clouds due to unpredictable network performance. To provide bandwidth guarantee, several virtual network abstractions have been proposed which allow the tenants to specify and reserve virtual clusters with required network bandwidth between the VMs. However, all of these existing proposals require the tenants to deterministically characterize the exact bandwidth demands in the abstractions, which can be difficult and result in inefficient bandwidth reservation due to the demand uncertainty. In this paper, we propose a virtual cluster abstraction with stochastic bandwidth requirements between VMs, called Stochastic Virtual Cluster (SVC), which probabilistically models the bandwidth demand uncertainty. Based on SVC, we propose a network sharing framework and efficient VM allocation algorithms to ensure that the bandwidth demands of tenants on any link are satisfied with a high probability, while minimizing the bandwidth occupancy cost on links. Using simulations, we demonstrate the effectiveness of SVC for accommodating cloud application workloads with highly volatile bandwidth demands, in the way of achieving the trade-off between the job concurrency and average job running time.