Enabling Work-Conserving Bandwidth Guarantees for Multi-tenant Datacenters with Network Support

Bandwidth guarantees and work conservation are the two most desirable properties for multi-tenant datacenters, which are the key to providing predictable performance for tenants' applications by giving lower bounds on bandwidth that each tenant can obtain, and to improving network utilization for datacenter providers by enabling the reuse of spare network bandwidth or unused bandwidth allocated to a tenant. Current approaches, however, cannot effectively achieve work-conserving bandwidth guarantees, as they either cannot provide accurate bandwidth guarantees or are not work-conserving. In this paper, we present FastLane, a host-based mechanism with network support that can effectively achieve bandwidth guarantees and work conservation simultaneously. Specifically, FastLane splits every flow between a pair of virtual machines into two subflows which are marked with red color and green color respectively. The subflow with red color is rate-limited at the rate of its corresponding guarantee to achieve bandwidth guarantees, while the one with green color is used to achieve work conservation. Moreover, FastLane leverages the weighted fair queueing which is widely available in commodity switches to slice network bandwidth for each kind of subflows. Experimental results show that our approach can achieve accurate bandwidth guarantees and effectively utilize the network.