VirtualWires for Live Migrating Virtual Networks across Clouds

Despite significant advances in enabling live virtual machine (VM) migration within a virtualized—cloud— infrastructure, cross-cloud live migration remains an ad hoc, complex process. To create a network environment in which live migration can occur, clouds are beginning to expose virtual networks as a service. Connecting, managing and maintaining membership and routing information for—possibly incompatible—virtual networks as VMs migrate between clouds is non-trivial for both cloud providers and cloud users. In this paper, we present VirtualWire, a system in which cloud providers offer—instead of a virtual network abstraction—a connect/disconnect primitive that is much easier to manage. VirtualWire offers cloud users a consistent method to create complex logical network topologies in which the virtual network fabric itself is able to be elastically stretched or live migrated within or between clouds. Leveraging nested virtualization, we have implemented and evaluated VirtualWire across third-party clouds, including Amazon EC2, achieving cross-cloud live migration of VMs and network components with as low as 1.4 s of downtime.