Live Migration of an Entire Network (and its Hosts)
By decoupling applications from the underlying infrastructure, virtualization enables more flexible sharing of computing and network resources. Live virtual machine (VM) migration can move applications from one location to another without a disruption in service. However, applications often consist of multiple VMs and rely on the state of the underlying network for basic reachability, access control, and QoS functionality. Rather than migrating an individual VM, we show how to migrate an ensemble?the VMs, the network, and the management system?to a different physical infrastructure. Our LIME (LIve Migration of Ensembles) design leverages recent advances in Software Defined Networking (SDN) for a clear separation between the controller and the data-plane state in the switches. Transparent to the application running on the controller, LIME clones the data-plane state to a new set of switches. LIME then migrates the VMs, with both networks delivering traffic and maintaining synchronized state during the transition. Experiments with our prototype, built on the NOX OpenFlow controller, demonstrate the effectiveness of live migration of entire networks.