Transparent migration of virtual infrastructures in large datacenters for Cloud computing

Cloud-enabled datacenters need advanced support for an integrated management of platform virtualization technologies. The networking infrastructure of large-scale datacenters is implemented according to redundant multi-tiered architectures whose layers operate at Layer 3 of the networking stack. Splitting the network infrastructure of a datacenter in a number of IP subnets, however, creates limits to the migration of Virtual Machines, reducing the possibility for administrators to efficiently balance the load and reduce the energy consumption of the whole infrastructure. In this paper we propose an innovative solution that allows transparent migration of Virtual Machines across the whole datacenter, based on the coordinated use of NAT rules that need to be consistently managed across the layers of the datacenter networking infrastructure. We describe in details how our approach can be easily implemented with current network devices without any modification to their hardware and present an experimental evaluation of an early prototype of our solution.