Elsevier Future Generation Computer Systems 2006 Seamless Live Migration of Virtual Machines over the MAN/WAN Franco Travostino, Paul Daspit, Leon Gommans, Chetan Jog, Cees de Laat, Joe Mambretti, Inder Monga,Bas van Oudenaarde, Satish Raghunath, Phil Wang Abstract The “VM Turntable” demonstrator at iGRID 2005 pioneered the integration of Virtual Machines (VMs) with deterministic “lightpath” network services across MAN/WAN. The results provide for a new stage of virtualization—one for which computation is no longer localized within a data center but rather can be migrated across geographical distances, with negligible downtime, transparently to running applications and external clients. A noteworthy data point indicates that a live VM was migrated between Amsterdam, NL and San Diego, USA with just 1 to 2 seconds of application downtime. When compared to intra-LAN local migrations, downtime is only about 5- 10 times greater despite 1,000 times higher round-trip-times. Keywords: Virtualization, Virtual Machine, lightpaths, control planes, optical networks. 1 Introduction Virtual Machines (VM) have long been a research topic in Computer Science because they hold a potential to accomplish tasks that are not dependent on particular hardware implementations or configurations. Recent advances [1] have shown that VM technology can support a fully featured operating system like Linux with a minimal runtime overhead when compared to native environments. However, to date VM instantiations still have to be localized at particular sites. A capability for migrating live VMs among multiple distributed sites provides a significant new benefit for VM-based environments. In previous publications, Pratt et al. introduce the notion of live migration, as approximating continuous operation of a set of processes even while they are being sent to another location. [2] This process occurs in lieu of performing a VM-wide suspend, copy, and resume. The live migration minimizes the downtime, i.e., the time when no CPU cycle is devoted to any of the VM-resident applications, neither at the source nor at the destination system. This paper describes the “VM Turntable” demonstrator, which shows that VMs can be migrated live, this time across geographical distances, transparently to applications and any external entity interacting with such applications. The demonstrator has been named “VM Turntable” to signify the recurring motion of VMs across sites. The migration process previously described [2] is shown to be ideally matched to the deterministic guarantees of the “lightpath” [3]—an end-to-end logical link in an optical physical network. This new approach contributes a Franco Travostino, Paul Daspit, Chetan Jog, Inder Monga and Phil Wang ({travos, pdaspit, cjog, imonga, pywang}@nortel.com) are with Nortel Labs. Satish Raghunath was with Nortel Labs, he is now with Juniper Networks (rsatish@yahoo.com). Joe Mambretti (j-mambretti@northwestern.edu) is with International Center for Advanced Internet Research (iCAIR) at Northwestern University. Leon Gommans and Cees de Laat ({lgommans,delaat}@science.uva.nl)) are with the Advanced Internet Research group of the Universiteit van Amsterdam. Bas van Oudernaarde was with the University of Amsterdam, he is now with Finalist IT Group (bas@finalist.com).