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Demand of using Docker is emerging not only in a single host, but also in large slaces such as disaster recovery across multiple DCs and user affinity across multiple continents. However in a large scale setting, deploying a Docker app is not straight forward due to the L3 network boundaries between DCs, and simple L2 overlays do not work as BUM packets are sent to every single DCs. We give a fully open and flexible solution by leveraging EVPN (L2 VPN over L3 network), Open vSwitch, and our yet another BGP daemon, GoBGP.
Live migration mechanism and its use to acheive greener data centers are both actively researched. However, live migration itself has non-negligible energy overhead and it is not properly evaluated in a combination with actual data center operation algorithms. We conducted a large scale simulation to evaluate migration energy overhead with real DC parameters.
Transferring large amount of VM memory is the biggest challenge of live migration. We found a large portion of VM memory contains page cache (a.k.a. file cache) in common cloud workloads (e.g. web server, database). Page cache teleportation leverages storage area network of the data center to transfer page cache and the other normal data in parallel, to efficiently migrate VMs with large page cache.
Writing high-performance distributed programs become more and more difficult as the number of underlying servers scale. Orleans, a distributed programming framework, frees application programmers from always thinking about complex locking and timing issues by leveragin an actor-based programming model. My internship in Mircrosoft Research was for bottleneck analysis and performance improvement of Orleans, which was further expanded by a latter intern and published in EuroSys 2016.
Live migration is a key technology to dynamically relocate VMs among physhyical hosts to achieve better energy efficiency, memory usage, and load balancing in DCs. We proposed and implemented "memory reusing" technique that transfers only the updated memory pages when a VM migrates back to a host on which the VM has been executed before. The technique significantly acceralates live migration and helps dynamic VM relocation.