A Multi-Site Virtual Cluster System for Wide Area Networks

A virtual cluster is a promising technology for reducing management costs and improving capacity utilization in datacenters and computer centers. However, recent cluster virtualization systems do not have the maximum scalability and flexibility required, due to limited hardware resources at one site. Therefore, we are now developing an advanced cluster management system for multi-site virtual clusters; which provides a virtual cluster composed of distributed computer resources over wide area networks. This system has great advantages over other cluster management systems designed only for single-site resources; users can create a cluster of virtual machines from local and remote physical clusters in a scalable manner, and dynamically change the number of cluster nodes on demand, seamlessly. In our system, a multi-site cluster achieves a monolithic system view of cluster nodes to enable existing applications to be deployed quickly and managed flexibly, just as in physical clusters. In this paper, we propose an advanced cluster virtualization mechanism composed of two key techniques. An L2 network extension of virtual machine networks allows transparent deployment over networks for distributed virtual cluster nodes, and a transparent package caching mechanism greatly optimizes data transfers in virtual cluster deployment over network latencies. Experimental results show multi-site virtual clusters have sufficient feasibility in WAN environments and promise great scalability for a large-scale number of virtual nodes.