关键词: 虚拟化；Web服务；动态负载均衡；自动化控制；集群；任务调度

Abstract:

In order to improve the scalability and automation of web cluster servers, we study many cluster systems from the aspects of virtualization and load balancing, propose a load information collection algorithm based on the Xen server virtualization platform, design and implement a modeling system called XCluster which can automatically control the cluster scale according to the load status. A monitoring service in the new model collects and quantifies the loads of the hosts and active nodes in real time. VM controllers will be notified to deploy more VMs from an optimumload host when lightload nodes are in short supply; however, when there are too many lightload nodes, a number of VMs will be shutdown to release more hardware resources. Theoretical analysis and experimental results show that the XCluster can make full use of the unique capabilities of the virtualization platform which can manage all backend nodes in an economical way. By scheduling VMs, the clusters can avoid resource waste, yet maintaining the applications quality of service within an acceptable size.

Key words: virtualization;web server;dynamic loadbalancing;automation control;cluster;task scheduling