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作者: 杜才华
答辩日期: 2008-06-07
授予单位: 中国科学院软件研究所
授予地点: 软件研究所
学位: 博士
关键词: Web应用服务器 ; 集群 ; 负载平衡 ; 动态扩展
其他题名: OnceCluster:A Design and Implementation of an Extensible Cluster Framework for WEB Application Server
摘要: 随着Internet的迅速发展,大型的企业信息化系统以及以B2C和C2C等模式为代表的电子商务领域的应用逐渐成为当今软件技术的主流趋势和竞争焦点。在该领域,作为信息系统基础平台的应用服务器面临极大的负载压力,通过应用服务器集群系统来扩展平台的计算能力是目前业界重要的研究课题。 然而,目前广泛适用的应用服务器集群系统尚存在一些不足,一方面,集群架构缺乏静态可扩展性。用户无法根据当前的网络状态和软硬件环境,灵活的配置集群系统所需的底层通讯框架以及负载平衡算法。另一方面,集群系统缺乏动态可扩展性。目前的集群框架无法根据当前负载的大小动态地伸缩规模,在高负载时无法提供足够的计算能力,而在负载低时,会产生空闲节点造成资源浪费。 针对集群系统的动态扩展需求,本文提出了一种易扩展的集群框架:OnceCluster,并针对该框架的设计以及实现过程当中遇到的相关技术问题展开研究和讨论。 首先,本文对当今主流的J2EE应用服务器集群的现状进行了分析,总结几种主要集群架构的特点,并在此基础上提出了一种易扩展的集群架构:OnceCluster。该架构研究主要包括三部分:高效易扩展的负载平衡器,易扩展的集群基础设施,以及集群成员动态扩展机制。 其次,本文分别针对OnceCluster的三个主要组成部分的设计与实现进行阐述。在负载平衡器部分,本文研究了负载平衡器的实现方式和负载平衡算法的设计,分析了影响负载平衡器性能的关键问题,并在此基础之上设计并实现了灵活易插拔的负载平衡器框架,该框架利用XML结构化对象模型和Java虚拟机的运行时动态绑定机制,实现了一个基于的IoC的对象生成机制,并基于该机制实现了组通讯管理模块,负载平衡算法模块和线程池模块。在集群基础设施部分,本文研究了集群系统和应用服务器之间交互关系,集群信息状态同步和失效恢复机制,并设计与实现了一种可灵活替换的集群基础设施通讯框架。在集群成员动态扩展机制部分,本文通过研究了一种分布式的集群成员管理机制,及时侦测集群成员的存活信息及负载状态,自动的启动或关闭集群成员,对集群规模进行动态地伸缩。 论文的研究成果已经应用于中国科学院软件研究所自主研发的基于J2EE规范的应用服务器OnceAS当中,目前,OnceAS已成功用于电子政务,电子商务和ERP系统等领域。
英文摘要: With the rapid development of Internet, Enterprise Information Systems as well as Economic Systems that based on B2B or C2C model gradually become the mainstream of today's software technology trends and competitive focus. The Application Server that runs as basic platform for these systems is facing tremendous load pressure. Using cluster to expand system’s compute capacity is an important research topic. At present, however, widely applicable application server cluster system has a number of shortcomings. First, the cluster’s static framework is lack of scalability. User can’t config the underlying communication mechanism as well as load balancing algorithm flexibly based on the difference in network state and software or hardware environment. Secondly, Cluster can’t dynamically expand itself. Cluster framework can’t adjust its size according to the amount of load that it received. If there are a lot of idle nodes running, is bound to bring greater waste of resources. This paper proposes an extensible cluster framework:OnceCluster, and gives detailed explanation and design issues as well as technical problems encountered. Firstly, this paper made a detailed analysis of today’s mainstream J2EE application server clusters, and the similarities and differences in the ways merits. Based on this, we propose a framework:OnceCluster, for easy expansion of the cluster. The framework comprises three main parts: an efficient extensible load balancer, an expansible cluster infrastructure, as well as a dynamic node management mechanism. Secondly, we describe the various components of this frame work in detail. In the part of Load Balancer, we study the pattern to imply load balancer, the way to achieve efficient load balancer algorithms, and the key issues that may have serious impact on load balancer. After that we proposed a load balancer framework that can be flexibly extended. This framework uses XML Object Model and Java virtual machine runtime dynamic binding mechanism to construct a target based on the IoC formation mechanism. Load Balancer group communications management module, load balancing algorithm module and thread pool module use this mechanism to be loaded by load balancer. In the part of cluster infrastructure, we studied the interaction between cluster framework and web application server, the mechanism to achieve status synchronization and recovery from failure. In the part of node expansion mechanism, the paper proposed a distributed cluster node management mechanism which timely detects cluster information, as well as the load status of each server. It will start up or shut down cluster members automatically according the overall status of the cluster. The research results have been applied to J2EE application server OnceAS developed by Institute of Software, Chinese Academy of Sciences. At present, OnceAS has been used successfully in e-government, e-commerce and ERP systems, and other fields.
语种: 中文
内容类型: 学位论文
Appears in Collections:软件工程技术研究开发中心 _学位论文

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Recommended Citation:
杜才华. OnceCluster:一种易扩展WEB应用服务器集群框架的设计与实现[D]. 软件研究所. 中国科学院软件研究所. 2008-06-07.
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