虚拟计算环境的重要目标之一,就是在动态、开放、多变的网络环境中对分布异构资源按需进行聚合,并提供有效的资源发布、发现、订阅等机制.通过服务来抽象和封装资源是资源虚拟化的主要手段之一,但现有面向服务的体系结构(service oriented architecture,简称SOA)所采用的“以服务提供商为中心”的服务组织模式容易导致用户发现和订阅服务的难度随着服务的增加而增加.提出一种用户驱动的服务聚合技术,即根据用户需求,将功能相似的服务聚合成服务池并封装为单一的虚拟服务,随后根据用户QoS需求进行自动协商,选出最佳服务或服务组合.该方法的特点在于将服务池作为用户发现和订阅的唯一实体,从用户角度将大量服务聚合成为相对稳定和统一的资源视图,屏蔽资源的复杂性、多样性和多变性,支持自动QoS协商,从而有效提高用户对服务资源的利用.
The Virtual Computing Environment (VCE) should "on demand" collect and aggregate distributed resources, and provide efficient publication, discovery and subscription mechanisms. Since resources are usually virtualized as services, the goals of the VCE largely rely on service oriented computing technologies. However, Service Oriented Architecture (SOA) organizes services in a "provider-centric" manner, which brings a critical problem: More services come to being, more complex and difficult the service discovery and subscription become. A "consumer-centric" approach is proposed to addressing this problem. First, function similar services according to consumer's functionality requirements are dynamically aggregated as a service pool. The pool will act as a virtual service so that consumers only discover and subscribe the service pool instead of a large number of candidate services. The qualities of the services in a service pool could form a spectrum of QoS so that consumer's quality requirements can be satisfied by automated QoS negotiation. Based on the service pool, the VCE could provide an "on demand of consumers" way for resource sharing.