Research On Virtual Community Cloud And The Policy Of Replica Allocation Of Cloud Service

In some scientific domains such as Bioinformatics, lots of virtual communitiesare formed based on internet technology in order to share their domain-specificresource such as data and software. Individuals or organizations engaged in specificdomains can apply for joining to the virtual community according to certain entryconditions. Therefore, members of a virtual community can access its resources whilesharing their own resources. In such a distributed and dynamic environment, it is agood choice to deliver resources to be shared using Web Services. So, these resourcesof the virtual community can be considered a Web Service Community.In traditional Virtual Community, some preponderant web services are invokedfrequently compared to others. Meanwhile, it is impossible for users to change thehosting environment of a third-party Web Service because of its autonomy. It seemsto be unavoidable that the hosting resource of some web services is overloaded, butthat of others may be relatively idle. This would lead to a very poor utilization of webservice hosting resources and largely affect the quality of service.Cloud computing is a model for enabling ubiquitous, convenient, on-demandnetwork access to a shared pool of configurable computing resources (e.g., networks,servers, storage, applications, and services) that can be rapidly provisioned andreleased with minimal management effort or service provider interaction. CommunityCloud consolidates a certain size of computing and storage resources into a resourcepool by the advantage of cloud computing model, which have extraordinarysuperiority for ensuring the reliance and scalability of web service by providingsharable and configurable resource pools. As the development of technologies aboutCloud Computing, it would be valuable to let community members get a chance ofenjoying flexible services that is usually provided by a cloudy environment, andremain their historic applications on the service community still available at the sametime.In fact, there have been many studies on community cloud. According to thedefinition by NIST, a community cloud is a cloud for a specific community ofconsumers from organizations. As far as a member of the associated community is concerned, a community cloud is indeed a private cloud for that particularcommunity.Virtual Community Cloud (VCC) falls into the category of Community Cloud,nevertheless, its infrastructure comes purely from the automatic web service hostingresources, which will be characteristic of distribution, dynamic and extended. Byutilizing the virtualization technology, VCC organizes the idle resource provided bygeographically-distributed community members into a virtual resource pool to beshared by its members, and it can ensure the resilience and scalability in practicalapplications.Quality of cloud service is a hot topic in the studying of cloud computing. VCCis made up of numbers of individuals or organizations distributed geographicallywhose spare resources are used to form a cloud environment. Community cloud takesthe executable container of a Web service as its basic resource unit. This thesisintroduces a hierarchical model of virtual community according to its features, andthen explores the approaches to the resource replica allocation and the construction ofexecutable container, which will be treated as a unit for resource delivery andscheduling. The analysis and simulation shows that the policy can improve the qualityof cloud services to a large extent.