云計算中虛擬數據中心的服務質量的優化控制

林闖

摘 要：在云計算日趨流行的背景下，虛擬數據中心以其靈活、低成本、易部署等方面的優勢，成為云基礎設施的首選。服務調度和資源分配作為虛擬數據中心的核心問題，其性能和效率直接影響著上層云服務質量。而系統虛擬化特性和機制給服務調度和資源分配問題的研究帶來了新的挑戰。圍繞虛擬數據中心服務調度和資源分配問題，以理論模型、機制設計和特性分析為重點，開展深入研究。階段性成果包括以下內容：（1）對虛擬數據中心體系結構和系統虛擬化機制進行抽象，采用層次化的思想，利用隨機Petri網模型和組合模型相結合的方法，建立了虛擬數據中心的數學模型，對系統虛擬化引入的服務器整合和動態遷移等特性和機制進行描述和分析，并量化評價了虛擬數據中心的可信賴性。（2）提出了虛擬數據中心的服務調度框架，并建立了以優化可用性和響應時間為目標的虛擬數據中心服務調度的一般數學模型。首次引入一型和二型模糊邏輯系統解決虛擬化的動態特性和可用性需求的不確定性帶來的模糊性，在此基礎上提出了一種虛擬數據中心的服務調度算法。與傳統的調度算法相比，該算法能夠更好的保證可用性，同時實現了更好的響應時間性能。（3）著眼于數據中心的能耗和負載均衡，提出了虛擬數據中心資源分配問題的最優化數學模型。借助于經典的多維裝箱問題，并有效應對異構資源需求和能耗特性帶來的復雜性，設計了能耗優化的虛擬數據中心資源分配近似算法。實現了降低能耗，提高資源利用率，同時達到良好的負載均衡。（4）總結出了三種典型的虛擬數據中心管理系統結構。結合虛擬數據中心的特性和機制，對三種不同的虛擬數據中心管理系統的性能和可靠性進行了建模，并進行了量化分析比較。提出了為構建虛擬數據中心管理系統選擇適當結構的幾條基本原則，為虛擬數據中心工程實踐提供理論指導和參考。

關鍵詞：云計算 虛擬數據中心 服務調度 資源分配

Abstract：Focusing on the model， scheme design and performance analysis， this report carry on an intensive research on the service scheduling and resource provisioning of virtual data center. The work is summarized as follows：（1）Taking the hierarchy methodology， the model of virtual data center is built combining the stochastic petri nets and combinatorial model， based on the abstract of virtual data center structure and virtualization mechanisms. The characteristics and mechanisms of system virtualization are studied and analyzed， and the dependability of virtual data center is evaluated.（2）The framework model of service scheduling of virtual data center is proposed， and the optimization model is built with availability and responsiveness as the optimization objects. In order to overcome the scheduling difficulties caused by the uncertain workload of virtualized server nodes and the vagueness of availability， a graceful fuzzy prediction method based on the type-I and type-II fuzzy logic systems is first given. Then a novel dynamic scheduling algorithm named SALAF is designed. Experimental results show that the proposed algorithm SALAF can improve the total availability of the virtual data center while providing good responsiveness performance.（3）Aiming at the requirement of energy conservation and load balance， the optimization model of the resource provisioning is built. By defining the concept of energy marginal cost to relieve the complexity of heterogeneous resource demands and energy profits， an Energy-Efficient Dynamic Resource Provisioning （E2DRP） algorithm is proposed， by means of the multi-dimensional bin packing problem. The experimental results show that the proposed algorithms can improve energy efficiency， meanwhile achieve better server utilization and load-balance.（4）Three typical structures of the virtual data center management system （VDMS） are summarized， which are centralized， hierarchical and peer-to-peer structures. And the performance and reliability of the VDMS with the three typical structures is analyzed and evaluated. Some useful rules and conclusions are drawn and proved which are directive and with reference value for the construction of the virtual infrastructure management systems with higher performance， fault-tolerance and scalability.

Key Words：Cloud Computing；Virtual Data Center；Service Scheduling； Resource Provisioning

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