Yunfa Li

A Survey of Virtual Machine System: Current Technology and Future Trends

With the development of the computer technology, the virtual machine has been become the main research topic. Understanding of the current technology and future trends of virtual machine system greatly help to improve the service performance of system. Therefore, we describe the current technology and present the future trends of virtual machine system in the paper. In the current technology of virtual machine system, we mainly describe the virtualization technology, the resource scheduling technology, the migration technology, the security technology and the performance evaluation technology. In the future trends of virtual machine system, we mainly present an overview of the future CPU architecture, the management mode of future memory and resource, the future maintaining method of system security and the performance evaluation method of future multiple virtual machine system.

An Authenticated Encryption Mechanism for Secure Group Communication in Grid

In grid computing, group communication is an important strategy to realize large-scale information resource sharing. However, it is very difficult to ensure the security of group communication in large-scale grid environment. In this paper, based on the basic theories of threshold signature and the basic characteristics of group communication in grid, we present four algorithms, including keys generating, individual signature generating and verifying, group signature generating and encrypting, decrypting and group signature verifying, which constitute the authenticated encryption mechanism for group communication in grid. Finally, we validate the correctness of the authenticated encryption mechanism proposed in this paper and analyze its security. In addition, the validity of this mechanism is verified by the experiments. The results show that it is efficient to ensure the security of group communication in grid.

A Scalable Service Scheme for Secure Group Communication in Grid

In this paper, we propose a scalable service scheme for secure group communication in grid. In the service scheme, a series of methods and strategies are presented, such as the initialization methods for group member, administrative domain and virtual organization, the key distribution strategy and the rekeying strategy. In order to improve the scalability of this service scheme, the services for a group are logically divided into two hierarchical levels, which is in accordance with the characteristics of group communication in grid. In addition, in order to show the efficiency and the scalability of the service scheme, simulation experiments are done. The results show that the service scheme is efficient and scalable. Thus, the service scheme can satisfy the requirement of people in large-scale, dynamic grid environment.

Resource Allocation in Contending Virtualized Environments through VM Performance Modeling and Feedback

With active deployment of virtualization in large scale data centers and cloud computing environments, allocation and scheduling of virtual and physical resources raise more challenges and may have negative impacts on system performance due to: (1) the isolation between the guest Virtual Machines (VMs) and the Virtual Machines Monitor (VMM), and (2) the independent and even conflicting operations between multiple VMs. In this paper a stochastic model of resources in virtualized environments is proposed and resource allocation and scheduling algorithm are proposed to provide performance guarantees and service differentiation in contending conditions. In the proposed algorithm user behavior and workloads are characterized through the historical and real time performance profiling and estimation from hosted agents within individual VMs. The resources are allocated according to the demand as well as the performance of the targeted VMs based on the Suffer age aggregation and performance feedback. Experiments on a real Xen based virtualization environment with 3 VMs are conducted and evaluated for accuracy, efficiency, sensitivity, and overhead. The results show that the performance feedback based allocation can achieve a higher SLA satisfaction rate as 97.5%, a lower load imbalance index as 17.6%. The results also show that this algorithm is valid, effective and scalable for implementation in real virtualized environments.

Dynamic voltage/frequency scaling for power reduction in data centers: Enough or not?

Power consumption is becoming a critical and annoying problem to Data Centers (DCs). Higher power consumption results in more heat dissipation, cooling costs and makes servers more prone to failures. Various excellent workload and application-specific dynamic voltage/frequency scaling (DVS/DFS) algorithms have been proposed and deployed in many computing systems for power reduction and system reliabilities. However, there also exist some disadvantages associated with individual DVS/DFS algorithms when they are ported to DCs, where virtualization technologies and emerging multi-core processors are widely deployed. In this paper, we discuss several aspects and characteristics of DVS/DFS algorithms, e.g. performance, overheads, feasibility and usability in Data Centers. This paper also presents a discussion on the challenges of power reduction in large Data Centers.

A secure mechanism of group communication for pervasive grid

Cooperative processing is a representative application in pervasive grid and group communication is the key technique in this application. It is a great challenge to ensure the security of group communication in pervasive grid. In this paper, we first describe the service infrastructure of middleware for pervasive grid. Then, we present a secure mechanism of group communication and analyse the correctness and the security of the mechanism. Finally, we verify the validity of this mechanism by experiments. Results show that our proposed mechanism is efficient to ensure the security of group communication in pervasive grid.

An approach for service discovery based on semantic peer-to-peer

Service discovery is a key step during Peer-to-Peer (P2P) converging with Web Service. In this paper, a semantic-P2P based approach is presented for web service discovery. To enable the semantic web service, service profile is used to describe web service and as the service data source. The serviceexpertise based model is proposed for service node selection.

An adaptive management mechanism for resource scheduling in multiple virtual machine system

With the growth of hardware and software resources, the management of resource scheduling is becoming more and more difficult in multiple virtual machine system. It has become a very difficult problem that how to schedule the system resource and improve the service performance of resource. In order to solve this problem, we propose an adaptive management mechanism for resource scheduling. In the management mechanism, we first propose an adaptive management model for resource scheduling. Then, we present a genetic simulated annealing to resolve the management model. On the basis of the model and the algorithm, we design a management module. All these constitute an adaptive management mechanism for resource scheduling in multiple virtual machine system. In order to justify the feasibility and availability of the adaptive management mechanism for resource scheduling, a series of experiments have been done. The results show that it is feasible to adaptively manage and schedule the system resources and ensure the quality of service of resources in multiple virtual machine system.

A Real-Time Scheduling Mechanism of Resource for Multiple Virtual Machine System

With the growth of hardware and software resources, the management of virtual machine system is becoming more and more difficult. It has become a very difficult problem that how to schedule the system resource in real time and improve the service performance of resource in a multiple virtual machine system. In order to solve this problem, the authors propose a real-time scheduling mechanism of resource for multiple virtual machine system. In the real-time scheduling mechanism of resource, the authors first describe the architecture of multiple virtual machine system. Then, the authors present a real-time scheduling strategy of resource. In order to justify the feasibility and the availability of this resource scheduling mechanism, a series of experiments have been done. The results show that it is feasible to schedule the system resources for tasks in multiple virtual machine system.

Power Management Challenges in Virtualization Environments

Power is becoming a critical resource to large scale server systems and data centers. With active deployment of virtualization technology, power management raise more challenges and have negative impact on system performance due to : (1) the isolation between the guest Virtual Machines (VMs) and the Virtual Machines Manager (VMM), and (2)the independent operation between multiple VMs. In order to improve the conventional per-Operating System power management techniques and make it possible to control and globally coordinate the power management policies for virtualized resources among all VMs and the VMM, new features and sophisticated designs must be integrated into the VMM or Hypervisor. In this paper a review is presented on the power management challenges in virtualization environments and some proposed solutions are compared. This paper also presents some discussions on the research topics on power management in virtualization environments.