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Recent exploration into the <i>unique</i> security challenges of cloud computing have shown that when virtual machines belonging to different customers share the same physical machine, new forms of cross-VM covert channel communication arise. In this paper, we explore one of these threats, L2 cache covert channels, and demonstrate the limits of these this(More)
Creating good adaptation policies is critical to building complex autonomic systems since it is such policies that define the system configuration used in any given situation. While online approaches based on control theory and rule-based expert systems are possible solutions, each has its disadvantages. Here, a hybrid approach is described that uses(More)
Virtualization-based server consolidation is an important technique for cost and energy reductions in data center environments and a key enabler of cloud computing. However, to ensure adequate application isolation and performance, consolidation demands runtime resource re-configuration, especially of multi-tier services that have dynamic, rapidly changing(More)
Idle desktop systems are frequently left powered, often because of applications that maintain network presence or to enable potential remote access. Unfortunately, an idle PC consumes up to 60% of its peak power. Solutions have been proposed that perform consolidation of idle desktop virtual machines. However, desktop VMs are often large requiring gigabytes(More)
Communication-oriented abstractions such as atomic multicast, group RPC, and protocols for location-independent mobile computing can simplify the development of complex applications built on distributed systems. This article describes Coyote, a system that supports the construction of highly modular and configurable versions of such abstractions. Coyote(More)
—Server consolidation based on virtualization is a key ingredient for improving power efficiency and resource utilization in cloud computing infrastructures. However, to provide satisfactory performance in such scenarios under changing application workloads, dynamic management of the consolidated resource pool is critical. Unfortunately, this type of(More)
Adaptive software that can react to changes in the execution environment or user requirements by switching algorithms at runtime is powerful yet difficult to implement, especially in distributed systems. This paper describes a software architecture for constructing such adaptive software and a graceful adaptation protocol that allows adaptations to be made(More)
Virtual machine technology enables agile system deployments in which software components can be cheaply moved, replicated, and allocated hardware resources in a controlled fashion. This paper examines how these facilities can be used to provide enhanced solutions to the classic problem of ensuring high availability while maintaining performance. By(More)
Automatic system monitoring and recovery has the potential to provide a low-cost solution for high availability. However, automating recovery is difficult in practice because of the challenge of accurate fault diagnosis in the presence of low coverage, poor localization ability , and false positives that are inherent in many widely used monitoring(More)