The Unobservability Problem in Clouds
The Unobservability Problem in Clouds
复制标题
云中的不可观测性问题
DOI：
10.1109/iccac.2015.11
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
Harsha Ellanti
中科院分区：
文献类型：
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作者：
Anshul Gandhi;Parijat Dube;A. Karve;Andrzej Kochut;Harsha Ellanti
云是不透明的。云计算用户无法控制或监控有关其VM或服务的重要信息，如放置、真实资源分配、虚拟化开销等。同样，云提供商无法获得有关其用户部署的重要信息，如应用程序模型、每个VM的角色等。虽然这些信息不需要透露，但我们认为，这种信息的缺乏阻碍了用户充分了解其资源可用性，并限制了各种性能管理解决方案的可行性。我们将这种缺乏信息的现象称为“不可服务性”问题。在本文中，我们描述了不可观测性问题，并提供了各种使用案例，这些案例来自我们管理具有数百个虚拟机的中型云部署的经验，以及在EC2上的实验，这些实验突出了不可观测性对性能的严重影响，以及它对用户和云提供商施加的限制。我们发现，有趣的是，不可观测性往往会削弱云计算的潜在好处。为了解决不可观测性问题，我们提出并评估了一种实用的不可观测性问题解决方案，该解决方案无需对云进行任何检测或更改即可显示重要的不可观测信息。
The cloud is not transparent. Users of cloud computing cannot control or monitor important information about their VMs or services, such as placement, true resource allocation, virtualization overhead, etc. Likewise, cloud providers cannot obtain important information about their users' deployment such as the application model, the role of each VM, etc. While such information is not required to be revealed, we claim that this lack of information prevents users from fully understanding their resource availability, and limits the feasibility of various performance management solutions. We refer to this lack of information as the "Unobservability" problem. In this paper, we describe the unobservability problem and present various use cases from our experience managing a medium-scale cloud deployment with several hundred VMs and experiments on EC2 that highlight the severe impact of unobservability on performance, and the limitations it imposes on users and cloud providers. We show that, interestingly, unobservability often diminishes the potential benefits of cloud computing. To address unobservability, we present and evaluate a practical solution to the unobservability problem that reveals important unobservable information without requiring any instrumentation or changes to the cloud.