[论文解读] Kubernetes as an Availability Manager for Microservice Applications

Leila Abdollahi Vayghan, Mohamed Aymen Saied+2 more|arXiv (Cornell University)|Jan 15, 2019

Software System Performance and Reliability参考文献 12被引用 33

一句话总结

本文评估 Kubernetes 如何为微服务应用管理可用性，探索公共/私有云架构、Kubernetes 自愈（healing）与冗余，并与可用性管理框架（AMF）进行比较。

ABSTRACT

The move towards the microservice based architecture is well underway. In this architectural style, small and loosely coupled modules are developed, deployed, and scaled independently to compose cloud-native applications. However, for carrier-grade service providers to migrate to the microservices architectural style, availability remains a concern. Kubernetes is an open source platform that defines a set of building blocks which collectively provide mechanisms for deploying, maintaining, scaling, and healing containerized microservices. Thus, Kubernetes hides the complexity of microservice orchestration while managing their availability. In a preliminary work we evaluated Kubernetes, using its default configuration, from the availability perspective in a private cloud settings. In this paper, we investigate more architectures and conduct more experiments to evaluate the availability that Kubernetes delivers for its managed microservices. We present different architectures for public and private clouds. We evaluate the availability achievable through the healing capability of Kubernetes. We investigate the impact of adding redundancy on the availability of microservice based applications. We conduct experiments under the default configuration of Kubernetes as well as under its most responsive one. We also perform a comparative evaluation with the Availability Management Framework (AMF), which is a proven solution as a middleware service for managing high-availability. The results of our investigations show that in certain cases, the service outage for applications managed with Kubernetes is significantly high.

研究动机与目标

• 在运营商级环境中推动向微服务迁移，同时确保可用性。
• 评估 Kubernetes 在私有云和公有云架构中的默认配置与优化配置的可用性。
• 评估在微服务应用的可用性方面添加冗余的影响。
• 将基于 Kubernetes 的可用性管理与可用性管理框架（AMF）进行比较。
• 分析 Kubernetes 自愈的有效性影响服务连续性的场景。

提出的方法

• 提出在公共云和私有云中部署微服务以研究可用性的架构。
• 将 Kubernetes 自愈机制作为维持服务可用性的手段进行考察。
• 在 Kubernetes 默认配置及其最具响应性的配置下进行实验。
• 与可用性管理框架（AMF）作为高可用性中间件解决方案进行比较评估。
• 分析冗余对微服务部署可用性的影响。

实验结果

研究问题

• RQ1 Kubernetes 自愈在不同云架构中对托管微服务的可用性有何影响？
• RQ2 应用冗余对基于微服务的应用的可用性有何影响？
• RQ3 Kubernetes 与 AMF 在为微服务提供高可用性方面有何差异？
• RQ4 在公有云和私有云部署中，启用 Kubernetes 的可用性有何不同？
• RQ5 默认配置与最具响应性的 Kubernetes 配置对停机行为有何影响？

主要发现

• 在某些情况下，Kubernetes 管理的应用程序的服务中断可能相当高。
• Kubernetes 自愈能力有助于可用性，具体效果取决于配置。
• 冗余可以改变可用性结果，在某些情景下可观察到改进。
• Kubernetes 的可用性性能与 AMF 不同，表明 Kubernetes 原生管理与基于中间件的方法之间存在权衡。
• 公有云与私有云架构在 Kubernetes 管理下显示出不同的可用性特征。