LIBRA: An Economical Hybrid Approach for Cloud Applications with Strict SLAs
LIBRA: An Economical Hybrid Approach for Cloud Applications with Strict SLAs
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DOI：
10.1109/ic2e52221.2021.00028
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发表时间：
2021-04
期刊：
影响因子：
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通讯作者：
A. Raza;Zongshun Zhang;Nabeel Akhtar;Vatche Isahagian;I. Matta
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作者：
A. Raza;Zongshun Zhang;Nabeel Akhtar;Vatche Isahagian;I. Matta
功能即服务（FaaS）最近出现，与云结构即服务（IaaS）相比，它可以降低运行云应用程序的部署成本。FaaS遵循无服务器的“按需付费”计算模型;它的每单位执行时间成本较高，但通常应用程序功能的配置时间较短（启动延迟）。IaaS需要配置虚拟机，而虚拟机通常会遭受更长的冷启动延迟，从而导致更高的排队延迟和更高的请求丢弃率。我们提出了LIBRA，这是一种平衡（混合）方法，它利用基于VM的资源和无服务器资源来有效地管理应用程序的云资源。LIBRA密切监控应用程序需求，并提供适当的VM和无服务器资源，以最大限度地降低运行成本并满足服务级别协议。与最先进的技术不同，LIBRA不仅隐藏了VM冷启动延迟，从而通过利用无服务器减少了响应时间，而且还将低速率突发部分的需求引导到无服务器，这样比启动新VM的成本更低。我们在模拟环境中以及AWS商业云上评估了LIBRA的真实的跟踪。我们的研究结果表明，LIBRA优于其他资源配置政策，包括最近的混合方法- LIBRA实现了85%以上的SLA违规减少和高达53%的成本节约。
Function-as-a-Service (FaaS) has recently emerged to reduce the deployment cost of running cloud applications compared to Infrastructure-as-a-Service (IaaS). FaaS follows a serverless “pay-as-you-go” computing model; it comes at a higher cost per unit of execution time but typically application functions experience lower provisioning time (startup delay). IaaS requires the provisioning of Virtual Machines, which typically suffer from longer cold-start delays that cause higher queuing delays and higher request drop rates. We present LIBRA, a balanced (hybrid) approach that leverages both VM-based and serverless resources to efficiently manage cloud resources for the applications. LIBRA closely monitors the application demand and provisions appropriate VM and serverless resources such that the running cost is minimized and Service-Level Agreements are met. Unlike state of the art, LIBRA not only hides VM cold-start delays, and hence reduces response time, by leveraging serverless, but also directs a low-rate bursty portion of the demand to serverless where it would be less costly than spinning up new VMs. We evaluate LIBRA on real traces in a simulated environment as well as on the AWS commercial cloud. Our results show that LIBRA outperforms other resource-provisioning policies, including a recent hybrid approach - LIBRA achieves more than 85% reduction in SLA violations and up to 53% cost savings.