Sledge: a Serverless-first, Light-weight Wasm Runtime for the Edge
Sledge: a Serverless-first, Light-weight Wasm Runtime for the Edge
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DOI：
10.1145/3423211.3425680
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发表时间：
2020-12
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影响因子：
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通讯作者：
Phani Kishore Gadepalli;Sean P. McBride;Gregor Peach;L. Cherkasova;Gabriel Parmer
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作者：
Phani Kishore Gadepalli;Sean P. McBride;Gregor Peach;L. Cherkasova;Gabriel Parmer
具有实时延迟限制的新兴物联网应用需要在Edge上运行新的数据处理系统。无服务器计算提供了一种新的引人注目的范例，其中用户可以执行小型应用程序，而无需处理服务器配置和资源管理的操作问题。尽管有各种现有的商业和开源无服务器平台(利用虚拟机和容器)，但这些解决方案对于资源受限的Edge系统来说太重了(由于内存占用大和调用时间长)。此外，专注于每个客户端、短时间运行的计算的无服务器工作负载并不适合现有的通用计算系统。本文介绍了一种新颖高效的基于WebAssembly的无服务器Edge框架Sledge的设计与实现。Sledge针对支持无服务器工作负载的独特属性进行了优化：需要高密度多租户、低启动时间、突发性客户端请求率和短时间计算。Sledge针对这些限制而设计，提供(I)针对短期计算的优化调度策略和高效工作分配，以及(Ii)使用我们自己的基于WebAssembly的软件故障隔离基础设施实现的轻量级功能隔离模型。这些轻量级沙箱旨在支持高密度计算：具有快速启动和拆卸时间，以处理高客户端请求率。对具有不同工作负载和现实世界中的无服务器应用程序的Sledge进行的广泛评估证明了为Edge设计的无服务器优先运行时的有效性。与最快的开源无服务器框架之一Nuclio相比，Sledge支持高达4倍的吞吐量和4倍的延迟。
Emerging IoT applications with real-time latency constraints require new data processing systems operating at the Edge. Serverless computing offers a new compelling paradigm, where a user can execute a small application without handling the operational issues of server provisioning and resource management. Despite a variety of existing commercial and open source serverless platforms (utilizing VMs and containers), these solutions are too heavy-weight for a resource-constrained Edge systems (due to large memory footprint and high invocation time). Moreover, serverless workloads that focus on per-client, short-running computations are not an ideal fit for existing general purpose computing systems. In this paper, we present the design and implementation of Sledge -- a novel and efficient WebAssembly-based serverless framework for the Edge. Sledge is optimized for supporting unique properties of serverless workloads: the need for high density multi-tenancy, low startup time, bursty client request rates, and short-lived computations. Sledge is designed for these constraints by offering (i) optimized scheduling policies and efficient work-distribution for short-lived computations, and (ii) a light-weight function isolation model implemented using our own WebAssembly-based software fault isolation infrastructure. These lightweight sandboxes are designed to support high-density computation: with fast startup and teardown times to handle high client request rates. An extensive evaluation of Sledge with varying workloads and real-world serverless applications demonstrates the effectiveness of the designed serverless-first runtime for the Edge. Sledge supports up to 4 times higher throughput and 4 times lower latencies compared to Nuclio, one of the fastest open-source serverless frameworks.