Boxer: FaaSt Ephemeral Elasticity for Off-the-Shelf Cloud Applications

TL;DR

Boxer enables off-the-shelf cloud applications to achieve rapid elasticity and cost savings by transparently integrating FaaS with traditional VM environments, without requiring application re-architecture.

Contribution

We introduce Boxer, a transparent interposition layer that emulates VM environments on FaaS platforms, allowing existing applications to benefit from ephemeral elasticity.

Findings

Recovery times over 5x faster than EC2 instances

Absorbs load spikes comparable to overprovisioned EC2 VMs

Significant performance and cost improvements

Abstract

Elasticity is a key property of cloud computing. However, elasticity is offered today at the granularity of virtual machines, which take tens of seconds to start. This is insufficient to react to load spikes and sudden failures in latency sensitive applications, leading users to resort to expensive overprovisioning. Function-as-a-Service (FaaS) provides significantly higher elasticity than VMs, but comes coupled with an event-triggered programming model and a constrained execution environment that makes them unsuitable for off-the-shelf applications. Previous work tries to overcome these obstacles but often requires re-architecting the applications. In this paper, we show how off-the-shelf applications can transparently benefit from ephemeral elasticity with FaaS. We built Boxer, an interposition layer spanning VMs and AWS Lambda, that intercepts application execution and emulates the network-of-hosts environment that applications expect when deployed in a conventional VM/container environment. The ephemeral elasticity of Boxer enables significant performance and cost savings for off-the-shelf applications with, e.g., recovery times over 5x faster than EC2 instances and absorbing load spikes comparable to overprovisioned EC2 VM instances.