Capybara: an Edge-Friendly Distributed Object Store for Diverse Serverless Functions

Abstract

While originally designed for the cloud, the benefits of the serverless paradigm are also vital in Edge/Fog computing environments. This paper presents Capybara, a new scalable, programmable distributed object store for storing and sharing serverless function data objects (state) on edge infrastructures. The key innovations here are (1) achieving scalability and avoiding the significant DRAM cost of indexing metadata servers through a “game-theoretic” DHT-based P2P architecture; (2) providing edge users with a “programmable” handler abstraction to customize data management policies, such as different function image caching policies, warm container “keep-alive” durations, data access control methods, and data replication policies. We implement Capybara prototype on the Pastry DHT, deploy it on 150 Amazon EC2 nodes, and evaluate it by conducting real-world experiments, demonstrating its significant gains in data locality, application-specific customization, and scalability compared to the state-of-the-art.