FaasKeeper: a Blueprint for Serverless Services

Abstract

FaaS (Function-as-a-Service) brought a fundamental shift into cloud computing: (persistent) virtual machines have been replaced with dynamically allocated resources, trading locality and statefulness for a pay-as-you-go model more suitable for varying and infrequent workloads. However, adapting services to function within the serverless paradigm while still fulfilling requirements is challenging. In this work, we introduce a design blueprint for creating complex serverless services and contribute a set of requirements for efficient and scalable FaaS computing. To showcase our approach, we focus on ZooKeeper, a centralized coordination service that offers a safe and wait-free consensus mechanism but requires a persistent allocation of computing resources that does not offer the flexibility needed to handle variable workloads. We design FaaS-Keeper, the first coordination service built on serverless functions and cloud-native services. FaaSKeeper provides the same consistency guarantees and interface as ZooKeeper with a price model proportional to the activity in the system. In addition, we define synchronization primitives to extend the capabilities of scalable cloud storage services with consensus semantics needed for strong data consistency.

Streaming vs. Functions: A Cost Perspective on Cloud Event Processing

“…A key element to horizontal scalability is that function instances logically exist only for the duration of a single invocation and do not support any state beyond that execution [10]. To support stateful applications, functions usually leverage serverless, payper-request cloud datastores such as Google Cloud Firestore 7 or AWS DynamoDB 8 [25,26].…”

“…FaaS platforms, e.g., AWS Lambda 3 and Google Cloud Functions 4 , allow developers to deploy small, stateless functions on managed infrastructure that are billed per invocation and run duration. These functions can also be chained to build larger applications, e.g., through synchronous invocations or asynchronously by sharing state in a database [9,10]. The managed approach promises high elasticity and scalability for developers and allows cloud service providers to allocate their infrastructure more efficiently [11,12].…”