Process-as-a-Service: Unifying Elastic and Stateful Clouds with Serverless Processes

Marcin Copik, Alexandru Calotoiu, Gyorgy Réthy, Roman Böhringer, Rodrigo Bruno, Torsten Hoefler

Abstract: Fine-grained serverless functions power many new applications that benefit from elastic scaling and pay-as-you-use billing model with minimal infrastructure management overhead. To achieve these properties, Function-as-a-Service (FaaS) platforms disaggregate compute and state and, consequently, introduce non-trivial costs due to the loss of data locality when accessing state, complex control plane interactions, and expensive inter-function communication. We revisit the foundations of FaaS and propose a new cloud abstraction, the cloud process, that retains all the benefits of FaaS while significantly reducing the overheads that result from disaggregation. We show how established operating system abstractions can be adapted to provide powerful granular computing on dynamically provisioned cloud resources while building our Process as a Service (PraaS) platform. PraaS improves current FaaS by offering data locality, fast invocations, and efficient communication. PraaS delivers remote invocations up to 17× faster and reduces communication overhead by up to 99%.