The Ifs and Buts of Less is More: A Serverless Computing Reality Check

Abstract

Serverless computing defines a pay-as-you-go cloud execution model, where the unit of computation is a function that a cloud provider executes and auto-scales on behalf of a cloud consumer. Serverless suggests not (or less) caring about servers but focusing (more) on business logic expressed in functions. Server’less’ may be ‘more’ when getting developer expectations and platform propositions right and when engineering solutions that take specific behavior and constraints of (current) Function-as-a-Service platforms into account. To this end, in this invited paper, we present a summary of findings and lessons learned from a series of research experiments conducted over the past two years. We argue that careful attention must be placed on the promises associated with the serverless model, provide a reality-check for five common assumptions, and suggest ways to mitigate unwanted effects. Our findings focus on application workload distribution and computational processing complexity, the specific auto-scaling mechanisms in place, the behavior and strategies implemented with operational tasks, the constraints and limitations existing when composing functions, and the costs of executing functions.