Limitless FaaS: Overcoming serverless functions execution time limits with invoke driven architecture and memory checkpoints

Abstract: Function-as-a-Service (FaaS) allows to directly submit function code to a cloud provider without the burden of managing infrastructure resources. Each cloud provider establishes execution time limits to their FaaS offerings, which impose the risk of spending computation time without achieving partial results. In this work, a framework that enables limitless execution time in FaaS, with little to no modifications to the user-provided function code, is presented. After a thorough literature and theoretical framework review, Apache OpenWhisk Actions and the DMCTP checkpoint-and-restore (CR) tool were selected. With these, dependent successive serverless same-function invocations that exploit the persistence of partial results were implemented. The solution was submitted to the FaaSDom benchmark and time metrics were collected. Additionally, the solution was characterized in terms of the Serverless Trilemma. The resultant system, even at this proof-of-concept state, offers a lot of value to companies that rely heavily on serverless architecture.