Predictable Open Source FaaS Function Chains

Function as a Service (FaaS) provides a way to execute modular pieces of code in cloud environments. FaaS also supports the implementation of distributed cloud applications by deploying function chains.In this paper, we introduce a simulation framework for function chains using asynchronous invocations. By using our simulator the completion time distribution of the individual function invocations can be estimated as well as the completion time of the distribution of the whole function chain.We evaluate the results of our simulation framework by using compute-intensive, Python3 based function chains that implement image transforming operations. We also propose cost decreasing methods for function chains with asynchronous invocations.