  The serverless computing model has evolved as one of the key solutions in the
cloud for fast autoscaling and capacity planning. In edge computing
environments, however, the serverless model is challenged by the system
heterogeneity and performance variability. In this paper, we introduce
BenchFaaS, an open-source edge computing network testbed which automates the
deployment and benchmarking of serverless functions. Our edge computing network
considers a cluster of virtual machines and Raspberry Pis, and is designed to
benchmark serverless functions under different hardware and network conditions.
We measure and evaluate: (i) overhead incurred by testbed, (ii) performance of
compute intensive tasks, (iii) impact of application payload size, (iv)
scalability, and (v) performance of chained serverless functions. We share the
lessons learnt in engineering and implementing the testbed. We present the
measurement results and analyze the impact of networked infrastructure on
serverless performance. The measurements indicate that a properly dimensioned
edge computing network can effectively serve as a serverless infrastructure.
