Tracing Function Dependencies across Clouds

In this paper, we present Lowgo, a crosscloud tracing tool for capturing causal relationships in serverless applications. To do so, Lowgo records dependencies between functions, through cloud services, and across regions to facilitate debugging and reasoning about highly concurrent, multi-cloud applications. We empirically evaluate Lowgo using microbenchmarks and multi-function and multi-cloud applications. We find that Lowgo is able to capture causal dependencies with overhead that ranges from 2-12%, which is less than half that of the best-performing, cloud-specific approach.