Friday: Global Comprehension for Distributed Replay

Debugging and profiling large-scale distributed applications is a daunting task. We present Friday, a system for debugging distributed applications that combines deterministic replay of components with the power of symbolic, low-level debugging and a simple language for expressing higher-level distributed conditions and actions. Friday allows the programmer to understand the collective state and dynamics of a distributed collection of coordinated application components. To evaluate Friday, we consider several distributed problems, including routing consistency in overlay networks, and temporal state abnormalities caused by route flaps. We show via micro-benchmarks and larger-scale application measurement that Friday can be used interactively to debug large distributed applications under replay on common hardware.