ZERMIA - A Fault Injector Framework for Testing Byzantine Fault Tolerant Protocols

Abstract

Byzantine fault tolerant (BFT) protocols are designed to increase system dependability and security. They guarantee liveness and correctness even in the presence of arbitrary faults. However, testing and validating BFT systems is not an easy task. As is the case for most concurrent and distributed applications, the correctness of these systems is not solely dependant on algorithm and protocol correctness. Ensuring the correct behaviour of BFT systems requires exhaustive testing under real-world scenarios. An approach is to use fault injection tools that deliberate introduce faults into a target system to observe its behaviour. However, existing tools tend to be designed for specific applications and systems, thus cannot be used generically.We argue that more advanced and powerful tools and frameworks are needed for testing the security and safety of distributed applications in general, and BFT systems in particular. Specifically, a fault injection framework that can be integrated into both client and server side applications, for testing them exhaustively.We present ZERMIA, a modular and extensible fault injection framework, designed for testing and validating concurrent and distributed applications. We validate ZERMIA’s principles by conduction a series of experiments on a distributed applications and a state of the art BFT library, to show the benefits of ZERMIA for testing and validating applications.