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arXiv · 2109.11987

Formal Verification of a Distributed Dynamic Reconfiguration Protocol

William Schultz·Ian Dardik·Stavros Tripakis
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Abstract

We present a formal, machine checked TLA+ safety proof of MongoRaftReconfig, a distributed dynamic reconfiguration protocol. MongoRaftReconfig was designed for and implemented in MongoDB, a distributed database whose replication protocol is derived from the Raft consensus algorithm. We present an inductive invariant for MongoRaftReconfig that is formalized in TLA+ and formally proved using the TLA+ proof system (TLAPS). We also present a formal TLAPS proof of two key safety properties of MongoRaftReconfig, LeaderCompleteness and StateMachineSafety. To our knowledge, these are the first machine checked inductive invariant and safety proof of a dynamic reconfiguration protocol for a Raft based replication system.

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William Schultz, Ian Dardik, Stavros Tripakis. 2021-09-24. Formal Verification of a Distributed Dynamic Reconfiguration Protocol. https://doi.org/10.1145/3497775.3503688

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