Distributed Runtime Verification Under Partial Synchrony

In this paper, we study the problem of runtime verification of distributed applications that do not share a global clock with respect to specifications in the linear temporal logics (LTL). Our proposed method distinguishes from the existing work in three novel ways. First, we make a practical assumption that the distributed system under scrutiny is augmented with a clock synchronization algorithm that guarantees bounded clock skew among all processes. Second, we do not make any assumption about the structure of predicates that form LTL formulas. This relaxation allows us to monitor a wide range of applications that was not possible before. Subsequently, we propose a distributed monitoring algorithm by employing SMT solving techniques. Third, given the fact that distributed applications nowadays run on massive cloud services, we extend our solution to a parallel monitoring algorithm to utilize the available computing infrastructure. We report on rigorous synthetic as well as real-world case studies and demonstrate that scalable online monitoring of distributed applications is within our reach

DECENT: A Benchmark for Decentralized Enforcement

International audienceDECENT is a benchmark for evaluating decentralized enforcement. It implements two enforcement algorithms that differ in their strategy for correcting the execution: the first one explores all alternatives to perform a globally optimal correction, while the second follows an incremental strategy based on locally optimal choices. Decent allows comparing these algorithms with a centralized enforcement algorithm in terms of computational metrics and metrics for decentralized monitoring such as the number and size of messages or the required computation on each component. Our experiments show that (i) the number of messages sent and the internal memory usage is much smaller with decentralized algorithms (ii) the locally optimal algorithm performs closely to the globally optimal one