GitHub repository

What is this?

A protocol of quorum-based totally ordered broadcast crashes resilient based on a coordinator selected via ring election. It is the project for the course Distributed Systems at UniTN.

Goal

Implement the protocol and build an actor-based environment in which the protocol can be tested. On the protocol:

• The network consists of various replicas, a coordinator and several clients.
• The clients can make read and write requests on a shared variable among the replicas, sequential consistency must be granted.
• Once a replica receives a write request the coordinator asks around to commit or not the changes (2PC fashion).
• If the coordinator crashes the nodes organise themselves in a virtual ring and elect a new coordinator.
• Replicas can crash too, but no election is held.

What did we do?

We implemented the protocol using the framework akka. The application provides modularity among the number of replicas and clients and the duration of the various communication timeouts. The application provides a multi-level log system by which a manager can verify the correctness of the protocol itself.