Assess learners' ability to design and implement fault-tolerant, scalable microservice architectures using consensus algorithms (Raft/Paxos), sharding, replication, and eventual consistency patterns. Tasks include selecting consensus and replication strategies, producing architecture diagrams and pseudocode for leader election/replication and rebalancing, defining consistency and failure-recovery plans, and justifying trade-offs (CAP, latency, throughput) with testing strategies.