Consensus and Coordination in Practice

Explain the Raft consensus algorithm's mechanisms for leader election, log replication, and safety, and contrast its approach with Paxos.

Apply leader election patterns using a consensus-based coordination service like ZooKeeper or etcd.

Compare distributed locking approaches (e.g., database locks, Redis Redlock, ZooKeeper) and analyze their respective failure modes.

Articulate the PACELC theorem and use it to reason about system design trade-offs beyond the CAP theorem.