Consensus
The process of getting multiple nodes in a distributed system to agree on a single value. The foundation of distributed databases and coordination services.
What is Consensus?
The process of getting multiple nodes in a distributed system to agree on a single value. The foundation of distributed databases and coordination services.
Consensus is a advanced concept that sits in the Distributed Systems Core area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.
If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "Consensus" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.
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Full interactive lesson with diagrams, code examples, real-world references, and a quiz.
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See also
Related glossary terms you might want to look up next.
Paxos
A family of protocols for solving consensus in unreliable networks. Famously difficult to understand but mathematically proven correct.
Raft
A consensus algorithm designed to be understandable. Uses leader election and log replication. Powers etcd (used by Kubernetes) and CockroachDB.
Leader Election
The process of choosing one node in a cluster to coordinate actions. If the leader fails, a new one is elected. Used by Kafka, ZooKeeper, and etcd.