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etcd: Kubernetes Source of Truth

etcd is the distributed key-value store that stores all Kubernetes cluster state using Raft consensus.

🎯Key Takeaways
etcd = K8s source of truth (all objects stored here)
Raft quorum: 3 nodes tolerate 1 failure, 5 nodes tolerate 2
etcd is the highest-risk component — back up daily, monitor disk I/O

etcd: Kubernetes Source of Truth

etcd is the distributed key-value store that stores all Kubernetes cluster state using Raft consensus.

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What you'll learn
  • etcd = K8s source of truth (all objects stored here)
  • Raft quorum: 3 nodes tolerate 1 failure, 5 nodes tolerate 2
  • etcd is the highest-risk component — back up daily, monitor disk I/O

How etcd Works

etcd uses Raft consensus algorithm to maintain consistency across 3+ nodes. Raft elects a leader per term; all writes go through the leader and are replicated to followers before committing. etcd stores all K8s objects as protobufs in a hierarchical namespace (/registry/pods, /registry/services, etc.).

Key takeaways

  • etcd = K8s source of truth (all objects stored here)
  • Raft quorum: 3 nodes tolerate 1 failure, 5 nodes tolerate 2
  • etcd is the highest-risk component — back up daily, monitor disk I/O

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