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Thoughts on engineering, design, and building great products.
Backing Up etcd and Rotating Certificates
etcd holds all of the cluster's state; lose it and you lose the cluster. Part XIII opens at exactly the scariest spot when things break. We take an etcd snapshot, verify it's valid, and restore it into a fresh data directory to prove the snapshot is usable — all without touching the running etcd. Then we inspect the expiry of the certificate set built in Article 4 and discuss rotating them before they expire.
etcd: Quorum, Raft, and Standing Up a Three-Node Cluster
The first control plane component, and the foundation for everything above it: etcd. This article explains what etcd stores, why it needs an odd number of nodes, and what quorum means via the Raft algorithm — then stands up a three-node etcd cluster on the controllers with TLS, and verifies the leader and cluster health.