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Thoughts on engineering, design, and building great products.
Deployment: rollout and rollback
So far we've only created bare Pods. No one runs production that way — pods are handed to a Deployment, which manages them through a middle layer: the ReplicaSet. This article opens Part IV by digging into that mechanism: changing the image spawns a new ReplicaSet, a rolling update scales it up while scaling the old one down, and the old ReplicaSet is kept at 0 so rollback is one command. Tested step by step on a real cluster, tracing Pod → ReplicaSet → Deployment.
Deployment and ReplicaSet: Keeping Your App Alive
Deployment is the object you use most to run applications: it keeps N pod copies alive (via ReplicaSet), rebuilds them when they die, scales up/down, and updates versions gradually with no downtime — plus rollback. This article proves each property with real commands.