If we rollback with kubectl rollout undo the pods in the newest replicaset are deleted, and pods in an older replicaset are spun back up, rolling back the upgrade.
But there’s a potential problem here. What happens if that old replicaset is deleted?
If that happens, we wouldn’t be able to rollback the upgrade. Well we wouldn’t be able to roll it back with kubectl rollout undo, but what happens if we’re using Helm?
Read on to learn how the whole thing works.