Bounded Rollouts and Guarded Writes

Two quiet failures share a shape: a change that looks fine until the conditions vary. A canary rollout without a fixed rule tells you nothing, and a write that does not check the version it read erases another writer's work. This course covers fixing the rollback rule before the numbers arrive, widening a rollout in steps, guarding a write with the version it read, and rebasing on a rejected write.