Capstone - The Zero-Downtime Migration

1. How This Capstone Works

Production migrations are often more dangerous than feature releases because they alter stored data. In this scenario, a continuously available system writes the changing data 400 times each second. The capstone completes one migration under two rules from this module. The first rule is the deploy/release split. The second requires routine rollback at every stage, including stages where a direct reversal initially appears impossible. Those stages must be redesigned until safe reversal exists.