4 / 4 Deploys, Canary & Rollback

The Door Swings Back

A blue-green cutover moves 100 percent of traffic to green at 14:00. Both environments share one production database. At 14:25 a serious bug is found and traffic is switched back to blue, but blue now throws errors on rows created during those 25 minutes. What does this reveal?

A

Blue should have been shut down at cutover, because an idle fleet on stale code produced the inconsistency

B

Blue-green needs a separate database per environment, and sharing a single one defeats the point of the pattern

C

Blue-green rolls back traffic, not data, so green's writes must stay readable by blue for the rollback window

D

The cutover should have been gradual, since an instant switch of all traffic is what let bad rows accumulate