Question

A retail company runs a stateful order-management application on Compute Engine behind a global external load balancer, backed by a Cloud SQL for PostgreSQL instance. The engineering team wants to adopt a deployment process that lets them release a new application version with a backward-incompatible database schema change while guaranteeing near-instant rollback if production monitoring detects elevated error rates. Business stakeholders require that customer transactions never be lost during the release and that any rollback take effect within seconds. Which release strategy best satisfies these technical and business requirements?

Accepted Answer

Use an expand-and-contract (backward-compatible) schema migration, deploy the new version to a parallel green environment sharing the same database, and shift traffic via the load balancer with the ability to switch back instantly.

Answer

Perform an in-place rolling update of the instance group and apply the schema change directly to the production database before the new code deploys.

Answer

Provision an entirely separate blue-green stack including a cloned Cloud SQL database, cut all traffic to green, then reconcile the two databases after go-live.

Answer

Take the application offline during a maintenance window, apply the destructive schema change, deploy the new version, and restore service once validation completes.