An ECS service behind an ALB needs a replacement task set validated on a test listener before production traffic moves. The team uses an existing CodeDeploy deployment group. Which pattern is appropriate?

1. Use the supported ECS blue/green configuration with the required target groups, listeners, and validation hooks.
2. Use one unrelated health-check URL as proof that the replacement task set was tested.
3. Share all mutable local container files between old and new task versions as the rollback mechanism.
4. Overwrite every running task in place and assume a separate green target exists automatically.