Blue/Green Deploy With ALB and Automatic Rollback
In-place deploys have a window where a machine is offline. Blue/green avoids it: stand up a new fleet (green) in parallel, validate it, then shift traffic over with a load balancer — blue stays intact for an instant return. This article builds an ALB, switches the deployment group to blue/green, runs it for real (including a very realistic IAM error), and configures automatic rollback per CloudWatch alarm.