Step 1: Create a test listener
An Amazon ECS deployment with validation tests requires a second listener. This listener is used to serve test traffic to your updated Amazon ECS application in a replacement task set. Your validation tests run against the test traffic.
The listener for your test traffic can use either of your target groups. Use the create-listener AWS CLI command to create a second listener with a default rule that forwards test traffic to port 8080. Use the ARN of your load balancer and the ARN of one of your target groups.
aws elbv2 create-listener --load-balancer-arnyour-load-balancer-arn\ --protocol HTTP --port 8080 \ --default-actions Type=forward,TargetGroupArn=your-target-group-arn--regionyour-aws-region
