While reviewing the CodePipeline, review the stage that triggers Lambda execution to swap the target-group assignments for the listener ports. This stage will be triggered only when the preceeding stage gets an approval.
Blue Target Group is associated with Port 80 that represents Live/Production traffic and Green Target Group is associated with Port 8080 and is available for new version of the Application.
The new version of the application (green environment) can be tested by accessing the load balancer at port 8080, example http://LOAD_BALANCER_URL:8080 .If you want to restrict the traffic ranges accessing beta version of the code, you may modify the Ingress rules here.
To simplify identifying which Target Groups are serving Live traffic, we have added Tags on ALB Target Groups. Target Group IsProduction Tag will say true for Production application.
The diagram below shows the backend mapping of Listener Ports <-> Target-Group being swapped after the approval.