Application Load Balancer simplifies deployments with support for weighted target groups
Application Load Balancers now support Weighted Target Groups routing. With this launch you will be able to do weighted routing of the traffic forwarded by a rule to multiple target groups. This enables various use cases like blue-green, canary and hybrid deployments without the need for multiple load balancers. It even enables zero-downtime migration between on-premises and cloud or between different compute types like EC2 and Lambda.
Source:: Amazon AWS