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.  

from Recent Announcements: https://aws.amazon.com/about-aws/whats-new/2019/11/application-load-balancer-simplifies-deployments-support-for-weighted-target-groups/