AWS has launched a new Application Load Balancer option on ELB. This option runs at Layer 7 and supports a number of advanced features. The original option is now knon as Classic Load Balancer, is still available to you and continues to offer Layer 4 and Layer 7 functionality.
- Layer 7 Load Balancing, ie you can redirect the traffic such as /api /admin to only a specific instance / group of instances.
- The hourly rate for the use of an Application Load Balancer is 10% lower than the cost of a Classic Load Balancer.
Application Load Balancers support content-based routing, and supports applications that run in containers. They support a pair of industry-standard protocols (WebSocket and HTTP/2) and also provide additional visibility into the health of the target instances and containers. Web sites and mobile apps, running in containers or on EC2 instances, will benefit from the use of Application Load Balancers.
A Layer 7 LB can inspect the packets, and see what is inside. So if you want to redirect any traffic like /api to a specific server, you can now do so with the Application LB.
For more information, read the Official Blog