Configure load balancing for the application tier in a three-tier app where the web tier uses an external HTTP(S) load balancer.

The correct approach is to create a new internal HTTP(S) load balancer for the application tier. In a three-tier architecture, the web tier typically faces external traffic, while the application tier processes requests from the web tier and communicates with the database tier. An internal load balancer is ideal for distributing traffic within your Virtual Private Cloud (VPC) network, providing high availability and scalability for your application servers without exposing them directly to the internet. Adding a forwarding rule or a URL map to the existing external load balancer is incorrect because external load balancers are designed for internet-facing traffic and would expose your internal application tier to the public. Enabling equal-cost multi-path routing on application servers is a network routing technique, not a load balancing solution for application-level traffic distribution.