The shop now runs on two instances, web-1 in us-east-1a and web-2 in us-east-1b, both in the security group web-sg. Each serves its page on / and answers /health once the app is up. Customers still need one address.

1. Keep the default VPC's id in VPC, the subnet of us-east-1a in SUBNET_A and of us-east-1b in SUBNET_B, and the two instances' ids in WEB1 and WEB2.
2. Create a security group alb-sg for the load balancer, open on port 80 to the world, and keep its id in ALB_SG.
3. Create a target group web-tg for the two servers on port 80, register both, and set its health check to ask /health every 10 seconds, healthy after 2 passes.
4. Create the load balancer market-alb in both subnets with alb-sg, and a listener on port 80 that forwards to web-tg. Wait until it is active.
5. Check the targets' health. Read the reason they give, fix what causes it, and check again until both are healthy.
6. Fetch the load balancer's DNS name a few times and see both servers answer.