Application Load Balancer (ALB)

• Layer 7
• Ideal for HTTP, HTTPS, Websockets traffic
• v2 (2016)
• ALB provides a fixed hostname xxx.region.elb.amazonaws.com
• ALBs do not provide static IPs for access! If you need it check NLBs

Target Groups

• Balance to target groups (applications across machines) -> EC2, ECS, Lambda, IPs,
• Has port mapping feature to redirect to dynamic port in ECS

Routing Table

• Allow routing table to different target groups

• Path

• E.g., /users, /posts

• Hostname

• E.g., one.example.com, two.example.com

• Request Data

• QueryString: ?id=123&order=false
• Headers
• Method
• Source IP

Data redirect

• The application don't receive the IP of the client directly (receives the internal IP of LB instead). Info about the client goes in the headers X-Forwarded-For X-Forwarded-Port X-Forwarded-Proto