Application Load Balancer (ALB)

• An ALB functions at the application layer (the seventh layer of the OSI model).

• After the load balancer receives a request, it evaluates the listener rules in priority order to determine which rule to apply, and then selects a target from the target group for the rule action.

Host conditions

• You can use host conditions to define rules that route requests based on the host name in the host header (also known as host-based routing).

• This enables you to support multiple subdomains and different top-level domains using a single load balancer.

Example hostnames

• example.com

• test.example.com

• hello.example.com

Path conditions

• You can use path conditions to define rules that route requests based on the URL in the request (also known as path-based routing).

• The path pattern is applied only to the path of the URL, not to its query parameters.

Example HTTP path patterns

• /img/*

• /img/*/pics