Amazon ELB is a very convenient and easy to setup as a component in the Enterprise Web Applications to balance the incoming web request load to available pool of instances. In addition to this, Amazon ELB also detects the health of instances in the pool and can change the traffic pattern of requests to route them to only healthy instances.
ELB also has facility to enable stickiness in the sessions so that request from the same client is load balanced by the same instance in the pool. An additional use of ELB is to map requests from port HTTP 80 to HTTP port 8080 of the application servers or web servers running on the EC2 instance.
How to setup ELB?Step 1: Click on the create new load balancer button:
Select the application path on the application server to which the ELB will send ping requests to check the health of the instances.
Step 3 : Select the instances to be added to the pool of instances available for load balancing:
Step 4: Confirm the details and click the create button.
This will create the ELB for the pool of EC2 instances and now you can send requests to the ELB on HTTP port 80 from the address bar of your web browser, ELB will forward the request to the ELB and the response will be rendered to the browser.
For more details of Amazon Elastic Load Balancer, visit here - http://aws.amazon.com/elasticloadbalancing/