One of the key requirements of running highly available instances in the cloud is the ability to distribute traffic among a set of instances serving the same content. This can be achieved through load balancing. The AWS environment provides a load balancer as a service solution. We will look at the AWS Elastic Load Balancing (ELB) service and learn how to design and build an ELB deployment.

The following topics will be covered in this chapter:

• The AWS Elastic Load Balancing service
• Maintaining session state
• Building an ELB for EC2 instances