We are excited to announce support for session stickiness in Elastic Load Balancing. Until now, the behavior of load balancers has been to route each request independently to the Amazon EC2 instance with the least load. With the stickiness feature, you can configure the load balancer to bind user sessions to specific application instances. All requests coming from the user during the session will be sent to the same application instance. Elastic Load Balancing supports two mechanisms to provide session stickiness: load balancer-generated HTTP cookies, which allow browser-based session lifetimes, and application-generated HTTP cookies, which allow application-specific session lifetimes. You can learn more about this feature by visiting the ELB Developers Guide.