Elastic Load Balancer

Elastic Load Balancer (ELB) is a service that distributes user requests to multiple EC2 instances. By distributing the load, we ensure that our EC2 instances are properly utilized and share the same amount of load between different instances, so that no single instance is over-utilized or under-utilized. We can attach an EC2 instance to the load balancer as and when required. The ELB health check feature monitors the EC2 instance to check that application is up and running so that it can route requests. If the health check fails, ELB marks the EC2 instance as out-of-service so those new requests are not routed to those instances.

For high-availability applications, ELB can be associated with the Auto Scaling group, which can attach a new instance in the event of heavy traffic or remove the instance in the event of failure or low traffic. The auto-scaling group registers the new instance to be added in ELB or is used to remove any instance from ELB.

There are three types...