A load balancer is a device that sits between the user and the server group and acts as an invisible facilitator, ensuring that all resource servers are used equally. In AWS, Elastic Load Balancing (ELB) is a fully managed load balancing service that automatically distributes incoming application traffic to multiple targets and virtual appliances across AWS and on-premises resources. ELB supports the following types of load balancers: Application Load Balancers, Network Load Balancers, Gateway Load Balancers, and Classic Load Balancers.
An Application Load Balancer is used to route HTTP/HTTPS (or Layer 7) traffic and makes routing decisions at the application layer, supports path-based routing, and can route requests to one or more ports on each container instance in your cluster. It automatically distributes incoming traffic across multiple targets, such as EC2 instances, containers, and IP addresses, in one or more Availability Zones, and monitors the health of its registered targets, routing traffic only to the healthy targets.
Using a load balancer increases the availability and fault tolerance of your applications, and you can use ELB to scale modern applications without complex configurations or API gateways.
