AWS ELB

Amazon Elastic Load Balancers (ELB) are responsible for distributing the traffic across multiple EC2 instances. The users, at first connect to the load balancer and then it redirects the traffic to the instance. Then, the response obtained is sent back to the user by the load balancer.

It ensures that multiple users cannot connect to the same EC2 instance, for the purpose that there should be a load distribution across multiple instances, thereby creating a balance, and thus the name- load balancer. It is convenient to seamlessly handle the instance failures using ELBs. ELBs perform regular instance heath-checks, to ensure proper functioning of the instances. If any instance is found unhealthy, then they redirect the traffic to the healthy instance.

ELBs can operate across various availability zones. This signifies a parallel-working of multiple instances across the zones, making the application highly available. They also separate the public traffic and the private traffic. The application load balancers (ALBs) allow us to manage multiple HTTP applications across machines. These balancers also have a port-mapping feature, using which the load can be transferred to the dynamic port. For managing the TCP traffic, we have the network load balancers too.

All load balancers have got a health-check capability and application load balancers, in particular, are a great fit for Docker.