What is HAProxy and why it is used?

HAProxy makes your web application highly available, meaning that if you place it in your network in front of two or more web application servers, HAProxy will relay traffic to those servers in roughly equal volume. That way, if some of your servers go offline, HAProxy will simply route traffic away from them towards the healthy servers. The term for this is "load balancing", and HAProxy is a popular load balancer that you can install onto Linux. Of course, it offers additional features related to security, monitoring, routing, and traffic management.