HAProxy stands for High Availability Proxy, is an open-source TCP/HTTP load balancer. In case you are new to the idea of a load balancer, the work of a load balancer is to distribute incoming requests to an array of upstream servers so as no single upstream server is overworked/overloaded by the incoming requests. HAProxy has been reported to be highly efficient and fault tolerant, and it is also claimed that HAProxy has never crashed in a production environment. HAProxy is very configurable, you can chose for a variety of load balancing algorithms like Round-Robin, Source, LeastConn, etc., it also provides support for sticky session, provides detailed logs and monitoring stats. In this article we'll look at installing and setting up a basic HAProxy load balancer. Installing HAProxy Firstly, download the source tarball from HAProxy official website (http://haproxy.1wt.eu/), then untar, build and install: Code: $ tar -zvxf haproxy-1.4.22.tar.gz $ cd haproxy-1.4.22 $ make $ cp haproxy /usr/sbin/haproxy Now, you have built and copied the standalone HAProxy executable to the sbin directory, you can run haproxy as a command. Configuring HAProxy There are lots of configuration options, it can be as easy as the installation or something very complicated, it all depends on your requirements. Here we'll look at a very simple configuration example, I've added comments for easier understanding of the configuration directives, you can find the complete configuration guide on the HAProxy website (http://haproxy.1wt.eu/#docs) You can put the HAProxy configuration file wherever you want, for example I put it in /etc/conf/haproxy.conf Code: ## global options global ## maximum allowed connections maxconn 10000 ## path to the PID file pidfile /var/run/haproxy.pid ## specify to run as a daemon daemon defaults ## conifgure to server HTTP requests mode http ## maintain HTTP requests log option httplog ## add X-Forwarded-For header option forwardfor listen http haproxy.go4expert.com:80 mode tcp option tcplog ## specify algorithm balance roundrobin maxconn 10000 ## specify server array server appserver1 192.168.1.1:80 server appserver2 192.168.1.2:80 To start HAProxy with the configuration issue the following command: Code: $ haproxy -f /etc/conf/haproxy.conf To view the stats, the URL would be haproxy.go4expert.com/haproxy?stats I hope it has been helpful to you, post your experiences so that we all can share and learn.