How to Setup High-Availability Load Balancer with ‘HAProxy’ to Control Web Server Traffic

HAProxy stands for High Availability proxy. It is a Free and open source application written in C programming Language. HAProxy application is used as TCP/HTTP Load Balancer and for proxy Solutions. The most common use of the HAProxy application is to distribute the workload across multiple servers e.g., web server, database server, etc thus improving the overall performance and reliability of server environment.

The highly efficient and fast application is used by many of the world’s reputed organization which includes but not limited to – Twitter, Reddit, GitHub and Amazon. It is available for Linux, BSD, Solaris and AIX platfor

In this tutorial, we will discuss the process of setting up a high availability load balancer using HAProxy to control the traffic of HTTP-based applications (web servers) by separating requests across multiple servers.

For this article, we’re using the most recent stable release of HAProxy version i.e. 1.5.10 released on December 31st 2014. And also we’re using CentOS 6.5 for this setup, but the below given instructions also works on CentOS/RHEL/Fedora and Ubuntu/Debian distributions.
My Environment Setup
Here our load-balancer HAProxy server having hostname as websrv.tecmintlocal.com with IP address 192.168.0.125.

HAProxy Server Setup

Client Web Servers Setup
The other four machines are up and running with web servers such as Apache.

Step 1: Installing Apache on Client Machines

1. First we have to install Apache in all four server’s and share any one of site, for installing Apache in all four server’s here we going to use following command.

2. After installing Apache web server on all four client machines, you can verify anyone of the server whether Apache is running by accessing it via IP address in browser.

Step 2: Installing HAProxy Server

3. In most of the today’s modern Linux distributions, HAPRoxy can be easily installed from the default base repository using default package manager yum or apt-get.

For example, to install HAProxy on RHEL/CentOS/Fedora and Debian/Ubuntu versions, run the following command. Here I’ve included openssl package too, because we’re going to setup HAProxy with SSL and NON-SSL support.

Note: On Debian Whezzy 7.0, we need to enable the backports repository by adding a new file backports.listunder “/etc/apt/sources.list.d/” directory with the following content.

Next, update the repository database and install HAProxy.

Step 3: Configure HAProxy Logs

4. Next, we need to enable logging feature in HAProxy for future debugging. Open the main HAProxy configuration file ‘/etc/haproxy/haproxy.cfg‘ with your choice of editor.

Next, follow the distro-specific instructions to configure logging feature in HAProxy.
On RHEL/CentOS/Fedora

Under #Global settings, enable the following line.

On Ubuntu/Debian
Under #Global settings, replace the following lines,

With,