In this topic we will learn how to install and configure HAProxy 1.4.24 in CentOS 6.
HAproxy is widely used Open Source tcp/http based loadbalancer.And many renowned company also using the HAProxy.Here in this tutorial we will install the latest stable HAProxy version 1.4.24 in CentOS 6.4.

We recommend to install latest stable version 1.4.24, read the below given release note.

Follow the given below steps for HAProxy 1.4.24 installation in CentOS 6.4

Details:

LoadBalancer Server Name = HAProxy
No. of Webserver = 2 (webserver1 and webserver2)
HAProxy IP address = 192.241.190.251
webserver1 IP address = 192.168.122.101
webserver2 IP address = 192.168.122.102
server Health Check File name = healthcheck.txt

Step 1: Login as root and download the HAProxy tarball in Server

yum install wget gcc gcc-c++ autoconf automake make
wget http://haproxy.1wt.eu/download/1.4/src/haproxy-1.4.24.tar.gz

Step 2: Extract the tarball

tar -xvzf haproxy-1.4.24.tar.gz

Step 2: Now compile the HAProxy

cd haproxy-1.4.24

make TARGET=linux26

make install

Step 3: Create haproxy directory in /etc and its config file

mkdir -p /etc/haproxy

Now create a file called haproxy.cfg in /etc/haproxy

Note: In configuration file we have added two webserver named with webserver1 and webserver2.You can add two or more than two webserver in list. Replace the Servername and IP address as per your information.

vi /etc/haproxy/haproxy.cfg

global
        log 127.0.0.1   local0
        log 127.0.0.1   local1 notice
        maxconn 5000
        chroot /var/lib/haproxy
        user haproxy
        group haproxy
        daemon

defaults
        log     global
        mode    http
        option  httplog
        option  dontlognull
        option redispatch
        retries 3
        maxconn 4000
        contimeout      8000
        clitimeout      80000
        srvtimeout      80000

listen LOADBAL  192.241.190.251:80
      mode http
      cookie LOADBAL  insert
      balance roundrobin
      option httpclose
      option forwardfor
      option httpchk HEAD /healthcheck.txt HTTP/1.0
      server webserver1 192.168.122.101:80 cookie webserver1 check
      server webserver2 192.168.122.102:80 cookie webserver2 check
      capture response header Location len 40

listen stats :4997
    mode http
    stats enable
    stats hide-version
    stats realm Haproxy Statistics
    stats uri /
    stats auth scloaduser:your_password
 

Step 3: Now login into both server[webserver1 and webserver2] and create a blank file in its webspace called healthcheck.txt (See the line having “option httpcheck” in configuration)

Here in this example we have two server webserver1 and webserver2.

(a) Login into both server as a root
(b) Our web application path is at /var/www/html/application_name
Hence we are creating a blank file in same path in both server respectively.

touch /var/www/html/application_name/healthcheck.txt

Step 4: Now start the haproxy service in Loadbalancer server a.k.a HAproxy server

haproxy -f /etc/haproxy/haproxy.conf

To stop the haproxy service,first get the pid of haproxy and kill it

ps -ef|grep haproxy

kill -9 pidof_haproxy

Step 5: To get the haproxy dashboard in configuration file below given lines were already added

listen stats 192.241.190.251:4997
    mode http
    stats enable
    stats hide-version
    stats realm Haproxy Statistics
    stats uri /
    stats auth scloaduser:your_password

As per above configuration.

listen stats 192.241.190.251:4997 means in ip address 192.241.190.251 port no. 4997 you can get the haproxy dashboard.
stats auth scloaduser:your_password here you have to mention your haproxy’s dashboard username and password.

To access the HAproxy dahsboard, open the webbrowser and in URL type

http://loadbalancer-ip-address:4997

In our eg. it is

http://192.241.190.251:4997

To enable haproxy logging. Read this post https://sharadchhetri.com/2013/10/16/how-to-enable-logging-of-haproxy-in-rsyslog/