Install and Configure HAProxy on CentOS/RHEL 5/6

HAProxy is a very fast and reliable solution for high availability, load balancing, It supports TCP and HTTP-based applications. Now a days most of websites need 99.999% uptime for there site, which are not possible with single server setup. Then we need some high availability environment which can easily manage with single server failure.

This article will help you to install HAProxy on CentOS, RHEL servers and will configure a Layer 4 Load Balancing (Transport Layer). Which will balance load and transfer requests to different-2 servers based on IP address and port numbers.

Setup Instructions:

Step 1: Setup Yum Repository

CentOS/RHEL 5 users required to add EPEL repository in order to install HAProxy packages. For CentOS 6 HAProxy packages are available under base repository, So there are no need to add any repository for them.

On CentOS/RHEL 5:

# rpm -Uvh http://dl.fedoraproject.org/pub/epel/5/i386/epel-release-5-4.noarch.rpm

Step 2: Install HAProxy

Install HAProxy package using yum package manager from command line interface using following comamnd.

# yum install haproxy

Step 3: Configure HAProxy

Update your HAProxy configuration file /etc/haproxy/haproxy.cfg as per your requirement, You may also use below given configuration file as an example of setup and modify it.

# vim /etc/haproxy/haproxy.cfg

[ Update red mark values as per your network setup ]

global
        log 127.0.0.1   local0
        log 127.0.0.1   local1 debug
        maxconn   45000 # Total Max Connections. This is dependent on ulimit
        daemon
        nbproc      1 # Number of processing cores. Dual Dual-core Opteron is 4 cores for example.
defaults
        timeout server 86400000
        timeout connect 86400000
        timeout client 86400000
        timeout queue   1000s

# [HTTP Site Configuration]
listen  http_web 192.168.10.10:80
        mode http
        balance roundrobin  # Load Balancing algorithm
        option httpchk
        option forwardfor
        server server1 192.168.10.100:80 weight 1 maxconn 512 check
        server server2 192.168.10.101:80 weight 1 maxconn 512 check

# [HTTPS Site Configuration]
listen  https_web 192.168.10.10:443
        mode tcp
        balance source# Load Balancing algorithm
        reqadd X-Forwarded-Proto:\ http
        server server1 192.168.10.100:443 weight 1 maxconn 512 check
        server server2 192.168.10.101:443 weight 1 maxconn 512 check

Change the ips in configuration file as per your network setup. In HTTP Site Configuration section if any request on ip 192.168.10.10 on port 80, this will be redirected to port 80 of 192.168.10.100 or 192.168.10.101 servers. Similarly in HTTPS Site Configuration if any request on ip 192.168.10.10 on port 443, this will be redirected to port 443 of 192.168.10.100 or 192.168.10.101 servers.

You also need to make few changes in configuration file as per your system configuration.

nbproc <value>    # Number of processing cores in your system.
mode <value>      #  'http' for http site and 'tcp' for https site
balance <value>   # Type of load balancing like 'source', 'roundrobin' etc.

Step 4: Start HAProxy Service

Start HAProxy service using following command, also configure it to auto start on system boot.

# service haproxy start
# chkconfig haproxy on

And You have done it.

HAProxy Stats provides a lot of information about data transfer, total connection, server state etc. After installing HAProxy if you want to view HAProxy stats in your web browser, You can easily configure it by making few changes in your HAProxy configuration using following steps.

tep 1: Enable Stats in HAProxy

To enable stats edit your haproxy configuration file and add below entry after defaults section.

listen  stats   192.168.10.10:1936
        mode            http
        log             global

        maxconn 10

        clitimeout      100s
        srvtimeout      100s
        contimeout      100s
        timeout queue   100s

        stats enable
        stats hide-version
        stats refresh 30s
        stats show-node
        stats auth admin:password
        stats uri  /haproxy?stats

Step 2: Access HAProxy Stats

Your can access HAProxy stats using following url. Change ip with your haproxy server ip address.

 URL: http://192.168.10.10:1936/haproxy?stats
 Login user: admin
 Login password: password

Step 3: Change Login Details

If you want to changed login details of HAProxy stats, edit your configuration and update “stats auth” value like below

 stats auth  username:password

Save configuration file and restart HAProxy to update service.

Step 4: Change HAProxy Stats URL

To change url of haproxy stats edit configuration file and update following value.

stats uri  /ha-stats
or
stats uri  /stats

Save configuration file and restart HAProxy to update service. Now you can access url likehttp://192.168.10.10:1936/ha-stats or http://192.168.10.10:1936/stats.

Haproxy stats configuration has been completed successfully.