Setup HAProxy (loadbalancing) on CentOS7

This guide looks into how to setup HAProxy on CentOS7. HAProxy offers load balanced services to HTTP and TCP-based services, such as internet-connected services and web-based applications.

In Apr 2013, we looked into how to Setup Load-Balancing Cluster with LVS and Piranha on Centos 6. This time round for CentOS7, we will setup HAProxy Loadbalancing Cluster as this is shipped with CentOS7.

Setup:
1. HAProxy Server at 192.168.1.3
2. LB Virtual IP to use 192.168.1.3
3. Web1 at 192.168.1.9
4. Web2 at 192.168.1.10

For all the servers, lets (temporary) remove the firewall and selinux.

systemctl stop firewalld
systemctl disable firewalld
vi /etc/selinux/config

disabled

reboot

Lets start, login to HAProxy Server:

yum install haproxy

vi /etc/haproxy/haproxy.cfg

#---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
global
    # to have these messages end up in /var/log/haproxy.log you will
    # need to:
    #
    # 1) configure syslog to accept network log events.  This is done
    #    by adding the '-r' option to the SYSLOGD_OPTIONS in
    #    /etc/sysconfig/syslog
    #
    # 2) configure local2 events to go to the /var/log/haproxy.log
    #   file. A line like the following can be added to
    #   /etc/sysconfig/syslog
    #
    #    local2.*                       /var/log/haproxy.log
    #
    log         127.0.0.1 local2

    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon

    # turn on stats unix socket
    stats socket /var/lib/haproxy/stats

#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#---------------------------------------------------------------------
defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 3
    timeout http-request    10s
    timeout queue           1m
    timeout connect         10s
    timeout client          1m
    timeout server          1m
    timeout http-keep-alive 10s
    timeout check           10s
    maxconn                 3000

#---------------------------------------------------------------------
# main frontend which proxys to the backends
#---------------------------------------------------------------------
frontend LB
   bind 192.168.1.3:80
   reqadd X-Forwarded-Proto:\ http
   default_backend LB

#---------------------------------------------------------------------
# round robin balancing between the various backends
#---------------------------------------------------------------------
backend LB 192.168.1.3:80
   mode http
   stats enable
   stats hide-version
   stats uri /stats
   stats realm Haproxy\ Statistics
   stats auth admin:pass4325    # HAProxy Statistic username/password
   balance roundrobin           # Load balancing to use round-robin
   option httpchk
   option httpclose
   option forwardfor
   cookie LB insert
   server web1 192.168.1.9:80  check  # backend server.
   server web2 192.168.1.10:80 check  # backend server.

We shell enable the service and start the service:

systemctl enable haproxy
systemctl start haproxy

At Webserver create a test page.

vi /var/www/html/p.html

192.168.1.9 (To display Webserver IP address)

systemctl restart httpd

To access the statistic page, navigate to the HAProxy ip/stats,login with the username and pass as states in haproxy.cfg.