Step-by-Step HAProxy Deployment and Configuration Guide for Load Balancing

HAProxy Deployment Configuration

Topology diagram

Explanation

haproxy server IP: 172.16.253.200/16 (external), 192.168.29.140/24 (internal)
Blog server group IP: 192.168.29.130/24, 192.168.29.131/24
Website server group IP: 192.168.29.120/24, 192.168.29.121/24
Default server group IP: 192.168.29.110/24, 192.168.29.111/24

HAProxy Host Configuration

# yum install haproxy -y
# vim /etc/haproxy/haproxy.cfg

1. Global Section

Sets global process‑level parameters, often related to OS configuration.

global
    log 127.0.0.1 local2 info   ## global log config
    chroot /var/lib/haproxy
    pidfile /var/run/haproxy.pid ## PID file
    maxconn 4000                ## max concurrent connections
    user haproxy                ## run as user
    group haproxy               ## run as group
    daemon                      ## run in background
    stats socket /var/lib/haproxy/stats

2. Defaults Section

Defines default parameters that are inherited by frontend, backend, and listen sections unless overridden.

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 5s
    timeout client 10s
    timeout server 10s
    timeout http-keep-alive 10s
    timeout check 2s
    maxconn 3000

3. Listen Section

Combines frontend and backend functionality for the admin statistics page.

listen admin_stats
    bind 0.0.0.0:19088          ## stats page IP and port
    mode http
    log 127.0.0.1 local2 err
    stats refresh 30s          ## auto‑refresh interval
    stats uri /haproxy-status  ## URL path for stats page
    stats realm welcome login Haproxy
    stats auth admin:admin     ## credentials
    stats hide-version
    stats admin if TRUE

4. Frontend Section

Defines the front‑end virtual node that receives client requests and selects a backend via ACL rules.

frontend www
    bind *:80
    mode http
    option httplog
    option forwardfor
    option httpclose
    log global

ACL rules enable intelligent load balancing:

acl host_www hdr_reg(host) -i ^(www.tb.com|tb.com)
acl host_blog hdr_beg(host) -i blog.
use_backend server_www if host_www
use_backend server_blog if host_blog
default_backend server_default

5. Backend Sections

Configure backend server pools for default, www, and blog services.

backend server_default
    mode http
    option redispatch
    option abortonclose
    balance roundrobin
    cookie SERVERID
    option httpchk GET /check_status.html
    server default1 192.168.29.110:80 cookie default1 weight 2 check inter 2000 rise 2 fall 3
    server default2 192.168.29.111:80 cookie default2 weight 2 check inter 2000 rise 2 fall 3

backend server_www
    mode http
    option redispatch
    option abortonclose
    balance source
    cookie SERVERID
    option httpchk GET /check_status.jsp
    server www1 192.168.29.120:80 cookie www1 weight 6 check inter 2000 rise 2 fall 3
    server www2 192.168.29.121:80 cookie www2 weight 6 check inter 2000 rise 2 fall 3

backend server_blog
    mode http
    option redispatch
    option abortonclose
    balance roundrobin
    cookie SERVERID
    option httpchk GET /check_blog.php
    server blog1 192.168.29.130:80 cookie blog1 weight 5 check inter 2000 rise 2 fall 3
    server blog2 192.168.29.131:80 cookie blog2 weight 5 check inter 2000 rise 2 fall 3

Backend Server Configuration

1. Default Server

Virtual host and status page setup for 192.168.29.110 and .111.

# vim /etc/httpd/conf.d/vhost.conf
<VirtualHost 192.168.29.110:80>
    DocumentRoot "/data/web1"
    <Directory "/data/web1/">
        Options Indexes FollowSymLinks
        AllowOverride None
        Require all granted
    </Directory>
</VirtualHost>
# echo "This is check_status.page ip:192.168.29.110" > /data/web1/check_status.html
# echo "This is default page ip:192.168.29.110" > /data/web1/index.html

2. Website Server

Configuration for 192.168.29.120 and .121 (www.tb.com).

# vim /etc/httpd/conf.d/vhost.conf
<VirtualHost 192.168.29.120:80>
    DocumentRoot "/data/web1"
    ServerName www.tb.com
    <Directory "/data/web1/">
        Options Indexes FollowSymLinks
        AllowOverride None
        Require all granted
    </Directory>
</VirtualHost>
# echo "This is check_status page ip:192.168.29.120" > /data/web1/check_status.jsp
# echo "This is www page ip:192.168.29.120" > /data/web1/index.html

3. Blog Server Group

Configuration for 192.168.29.130 and .131 (www.blog.tb.com).

# vim /etc/httpd/conf.d/vhost.conf
<VirtualHost 192.168.29.130:80>
    DocumentRoot "/data/web1"
    ServerName www.blog.tb.com
    <Directory "/data/web1/">
        Options Indexes FollowSymLinks
        AllowOverride None
        Require all granted
    </Directory>
</VirtualHost>
# echo "This is check_status page ip:192.168.29.130" > /data/web1/check_blog.php
# echo "This is blog page ip:192.168.29.130" > /data/web1/index.html

Testing

1. Start HAProxy

# systemctl start haproxy

2. Test Website Servers

for i in {1..10}; do curl www.tb.com; done
# All responses show the same IP (192.168.29.120) due to session stickiness.

3. Test Blog Servers

for i in {1..10}; do curl blog.tb.com; done
# Responses alternate between 192.168.29.130 and 192.168.29.131, confirming round‑robin load balancing.

4. Test Default Servers

for i in {1..10}; do curl 172.16.253.200; done
# Responses alternate between 192.168.29.110 and 192.168.29.111.

5. HAProxy Statistics Page

Access http://172.16.253.200:19088/haproxy-status, log in with the configured credentials to view real‑time statistics.