How to Load Balance with HAProxy

Prerequisites

Before configuring HAProxy, make sure you have:

• A dedicated VPS for HAProxy (or run on same VPS)
• Two or more backend web servers
• Root or sudo privileges

Step 1: Install HAProxy

Connect to your HAProxy VPS:

ssh hxroot@YOUR_SERVER_IP -p 22

sudo apt update
sudo apt install haproxy -y

Step 2: Configure HAProxy

Backup default config:

sudo cp /etc/haproxy/haproxy.cfg /etc/haproxy/haproxy.cfg.bak

sudo nano /etc/haproxy/haproxy.cfg

Example for HTTP load balancing:

global
    log /dev/log local0
    maxconn 4096
    user haproxy
    group haproxy

defaults
    log global
    mode http
    option httplog
    option dontlognull
    retries 3
    timeout connect 5000
    timeout client 50000
    timeout server 50000

frontend http_front
    bind *:80
    stats uri /haproxy?stats
    default_backend http_back

backend http_back
    balance roundrobin
    server web1 BACKEND1_IP:80 check
    server web2 BACKEND2_IP:80 check

Step 3: Enable HAProxy

sudo systemctl enable haproxy
sudo systemctl start haproxy

Step 4: Allow Firewall Port

sudo ufw allow 80/tcp

Step 5: Check HAProxy Status

sudo systemctl status haproxy

Step 6: Access Statistics Page

Visit http://YOUR_HAPROXY_IP/haproxy?stats (username: stats, password: stats by default). You can change credentials in config.

Configure HTTPS Load Balancing

Add SSL termination:

frontend https_front
    bind *:443 ssl crt /etc/ssl/certs/haproxy.pem
    default_backend http_back

Generate self-signed or copy your SSL certificate and key into a combined .pem file.

Load Balancing Algorithms

• roundrobin – Distributes equally (default)
• leastconn – Sends to server with fewest connections
• source – Ensures client sticks to same backend (session persistence)

Health Checks Customization

server web1 BACKEND1_IP:80 check inter 2000 rise 2 fall 3

Check every 2 seconds, require 2 successes, mark down after 3 failures.

Test HAProxy

Generate traffic to your HAProxy IP and check statistics page to see distribution.