Configuring a Load Balancer on Ubuntu Server: A Step-by-Step Tutorial

This tutorial will show you how to configure a load balancer on Ubuntu Server.

Introduction

Load balancing is a critical component of modern web applications, allowing them to distribute traffic across multiple servers to improve performance, scalability, and availability. A load balancer acts as a single entry point for client requests and distributes them across multiple servers, ensuring no single server becomes overwhelmed with traffic.

We will use HAProxy, a free and open-source software, to configure a simple round-robin load balancer that distributes traffic across multiple web servers. We will walk you through the installation and configuration process step-by-step, showing you how to configure HAProxy, set up numerous web servers, and test the load balancer to ensure it works correctly. At the end of this tutorial, you will have a fully functional load balancer that can distribute traffic across multiple servers, improving the performance and availability of your web applications.

Prerequisites:

• Two or more Ubuntu servers with Apache installed
• Ubuntu Server with root access
• Basic knowledge of Ubuntu Server and Apache

Configuring a Load Balancer on Ubuntu Server

Step 1: Install HAProxy
First, we need to install HAProxy on Ubuntu Server. Following command:

sudo apt-get install haproxy
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
  haproxy
0 upgraded, 1 newly installed, 0 to remove and 20 not upgraded.
Need to get 436 kB of archives.
After this operation, 1,448 kB of additional disk space will be used.
Get:1 http://us.archive.ubuntu.com/ubuntu bionic/main amd64 haproxy amd64 1.8.8-1ubuntu0.10 [436 kB]
...
Setting up haproxy (1.8.8-1ubuntu0.10) ...
Processing triggers for systemd (237-3ubuntu10.57) ...

Step 2: Configure HAProxy
Next, we need to configure HAProxy to distribute traffic across our web servers. Open the HAProxy configuration file in your favorite text editor:

sudo nano /etc/haproxy/haproxy.cfg

# HAProxy configuration file

global
    log /dev/log local0
    log /dev/log local1 notice
    chroot /var/lib/haproxy
    stats socket /run/haproxy/admin.sock mode 660 level admin
    stats timeout 30s
    user haproxy
    group haproxy
    daemon

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

frontend http_front
    bind *:80
    default_backend web_servers

backend web_servers
    balance roundrobin
    server web1 192.168.56.101:80 check
    server web2 192.168.56.102:80 check

Replace the IP addresses and ports with the IP addresses and ports of your web servers.

Save and close the file.

Step 3: Restart HAProxy
After making changes to the configuration file, we need to restart HAProxy for the changes to take effect:

sudo systemctl restart haproxy

Step 4: Test the Load Balancer. To test the load balancer, open a web browser and navigate to the IP address of your Ubuntu Server. You should be redirected to one of the web servers defined in the HAProxy configuration file.

Refresh the page several times to ensure the load balancer distributes traffic evenly across the web servers.