Load balancing Web Application with HA Proxy

In previous post, I have demonstrated how to use NGINX as the load balancer to devide load between application servers. Beside NginX, another popular software load balancer is HAProxy. HAProxy supports for Layer 4 (TCP) and Layer 7 (HTTP) protocol for load balancing. HAProxy Community is an open source, so you can use it for free. In this post, I wll show how to utilize HAProxy as a load balancer for load balancing the traffic between application servers.

For my environment, I have set up as following

• Server 1 : OS Ubuntu 20.4 LTS, Application Server Wildfly 10.1.0 Final
• Server 2 : OS Ubuntu 20.4 LTS, Application Server Wildfly 10.1.0 Final
• Server 3 : OS Ubuntu 20.4 LTS, HA Proxy Community Edition version 2.4

Table Contents

For the contents of this post, I have arranged as below.

1. Install HA Proxy on Ubuntu Server
2. Configuring HA Proxy as Load Balancer
3. Testing HA Proxy for Load Balancing
4. Reference

Let's see, How I have implemented the system as following.

1. Install HA Proxy on Ubuntu Server

First, I will update my repository's mirror.

Update Repository's Mirror

$sudo sed -i 's|http://us.|http://|g' /etc/apt/sources.list
$sudo apt update

To create load balancing by using HA Proxy, I firstly need to installl HA Proxy into my server. Installing HA Proxy is very easy, you could proceed as below.

Install HAProxy

$sudo apt install haproxy

Once you finished installing HAProxy, you could check version of HAProxy as below.

Check Version of HAProxy

$ haproxy -v
HA-Proxy version 2.0.13-2ubuntu0.3 2021/08/27 - https://haproxy.org/    

2. Configuring HA Proxy as Load Balancer

Next is to configure HA prox to route traffic from the client to each web application server. For my set up, I will apply simple routing algorithm like roundrobin to round the request to backend server. You can use others routing algorithms base on your requirements or enviroment's restriction. Below is how I configure my HAProxy.

Configuring HAProxy (Roundrobin)

$ sudo less /etc/haproxy/haproxy.cfg
global
        log /dev/log    local0
        log /dev/log    local1 notice
        chroot /var/lib/haproxy
        stats socket /run/haproxy/admin.sock mode 660 level admin expose-fd listeners
        stats timeout 30s
        user haproxy
        group haproxy
        daemon

        # Default SSL material locations
        ca-base /etc/ssl/certs
        crt-base /etc/ssl/private

        # See: https://ssl-config.mozilla.org/#server=haproxy&server-version=2.0.3&config=intermediate
        ssl-default-bind-ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384
        ssl-default-bind-ciphersuites TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256
        ssl-default-bind-options ssl-min-ver TLSv1.2 no-tls-tickets

defaults
        log     global
        mode    http
        option  httplog
        option  dontlognull
        timeout connect 5000
        timeout client  50000
        timeout server  50000
        errorfile 400 /etc/haproxy/errors/400.http
        errorfile 403 /etc/haproxy/errors/403.http
        errorfile 408 /etc/haproxy/errors/408.http
        errorfile 500 /etc/haproxy/errors/500.http
        errorfile 502 /etc/haproxy/errors/502.http
        errorfile 503 /etc/haproxy/errors/503.http
        errorfile 504 /etc/haproxy/errors/504.http

# HAproxy for web servers
frontend web-frontend
   bind *:80
   mode http
   default_backend web-backend

backend web-backend
   balance roundrobin
   server wildfly01 192.168.0.9:8080 check
   server wildfly02 192.168.0.11:8080 check

listen stats
    bind :32600
    stats enable
    stats uri /
    stats hide-version
    stats auth ha_proxy_admin:EXAMPLE_PASSWORD

After configuring the HAProxy, I need to restart my HAProxy

Restarting HAProxy

$ sudo systemctl retart haproxy

3. Testing HA Proxy for Load Balancing

Now, I will test my haproxy loading server by accessing to the application server through HAProxy via http://192.168.0.10/java-ee-haproxy-web-01/ . You can see as following that your request has been routed thought server 1 and Server 2.

Fig 1. Routing Result

4. Reference

1. How to install HAProxy Load Balancer on Ubuntu
2. Ubuntu Changing Mirror