How to Setup HAProxy Load Balancing on Ubuntu & LinuxMint

HAProxy is a very fast and reliable solution for high availability, load balancing, It supports TCP and HTTP-based applications. Now a days maximizing websites up-time is very crucial for heavy traffic websites. This is not possible with single server setup. Then we need some high availability environment which can easily manage with single server failure.
haproxy-setup-diagram
This article will help you to setup HAProxy load balancing environment on Ubuntu, Debian and LinuxMint. This will configure a Layer 4 Load Balancing (Transport Layer). Which will balance load and transfer requests to different-2 servers based on IP address and port numbers.

Network Details –

Below is our network server. There are 3 web servers running with Apache2 and listening on port 80 and one HAProxy server.
Web Server Details:  Server 1:    web1.example.com     192.168.1.101 Server 2:    web2.example.com     192.168.1.102 Server 3:    web3.example.com     192.168.1.103  HAProxy Server:   HAProxy:     haproxy              192.168.1.12 

Step 1 – Install HAProxy

Now start the setup. SSH to your haproxy server as privileged user and install HAProxy using following commands.
$ sudo add-apt-repository ppa:vbernat/haproxy-1.5 $ sudo apt-get update $ sudo apt-get install haproxy 

Step 2 – Load Balancing Configuration with HAProxy

Now edit haproxy default configuration file /etc/haproxy/haproxy.cfg and start configuration.
# vi /etc/haproxy/haproxy.cfg 

Default Settings:

You will find some default configuration like below. If you don’t have enough idea about this, you can keep as it is.
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   # Default SSL material locations  ca-base /etc/ssl/certs  crt-base /etc/ssl/private   # Default ciphers to use on SSL-enabled listening sockets.  # For more information, see ciphers(1SSL). This list is from:  #  https://hynek.me/articles/hardening-your-web-servers-ssl-ciphers/  ssl-default-bind-ciphers ECDH+AESGCM:DH+AESGCM:ECDH+AES256::RSA+AES:RSA+3DES:!aNULL:!MD5:!DSS  ssl-default-bind-options no-sslv3  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 

Adding HAProxy Listener:

Now tell HAProxy to where to listen for new connections. As per below configuration HAProxy will listed on port 80 of 192.168.1.12 ip address.
frontend Local_Server     bind 192.168.1.12:80     mode http     default_backend My_Web_Servers 

Add Backend Web Servers:

As per above configuration haproxy is now listening on port 80. Now define the backend web servers where HAProxy send the request.
backend nodes     mode http     balance roundrobin     option forwardfor     http-request set-header X-Forwarded-Port %[dst_port]     http-request add-header X-Forwarded-Proto https if { ssl_fc }     option httpchk HEAD / HTTP/1.1rnHost:localhost     server web1.example.com  192.168.1.101:80     server web2.example.com  192.168.1.102:80     server web3.example.com  192.168.1.103:80 

Enable HAProxy Stats (Optional)

Now if you want you can enable Haproxy statistics by adding following configuration in HAProxy configuration file.
listen stats *:1936     stats enable     stats hide-version     stats refresh 30s     stats show-node     stats auth username:password     stats uri  /stats 

Step 3 – Final HAProxy Configuration File

The final configuration file may look like below .
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   # Default SSL material locations  ca-base /etc/ssl/certs  crt-base /etc/ssl/private   # Default ciphers to use on SSL-enabled listening sockets.  # For more information, see ciphers(1SSL). This list is from:  #  https://hynek.me/articles/hardening-your-web-servers-ssl-ciphers/  ssl-default-bind-ciphers ECDH+AESGCM:DH+AESGCM:ECDH+AES256::RSA+AES:RSA+3DES:!aNULL:!MD5:!DSS  ssl-default-bind-options no-sslv3  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  frontend Local_Server     bind 192.168.1.12:80     mode http     default_backend My_Web_Servers  backend My_Web_Servers     mode http     balance roundrobin     option forwardfor     http-request set-header X-Forwarded-Port %[dst_port]     http-request add-header X-Forwarded-Proto https if { ssl_fc }     option httpchk HEAD / HTTP/1.1rnHost:localhost     server web1.example.com  192.168.1.101:80     server web2.example.com  192.168.1.102:80     server web3.example.com  192.168.1.103:80  listen stats *:1936     stats enable     stats hide-version     stats refresh 30s     stats show-node     stats auth username:password     stats uri  /stats 

Step 4 – Restart HAProxy

Now you have made all necessary changes in your HAProxy server. Now verify configuration file before restarting service using following command.
$ haproxy -c -f /etc/haproxy/haproxy.cfg 
If above command returned output as configuration file is valid then restart HAProxy service
$ sudo service haproxy restart 

Step 5 – Verify HAProxy Setting

At this stage we have full functional HAProxy setup. At each web server node I have a demo index.html page showing servers hostname, So we can easily differentiate between servers web pages.
Now access port 80 on ip 192.168.0.12 (as configured above) in web browser and hit refresh. You will see that HAProxy is sending requests to backend server one by one (as per round robin algorithm).
haproxy-web1
haproxy-web2
haproxy-web3
With each refresh you can that HAProxy is sending request one by one to backend server.
Reference: http://www.haproxy.org/download/1.5/doc/configuration.txt

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