[Day 5] 7. Squid as a Load Balancer

Setup Overview

We are configuring SQUID to act as a load balancer for two Apache Servers on separate machines.

Network Configuration:

• 192.168.80.128: SQUID server (load balancer).
• 192.168.80.129: Apache Server 1.
• 192.168.80.130: Apache Server 2.

Objective:

Distribute traffic between the two Apache servers using SQUID in a round-robin manner.

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Steps to Set Up SQUID as a Load Balancer

1. Install and Configure SQUID on Machine 192.168.80.128

1. Make sure you have already configured squid before, if not then visit Day 4 and configure it accordingly. After configuring Squid, follow the steps written below:

2. Change the Default Port to 80:

   • Open the squid.conf file:

     bashCopy
     sudo nano /etc/squid/squid.conf
     

   • Search for

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     3128

     and replace it with
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     80

     :

     plaintextCopy
     http_port 80 vhost
     

3. Configure Load Balancing:

   • Add the following lines to the

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     squid.conf

     file:

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     cache_peer 192.168.80.129 parent 80 0 no-query originserver round-robin weight=1 name=one
     cache_peer 192.168.80.130 parent 80 0 no-query originserver round-robin weight=1 name=two
     

   • Explanation:

     • cache_peer: Defines backend servers.
     • parent: Indicates that these servers will handle HTTP traffic.
     • round-robin: Distributes traffic equally.
     • weight=1: Ensures equal load distribution.

4. Restart SQUID:

   • Restart the service to apply changes:

     bashCopy
     sudo systemctl restart squid
     sudo systemctl status squid
     

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2. Configure Apache Servers

1. Setup Apache Server 1 on 192.168.80.129:

   • Install Apache (if not already installed):

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     sudo apt-get install apache2
     

   • Create a unique webpage:

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     echo "Welcome to Apache Server 1" | sudo tee /var/www/html/index.html
     

   • Restart Apache:

     bashCopy
     sudo systemctl restart apache2
     

2. Setup Apache Server 2 on 192.168.80.130:

   • Install Apache:

     bashCopy
     sudo apt-get install apache2
     

   • Create a different webpage:

     bashCopy
     echo "Welcome to Apache Server 2" | sudo tee /var/www/html/index.html
     

   • Restart Apache:

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     sudo systemctl restart apache2
     

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3. Test Load Balancing

1. Open a browser and enter the IP address of the SQUID server:

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   http://192.168.80.128
   

2. Verify Round-Robin Behavior:

   • Refresh the browser multiple times.
   • You should see outputs alternating between:
     • "Welcome to Apache Server 1"
     • "Welcome to Apache Server 2"

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Notes

• The vhost option in

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  http_port 80 vhost

  enables virtual hosting, allowing SQUID to handle traffic destined for multiple backends.

• Ensure the Apache servers are accessible on port 80.

• If SQUID doesn’t load balance properly, check the logs for debugging:

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  sudo tail -f /var/log/squid/access.log
  

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