network-load-balancer

Network Load Balancer Deployment Example

This example has been created by Miha Markočič

This example deploys AWS network infrastructure (VPC and public subnet), three web servers, and a network load balancer:

Network infrastructure:

1. Create a new VPC (10.0.0.0/16)
2. Create one public (10.0.1.0/24) subnet
3. Create internet gateway and associate it with VPC
4. Create a new route table and add a route towards internet gateway for public subnet traffic
5. Create webserver SG (HTTP, HTTPS and SSH from anywhere; HTTP, HTTPS to anywhere)

EC2 instance deployment:

1. Obtain AWS AMI ID for the desired os (Ubuntu Server 20.04 LTS from Canonical)

2. Deploy 3 webserver instances in a created public subnet

3. Update apt-get on each instance using "remote-exec" Terraform provisioner

4. Run Ansible playbook¹ using "local-exec" Terraform provisioner to:

   • Install Apache service on all 3 Ubuntu servers
   • Enable Includes and cgi Apache2 modules
   • Copy .htaccess file with to var/www/html/
   • Enable XBitHack in apache2.conf configuration file
   • Add Includes to the var/www/ directory in apache2.conf
   • Replace index.html file. Replaced html homepage is set to show webserver's ifconfig.
   • Restart Apache service

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¹ Ansible Playbook is run only once with the remote provisioner as there are all 3 webservers in the Ansible inventory. Ansible inventory uses aws_ec2 plugin.

Network Load Balancer

1. Deploy network load balancer with an elastic IP in a public subnet with 3 webserver instances
2. Create 2 load balancer listeners listening to the incoming traffic:
   • Forwarding the incoming HTTP requests on port 80
   • Forwarding the incoming HTTPS requests on port 443
3. Create 2 target groups (HTTP and HTTPS) to distribute the load between the targets
4. Create target group attachments to attach individual instance/node to the desired target group². In this example, all 3 instances (webserver1, webserver2, webserver3) are associated with http and https target group.

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² All targets in the same target group have to run the same service.