Terraform AWS Project Documentation

Overview

This Terraform script is designed to create an AWS infrastructure for a simple web application. The infrastructure includes a Virtual Private Cloud (VPC), two subnets in different availability zones, an Internet Gateway, a Route Table, a Security Group, an S3 bucket, two EC2 instances, and an Application Load Balancer (ALB).

Prerequisites

1. AWS CLI configured with the necessary credentials.
2. Terraform installed on your machine.

Project Structure

• main.tf: Defines the main infrastructure components.
• variables.tf: Defines input variables used in the script.
• userdata.sh: User data script for the first EC2 instance.
• userdata1.sh: User data script for the second EC2 instance.

Configuration

VPC

• Resource: aws_vpc.myvpc
  • Creates a Virtual Private Cloud (VPC) with the specified CIDR block.

Subnets

• Resources: aws_subnet.subnet1 and aws_subnet.subnet2
  • Creates two subnets in different availability zones within the VPC.

Internet Gateway

• Resource: aws_internet_gateway.igw
  • Attaches an Internet Gateway to the VPC for internet access.

Route Table

• Resources: aws_route_table.RT, aws_route_table_association.rta1, and aws_route_table_association.rta2
  • Creates a route table and associates it with the subnets for routing internet-bound traffic through the Internet Gateway.

Security Group

• Resource: aws_security_group.websg
  • Creates a security group to control inbound and outbound traffic for the EC2 instances.
  • Allows inbound traffic on ports 80 (HTTP) and 22 (SSH).
  • Allows all outbound traffic.

S3 Bucket

• Resource: aws_s3_bucket.example
  • Creates an S3 bucket for storing application data.

EC2 Instances

• Resources: aws_instance.webserver1 and aws_instance.webserver2
  • Creates two EC2 instances with specified AMI, instance type, security group, and subnet.
  • Attaches user data scripts for additional configuration.

Application Load Balancer (ALB)

• Resources: aws_lb.myalb, aws_lb_listener.listener, aws_lb_target_group.tg, aws_lb_target_group_attachment.attach1, and aws_lb_target_group_attachment.attach2
  • Creates an Application Load Balancer (ALB) with a listener forwarding traffic to the target group.
  • Associates the ALB with the security group and subnets.
  • Configures health checks for the target group.
  • Attaches EC2 instances to the target group.

Outputs

• Output: loadbalancerdns
  • Displays the DNS name of the created ALB for accessing the web application. The two different webpages showing that the load balancing is working properly.

Usage

1. Ran terraform init to initialize the working directory.
2. Ran terraform plan to see what the changes and infra will be made.
3. Ran terraform apply to create the AWS infrastructure.
4. Confirmed the changes by typing yes when prompted.
5. After completion, the DNS name of the ALB is displayed in the output.

Clean Up

To destroy the created infrastructure, run:

terraform destroy

Confirm the destruction by typing yes when prompted.

Note

• Ensure that sensitive information such as AWS credentials and private keys are handled securely.
• Review the AWS regions, availability zones, and AMI IDs based on your requirements.

References

• Terraform AWS Provider Documentation