Terraform EC2 and Security Group Modules with Apache2

This project guides you through creating a modular Terraform configuration to deploy an EC2 instance with a web server (Apache2) automatically installed and configured.

📦 Introduction

In this project, you will learn how to structure your Terraform code into reusable modules. This is a best practice for managing infrastructure as code, making your configurations more organized, scalable, and easier to maintain.

We will create two main modules:

EC2 Module: Responsible for creating the EC2 instance.
Security Group Module: Responsible for defining the firewall rules for our EC2 instance.

We will also use a UserData script to automatically install and configure Apache2 on the EC2 instance upon launch.

🎯 Project Goals

Understand and implement Terraform modules.
Create a reusable EC2 module.
Create a reusable Security Group module.
Use UserData to bootstrap an EC2 instance with a web server.
Deploy and verify a web server running on AWS.

🛠️ Prerequisites

Before you begin, ensure you have the following:

AWS Account: An active AWS account with the necessary permissions to create EC2 instances and Security Groups.
AWS CLI: The AWS Command Line Interface installed and configured with your credentials. You can check your configuration by running aws configure list.
Terraform: Terraform installed on your local machine. You can verify the installation by running terraform --version.
Basic Linux Knowledge: Familiarity with basic Linux commands.

📂 Project Structure

First, let's set up the directory structure for our project.

1. Create the Project Directory

Open your terminal and create a directory for the project:

mkdir terraform-ec2-apache
cd terraform-ec2-apache

2. Create the Module Directories

Inside the terraform-ec2-apache directory, create directories for your modules:

mkdir -p modules/ec2
mkdir -p modules/security_group

Your project structure should now look like this:

terraform-ec2-apache/
├── modules/
│   ├── ec2/
│   └── security_group/
└── main.tf

🚀 Step-by-Step Guide

Step 1: Create the Security Group Module

This module will define a security group that allows inbound traffic on port 80 (HTTP) and port 22 (SSH).

Create a file named main.tf inside the modules/security_group directory:

nano modules/security_group/main.tf

Add the following code to the file:

resource "aws_security_group" "web_sg" {
  name        = "web-server-sg"
  description = "Allow HTTP and SSH traffic"

  ingress {
    from_port   = 80
    to_port     = 80
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

  ingress {
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

output "security_group_id" {
  value = aws_security_group.web_sg.id
}

Step 2: Create the EC2 Instance Module

This module will define the EC2 instance. It will use the security group created in the previous step.

Create a file named main.tf inside the modules/ec2 directory:

nano modules/ec2/main.tf

Add the following code to the file:

variable "instance_type" {
  description = "The type of EC2 instance to launch."
  default     = "t2.micro"
}

variable "ami_id" {
  description = "The AMI to use for the EC2 instance."
  default     = "ami-0c55b159cbfafe1f0" # Amazon Linux 2 AMI
}

variable "security_group_id" {
  description = "The ID of the security group to associate with the EC2 instance."
}

variable "user_data" {
  description = "The user data script to run on instance launch."
}

resource "aws_instance" "web_server" {
  ami           = var.ami_id
  instance_type = var.instance_type
  security_groups = [var.security_group_id]
  user_data     = var.user_data

  tags = {
    Name = "My-Web-Server"
  }
}

output "public_ip" {
  value = aws_instance.web_server.public_ip
}

Step 3: Create the UserData Script

This script will be executed when the EC2 instance starts. It will update the system, install Apache, and create a simple index.html file.

Create a file named apache_userdata.sh in the root of your project directory:

nano apache_userdata.sh

Add the following script to the file:

#!/bin/bash
sudo yum update -y
sudo yum install -y httpd
sudo systemctl start httpd
sudo systemctl enable httpd
echo "<h1>Hello World from $(hostname -f)</h1>" | sudo tee /var/www/html/index.html

Make the script executable:

chmod +x apache_userdata.sh

Step 4: Create the Main Terraform Configuration

This is the main file that will bring everything together. It will use the modules we created to deploy the infrastructure.

Create a file named main.tf in the root of your project directory:

nano main.tf

Add the following code to the file:

provider "aws" {
  region = "us-east-1" # Change to your preferred region
}

module "security_group" {
  source = "./modules/security_group"
}

module "ec2_instance" {
  source            = "./modules/ec2"
  security_group_id = module.security_group.security_group_id
  user_data         = file("apache_userdata.sh")
}

output "instance_public_ip" {
  value = module.ec2_instance.public_ip
}

Step 5: Deploy the Infrastructure

Now we are ready to deploy our infrastructure.

Initialize Terraform: This command will download the necessary provider plugins.
```
terraform init
```
Plan the Deployment: This command will show you what resources Terraform will create.
```
terraform plan
```
Apply the Changes: This command will create the resources in your AWS account.
```
terraform apply --auto-approve
```

Step 6: Verify the Deployment

Once the terraform apply command is complete, it will output the public IP address of your EC2 instance.

Copy the Public IP: Copy the instance_public_ip from the output.
Access the Web Server: Open your web browser and navigate to the public IP address. You should see the "Hello World" message from your Apache server.

http://<your-instance-public-ip>
SSH into the Instance (Optional): You can also SSH into the instance to verify that Apache is running.
```
ssh -i "your-key.pem" ec2-user@<your-instance-public-ip>
```
Check the status of the httpd service:
```
sudo systemctl status httpd
```

🧹 Clean Up

To avoid incurring unnecessary costs, it's important to destroy the resources you've created.

Run the following command to destroy all the resources managed by this Terraform configuration:

terraform destroy --auto-approve

🐞 Troubleshooting

Problem	Cause	Solution
Connection Timed Out when accessing the web server	Security group is not configured correctly.	Double-check your security group module to ensure that inbound traffic on port 80 is allowed from `0.0.0.0/0`.
Terraform complains about missing provider	You haven't run `terraform init`.	Run `terraform init` in your project's root directory to download the necessary provider plugins.
EC2 instance doesn't have a public IP	The subnet you are deploying to does not assign public IPs.	Ensure that the "Auto-assign public IPv4 address" setting is enabled for the subnet you are deploying to. You can also explicitly associate an Elastic IP.
Apache is not running	There was an error in the `UserData` script.	SSH into the instance and check the cloud-init logs at `/var/log/cloud-init-output.log` for any errors.

💡 Further Exploration

Here are some ideas to expand on this project:

Use Variables: Make your modules more flexible by using variables for things like the instance type, AMI, and security group rules.
Add a Load Balancer: Create another module for an Application Load Balancer to distribute traffic to multiple EC2 instances.
More Complex UserData: Deploy a more complex application, such as a Node.js or Python web application.
Remote State: Configure Terraform to store its state file in an S3 bucket for better collaboration and state management.

📜 Conclusion

Congratulations! You have successfully created a modular Terraform project to deploy an EC2 instance with a web server. This project has taught you the fundamentals of Terraform modules, which are essential for building scalable and maintainable infrastructure as code.

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Terraform EC2 and Security Group Modules with Apache2

📦 Introduction

🎯 Project Goals

🛠️ Prerequisites

📂 Project Structure

1. Create the Project Directory

2. Create the Module Directories

🚀 Step-by-Step Guide

Step 1: Create the Security Group Module

Step 2: Create the EC2 Instance Module

Step 3: Create the UserData Script

Step 4: Create the Main Terraform Configuration

Step 5: Deploy the Infrastructure

Step 6: Verify the Deployment

🧹 Clean Up

🐞 Troubleshooting

💡 Further Exploration

📜 Conclusion

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Terraform EC2 and Security Group Modules with Apache2

📦 Introduction

🎯 Project Goals

🛠️ Prerequisites

📂 Project Structure

1. Create the Project Directory

2. Create the Module Directories

🚀 Step-by-Step Guide

Step 1: Create the Security Group Module

Step 2: Create the EC2 Instance Module

Step 3: Create the UserData Script

Step 4: Create the Main Terraform Configuration

Step 5: Deploy the Infrastructure

Step 6: Verify the Deployment

🧹 Clean Up

🐞 Troubleshooting

💡 Further Exploration

📜 Conclusion