Terraform EC2 Provisioning

The Complete Terraform Code

Save this code in a file named main.tf. This single file defines the provider, your SSH keys, the networking firewall rules, and the final EC2 compute instance.

provider "aws" {
  region = "ap-south-1"
}

# Create Key Pair
resource "aws_key_pair" "my_key" {
  key_name   = "terraform-key"
  public_key = file("~/.ssh/id_rsa.pub")
}

# Create Security Group
resource "aws_security_group" "web_sg" {
  name        = "terraform-sg"
  description = "Allow SSH and HTTPS"

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

  ingress {
    description = "Allow HTTPS"
    from_port   = 443
    to_port     = 443
    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"]
  }

  tags = {
    Name = "terraform-sg"
  }
}

# Create EC2 Instance
resource "aws_instance" "web" {
  ami                    = "ami-xxxxxxxxxxxxxxxxx"
  instance_type          = "t2.micro"
  key_name               = aws_key_pair.my_key.key_name
  vpc_security_group_ids = [aws_security_group.web_sg.id]

  root_block_device {
    volume_size = 30
    volume_type = "gp3"
  }

  tags = {
    Name = "Terraform-EC2"
  }
}

Code Breakdown

Understanding the exact building blocks of this Terraform file guarantees you can modify it safely later.

Core Blocks

• Provider Configures Terraform to use AWS and sets the deployment region to ap-south-1 (Mumbai).
• Key Pair Reads your local public SSH key (~/.ssh/id_rsa.pub) and creates an AWS Key Pair, enabling secure remote login to the instance without passwords.
• Tags Applied to both the Security Group and the EC2 instance to help identify AWS resources easily in the AWS Billing and Web Console.

Security Group (Virtual Firewall)

• Inbound Rules: Opens Port 22 for SSH (Remote login) and Port 443 for HTTPS (Secure web traffic).
• Outbound Rules: The protocol = "-1" string allows all outbound traffic, letting the server connect to the internet to download updates.

The EC2 Instance

Creates the actual virtual machine. It links the Key Pair and Security Group IDs dynamically.

Root Block Device: Configures the underlying storage disk attached to the instance, overriding the default size to guarantee a 30 GB GP3 SSD.

Deployment & Execution

terminal

# 1. Initialize Terraform
# Downloads the AWS provider and initializes the directory
$ terraform init

# 2. Check the execution plan
# Displays the resources Terraform will create without making changes
$ terraform plan

# 3. Create the infrastructure
# Type 'yes' when prompted
$ terraform apply

# 4. Destroy the infrastructure (When done)
# Type 'yes' when prompted to delete all created resources
$ terraform destroy

Step 4: The Final Result

After running terraform apply, the following AWS resources are created successfully and linked together:

• ✓ AWS Provider configured in ap-south-1
• ✓ One Key Pair (terraform-key)
• ✓ One Security Group (terraform-sg) with SSH and HTTPS enabled
• ✓ One EC2 Instance (t2.micro)
• ✓ One 30 GB GP3 Root EBS Volume attached