Deploy Nginx Automatically Using Terraform user_data

Introduction

In the previous Terraform lab, we created AWS infrastructure using Terraform.

Now we’ll move one step further into real-world DevOps automation by automatically installing and configuring Nginx during EC2 deployment using Terraform user_data.

This is one of the most important concepts in Infrastructure as Code (IaC) because modern cloud servers are usually configured automatically during provisioning.

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Goal

Build a Terraform lab that:

• Creates AWS infrastructure

• Automatically installs Nginx

• Automatically starts the web server

• Serves a custom web page

• Uses AWS Free Tier safely

• Demonstrates a real-world provisioning workflow

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What You Will Learn

• What Terraform user_data is

• How EC2 bootstrapping works

• Automatic package installation

• Automated server configuration

• How to deploy Nginx automatically

• How Infrastructure as Code works in real environments

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Architecture

Terraform will create the following:

Internet
└─ Internet Gateway
└─ Public Subnet
└─ EC2 Instance
└─ Automatic Nginx Installation
└─ Website Accessible from Browser

Add architecture diagram screenshot here

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Why This Lab Is Important

Until now, Terraform only created infrastructure.

After this lab:

• Server configures itself automatically

• Nginx installs automatically

• Website becomes live automatically

• No manual package installation needed

This is how modern cloud automation works.

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Understanding user_data

AWS EC2 instances support something called user_data.

user_data allows us to run shell scripts automatically when the server starts for the first time. This can be used for:

• Installing software

• Creating users

• Updating packages

• Deploying applications

• Configuring services

This process is called bootstrapping.

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⚠️ AWS Free Tier Safety

Use ONLY:

• t2.micro or t3.micro

• One EC2 instance

• Small EBS volume

Avoid:

• NAT Gateway

• Load Balancers

• RDS

Always destroy resources after testing.

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Step 1 — Update Security Group

Previously we allowed only SSH access. Now also allow HTTP traffic on port 80.

Replace your ingress section with this:

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

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

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Step 2 — Update EC2 Resource

Replace your EC2 resource block with the following:

# -----------------------------
# EC2 Instance
# -----------------------------
resource "aws_instance" "ubuntu_server" {
  ami                         = "ami-03bb6d83c60fc5f7c"
  instance_type               = "t3.micro"
  subnet_id                   = aws_subnet.public_subnet.id
  vpc_security_group_ids      = [aws_security_group.lab_sg.id]
  associate_public_ip_address = true

  user_data = <<-EOF
              #!/bin/bash
              apt update -y
              apt install nginx -y

              systemctl enable nginx
              systemctl start nginx

              echo "<h1>Terraform Nginx Lab Working</h1>" > /var/www/html/index.html
              EOF

  tags = {
    Name = "terraform-nginx-server"
  }
}

Download the full main.tf file from here:
https://github.com/sanchitpandit/Devops/blob/main/terraform/tf-deploy-nginx/main.tf

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What This Script Does

When EC2 starts:

• Updates Ubuntu packages

• Installs Nginx

• Enables Nginx service

• Starts Nginx

• Creates a custom HTML page

Everything happens automatically.

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Step 3 — Format Terraform Files

Run:

terraform fmt

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Step 4 — View Terraform Plan

Run:

terraform plan

Terraform will detect infrastructure changes.

Step 5 — Apply Changes

Run:

terraform apply

Type:

yes

Terraform will update and create resources.

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Step 6 — Verify Nginx Installation

After deployment completes, open your browser:

http://PUBLIC-IP

Replace PUBLIC-IP with your EC2 public IP.

Expected Output

You should see the page with:

Terraform Nginx Lab Working

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Real-World DevOps Concepts Learned

This lab teaches:

• Bootstrapping

• Automated provisioning

• Immutable infrastructure

• Infrastructure automation

• Server initialization

• Cloud provisioning workflow

These are real production concepts used in DevOps environments.

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⚠️ Common Mistakes

• Forgetting to open port 80 — Browser will not load the website. Make sure Security Group allows port 80.

• Wrong AMI — Always use an Ubuntu AMI compatible with your region.

• Not waiting for user_data — Sometimes installation takes 1–2 minutes after EC2 starts. Wait briefly before testing the website.

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Real Business Usage

In production, user_data is used for:

• Web server deployment

• Monitoring agent installation

• Docker installation

• Kubernetes node preparation

• Security hardening

• Application deployment

This allows fully automated server provisioning.

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Cleanup

After testing, destroy all resources to avoid AWS charges.

Run:

terraform destroy

Type:

yes

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🎉 Conclusion

You have now moved beyond basic infrastructure deployment and entered real Infrastructure Automation using Terraform.

With user_data, your servers can:

• Configure themselves

• Install software automatically

• Become production-ready immediately after deployment

This is a core foundation of modern DevOps and Cloud Engineering.