🎯 Lab Goal

You will:

• Create an EC2 instance
• Install NGINX using remote-exec
• Save EC2 IP locally using local-exec
• Upload a file using file provisioner
• Verify everything in browser

🧱 STEP 1 — Prerequisites (VERY IMPORTANT)

✅ You must have:

• AWS account
• Terraform installed

• Key pair created in AWS:

  • Name: terraform-key
  • Download: terraform-key.pem

✅ Place file in your project:

provisioner-lab/
  main.tf
  terraform-key.pem
  index.html

🧱 STEP 2 — Fix Key Permissions (Mac/Linux)

chmod 400 terraform-key.pem

❗ If you skip → SSH WILL FAIL

🧱 STEP 3 — Create index.html (file provisioner test)

📄 index.html

<h1>Welcome from Terraform Provisioner Lab</h1>

🧱 STEP 4 — Security Group (AWS Console)

Allow:

Copy Security Group ID:

sg-xxxxxxxx

🧱 STEP 5 — Full Terraform Code

📄 main.tf

provider "aws" {
  region = "us-east-1"
}

resource "aws_instance" "web" {
  ami           = "ami-0c02fb55956c7d316" # Amazon Linux 2
  instance_type = "t2.micro"

  key_name = "terraform-key"

  vpc_security_group_ids = ["sg-xxxxxxxx"] # replace

  # ✅ FILE PROVISIONER (upload HTML)
  provisioner "file" {
    source      = "index.html"
    destination = "/home/ec2-user/index.html"

    connection {
      type        = "ssh"
      user        = "ec2-user"
      private_key = file("terraform-key.pem")
      host        = self.public_ip
    }
  }

  # ✅ REMOTE-EXEC (install nginx + deploy page)
  provisioner "remote-exec" {
    inline = [
      "sudo yum install nginx -y",
      "sudo systemctl start nginx",
      "sudo systemctl enable nginx",
      "sudo mv /home/ec2-user/index.html /usr/share/nginx/html/index.html"
    ]

    connection {
      type        = "ssh"
      user        = "ec2-user"
      private_key = file("terraform-key.pem")
      host        = self.public_ip
    }
  }

  # ✅ LOCAL-EXEC (save IP locally)
  provisioner "local-exec" {
    command = "echo ${self.public_ip} > public_ip.txt"
  }

  tags = {
    Name = "provisioner-lab"
  }
}

🧪 STEP 6 — Run Terraform

terraform init
terraform apply -auto-approve

⚙️ WHAT HAPPENS INTERNALLY

1. EC2 instance created
2. Terraform connects via SSH
3. File provisioner uploads HTML
4. Remote-exec installs nginx
5. HTML moved to nginx folder
6. local-exec saves IP to file

🔍 STEP 7 — VERIFY

✅ Check local file

cat public_ip.txt

Example:

3.145.23.10

✅ Open browser

http://<EC2_PUBLIC_IP>

👉 You should see:

Welcome from Terraform Provisioner Lab

🧪 STEP 8 — TEST & BREAK (IMPORTANT FOR INTERVIEW)

❌ Test 1: Wrong key

Change:

private_key = file("wrong.pem")

👉 Result:

• SSH fails
• Provisioning fails

❌ Test 2: Remove port 22

👉 Result:

• Terraform hangs (waiting SSH)

❌ Test 3: Remove sudo

👉 Result:

• Permission denied
• NGINX not installed

🔁 STEP 9 — DESTROY

terraform destroy -auto-approve

🧠 WHAT YOU LEARNED

Provisioners:

• file → copy file
• remote-exec → configure server
• local-exec → run locally

Execution order:

1. Create EC2
2. file provisioner
3. remote-exec
4. local-exec

Key concepts:

• self.public_ip
• SSH connection block
• Key permissions
• Provisioner dependency on resource

🎯 REAL DEVOPS TIP (IMPORTANT)

👉 In production, replace this with:

• user_data (bootstrap)
• Ansible (config)
• Packer (pre-built AMI)