terraform-userdata-lab/ ├── main.tf ├── variables.tf ├── terraform.tfvars ├── providers.tf ├── versions.tf ├── outputs.tf └── user_data.sh.tpl terraform-userdata-lab/ ├── main.tf ├── variables.tf ├── terraform.tfvars ├── providers.tf ├── versions.tf ├── outputs.tf └── user_data.sh.tpl terraform-userdata-lab/ ├── main.tf ├── variables.tf ├── terraform.tfvars ├── providers.tf ├── versions.tf ├── outputs.tf └── user_data.sh.tpl terraform { required_version = ">= 1.5.0" required_providers { aws = { source = "hashicorp/aws" version = "~> 5.0" } } } terraform { required_version = ">= 1.5.0" required_providers { aws = { source = "hashicorp/aws" version = "~> 5.0" } } } terraform { required_version = ">= 1.5.0" required_providers { aws = { source = "hashicorp/aws" version = "~> 5.0" } } } provider "aws" { region = var.aws_region } provider "aws" { region = var.aws_region } provider "aws" { region = var.aws_region } variable "aws_region" { type = string description = "AWS region" } variable "instance_type" { type = string description = "EC2 type" } variable "instance_name" { type = string description = "Name of instance" } variable "web_message" { type = string description = "Message shown on web page" } variable "common_tags" { type = map(string) description = "Common tags" } variable "aws_region" { type = string description = "AWS region" } variable "instance_type" { type = string description = "EC2 type" } variable "instance_name" { type = string description = "Name of instance" } variable "web_message" { type = string description = "Message shown on web page" } variable "common_tags" { type = map(string) description = "Common tags" } variable "aws_region" { type = string description = "AWS region" } variable "instance_type" { type = string description = "EC2 type" } variable "instance_name" { type = string description = "Name of instance" } variable "web_message" { type = string description = "Message shown on web page" } variable "common_tags" { type = map(string) description = "Common tags" } aws_region = "us-east-2" instance_type = "t2.micro" instance_name = "userdata-lab" web_message = "Hello from Terraform User Data!" common_tags = { Project = "UserDataLab" Owner = "Student" } aws_region = "us-east-2" instance_type = "t2.micro" instance_name = "userdata-lab" web_message = "Hello from Terraform User Data!" common_tags = { Project = "UserDataLab" Owner = "Student" } aws_region = "us-east-2" instance_type = "t2.micro" instance_name = "userdata-lab" web_message = "Hello from Terraform User Data!" common_tags = { Project = "UserDataLab" Owner = "Student" } #!/bin/bash yum update -y yum install -y nginx systemctl start nginx systemctl enable nginx echo "${web_message}" > /usr/share/nginx/html/index.html #!/bin/bash yum update -y yum install -y nginx systemctl start nginx systemctl enable nginx echo "${web_message}" > /usr/share/nginx/html/index.html #!/bin/bash yum update -y yum install -y nginx systemctl start nginx systemctl enable nginx echo "${web_message}" > /usr/share/nginx/html/index.html data "aws_ami" "amazon_linux" { most_recent = true owners = ["amazon"] filter { name = "name" values = ["al2023-ami-*-x86_64"] } } resource "aws_security_group" "web_sg" { name = "${var.instance_name}-sg" description = "Allow HTTP" ingress { from_port = 80 to_port = 80 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 = var.common_tags } resource "aws_instance" "web" { ami = data.aws_ami.amazon_linux.id instance_type = var.instance_type vpc_security_group_ids = [aws_security_group.web_sg.id] user_data = templatefile("${path.module}/user_data.sh.tpl", { web_message = var.web_message }) tags = merge(var.common_tags, { Name = var.instance_name }) } data "aws_ami" "amazon_linux" { most_recent = true owners = ["amazon"] filter { name = "name" values = ["al2023-ami-*-x86_64"] } } resource "aws_security_group" "web_sg" { name = "${var.instance_name}-sg" description = "Allow HTTP" ingress { from_port = 80 to_port = 80 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 = var.common_tags } resource "aws_instance" "web" { ami = data.aws_ami.amazon_linux.id instance_type = var.instance_type vpc_security_group_ids = [aws_security_group.web_sg.id] user_data = templatefile("${path.module}/user_data.sh.tpl", { web_message = var.web_message }) tags = merge(var.common_tags, { Name = var.instance_name }) } data "aws_ami" "amazon_linux" { most_recent = true owners = ["amazon"] filter { name = "name" values = ["al2023-ami-*-x86_64"] } } resource "aws_security_group" "web_sg" { name = "${var.instance_name}-sg" description = "Allow HTTP" ingress { from_port = 80 to_port = 80 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 = var.common_tags } resource "aws_instance" "web" { ami = data.aws_ami.amazon_linux.id instance_type = var.instance_type vpc_security_group_ids = [aws_security_group.web_sg.id] user_data = templatefile("${path.module}/user_data.sh.tpl", { web_message = var.web_message }) tags = merge(var.common_tags, { Name = var.instance_name }) } output "public_ip" { value = aws_instance.web.public_ip } output "url" { value = "http://${aws_instance.web.public_ip}" } output "public_ip" { value = aws_instance.web.public_ip } output "url" { value = "http://${aws_instance.web.public_ip}" } output "public_ip" { value = aws_instance.web.public_ip } output "url" { value = "http://${aws_instance.web.public_ip}" } terraform init terraform init terraform init terraform apply terraform apply terraform apply terraform output url terraform output url terraform output url Hello from Terraform User Data! Hello from Terraform User Data! Hello from Terraform User Data! terraform taint aws_instance.web terraform apply terraform taint aws_instance.web terraform apply terraform taint aws_instance.web terraform apply user_data_replace_on_change = true user_data_replace_on_change = true user_data_replace_on_change = true user_data_replace_on_change = true user_data_replace_on_change = true user_data_replace_on_change = true - Installs Nginx automatically - Starts the service - Serves a custom web page - Automatically when EC2 starts - Only on first boot (by default) - Install packages (nginx, docker) - Configure apps - Pull code from Git - Start services - Any change in user_data → instance recreated