Terraform Tutorial

Terraform User_Data

user_data

The user_data only runs at instance launch time.

Here is a sample of using user_data embedded into tf file:

resource "aws_instance" "user_data_example" {   ami           = lookup(var.ami_id, var.region)   instance_type = var.instance_type #  subnet_id     = aws_subnet.public_1.id   # Security group assign to instance   vpc_security_group_ids = [aws_security_group.allow_ssh.id]   # key name   key_name = var.key_name   user_data = <<EOF #! /bin/bash                 sudo yum update -y sudo yum install -y httpd.x86_64 sudo service httpd start sudo service httpd enable echo "<h1>Welcome to Httpd Server</h1>" | sudo tee /var/www/html/index.html EOF   tags = {     Name = "Ec2-User-data"   } }

 But we prefer to use a file() function:

resource "aws_instance" "user_data_example_input_file" {   ami           = lookup(var.ami_id, var.region)   instance_type = var.instance_type #  subnet_id     = aws_subnet.public_1.id   # Security group assign to instance   vpc_security_group_ids = [aws_security_group.allow_ssh.id]   # key name   key_name = var.key_name   user_data = "${file("apache_config.sh")}"   tags = {     Name = "Ec2-User-data-with-file"   } }

The apache_config.sh looks like this:

#! /bin/bash sudo yum update -y sudo yum install -y httpd.x86_64 sudo yum service httpd start sudo yum service httpd enable echo "<h1>Welcome to Httpd Server</h1>" | yum tee /var/www/html/index.html

Run Terraform Apply and see the Public IP in browser to see the above message