Sample terraform config for blog post

main.tf

variable "region" { type = string }
variable "ssh_source_ips" { type = list(string) }  # list of CIDR blocks
variable "ami_owner_id" { type = string }
variable "key" { type = tuple([string, string]) }  # key_name and path to local private key

provider "aws" {
  profile    = "terraform"
  region     = var.region
}

data "aws_ami" "ubuntu_18" {
  most_recent = true
  owners = [var.ami_owner_id]

  filter {
    name   = "name"
    values = ["ubuntu/images/hvm-ssd/ubuntu-bionic-18.04-amd64-server-*"]
  }
}

resource "aws_instance" "my_vm" {
  ami           = data.aws_ami.ubuntu_18.id
  instance_type = "t2.micro"
  key_name        = var.key[0]
  security_groups = [aws_security_group.ssh_http.name]

  provisioner "remote-exec" {
    inline = [
      "sleep 10",
      "sudo apt-get update",
      "sudo apt-get -y install apache2",
    ]
    connection {
      type        = "ssh"
      user        = "ubuntu"
      private_key = file(var.key[1])
      host        = self.public_ip
    }
  }

}

resource "aws_security_group" "ssh_http" {
  name        = "ssh_http"
  description = "Allow SSH and HTTP"

  ingress {
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = var.ssh_source_ips
  }
  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"]
  }
}

output "instance_ip" {
  value = aws_instance.my_vm.public_ip
}

output "chosen_ami" {
  value = data.aws_ami.ubuntu_18.id
}

terraform.tfvars

ssh_source_ips = ["x.x.x.x/28", "x.x.x.x/32"]
ami_owner_id = "099720109477". # Canonical
key = ["terraform", "~/.ssh/terraform"]