terraform-course/demo-18/instance.tf

data "aws_ami" "ubuntu" {
  most_recent = true

  filter {
    name   = "name"
    values = ["ubuntu/images/hvm-ssd/ubuntu-trusty-14.04-amd64-server-*"]
  }

  filter {
    name   = "virtualization-type"
    values = ["hvm"]
  }

  owners = ["099720109477"] # Canonical
}

resource "aws_instance" "example" {
  ami           = "${data.aws_ami.ubuntu.id}"
  instance_type = "t2.micro"

  # the VPC subnet
  subnet_id = "${var.ENV == "prod" ? module.vpc-prod.public_subnets[0] : module.vpc-dev.public_subnets[0] }"

  # the security group
  vpc_security_group_ids = ["${var.ENV == "prod" ? aws_security_group.allow-ssh-prod.id : aws_security_group.allow-ssh-dev.id }"]

  # the public SSH key
  key_name = "${aws_key_pair.mykeypair.key_name}"
}