terraform ansible provisioning hack uses environment variables:DEBIAN_FRONTEND=noninteractive, AWS_PRIV_KEY=one line using \n, ANSIBLE_HOST_KEY_CHECKING=false, AWS_ACCESS_KEY_ID, and AWS_SECRET_ACCESS_KEY

ansible-hacks.tf

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

resource "aws_instance" "terraform-test" {
  ami = "ami-408c7f28"
  instance_type = "t1.micro"
  key_name = "atlas-testing"
  security_groups = ["terraform-testing"]
}

resource "null_resource" "Provision" {
  provisioner "local-exec" {
    command = <<EOF
    sudo apt-get -y update
    sudo apt-get -y install python-dev python-pip
    sudo pip install ansible
    echo $AWS_PRIV_KEY > priv.key
    chmod 400 priv.key
    ansible-playbook --private-key=priv.key -u ubuntu -i ${aws_instance.terraform-test.public_ip}, ansible/deploy.yml
EOF
  }
}

nice!