https://medium.com/p/b7c216292b5f

packer.json

{
  "variables": {
      "aws_access_key": "",
      "aws_secret_key": ""
  },
  "builders": [{
      "type": "amazon-ebs",
      "access_key": "{{user `aws_access_key`}}",
      "secret_key": "{{user `aws_secret_key`}}",
      "region": "us-east-1",
      "source_ami": "ami-4fc1c025",
      "instance_type": "t2.small",
      "ssh_username": "ubuntu",
      "ami_name": "coolapp {{timestamp}}",
      "iam_instance_profile": "your_instance_iam_profile",
      "run_tags": {"Name": "coolapp"},
      "run_volume_tags": {"Name": "coolapp"},
      "tags": {"Name": "coolapp"}

  }],
  "provisioners": [
      {
          "type": "shell",
          "inline": ["sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 6125E2A8C77F2818FB7BD15B93C4A3FD7BB9C367",
                     "sudo bash -c \"echo 'deb http://ppa.launchpad.net/ansible/ansible/ubuntu vivid main' > /etc/apt/sources.list.d/ansible.list\"",
                     "sudo apt-get update",
                     "sudo apt-get -y install ansible"]
      },
      {
          "type": "ansible-local",
          "playbook_file": "{{ template_dir }}/playbook.yml",
      }
  ]
}