packer/vars/ubuntu-16.04.json

{
  "source_ami_filter_name": "*ubuntu*16.04*",
  "source_ami_filter_owner": "099720109477",

  "ssh_user": "ubuntu",

  "distro": "Ubuntu 16.04",
  "arch": "x86_64",
  "cloud_user_data": "provision/null_data.sh"
}