packer/command/test-fixtures/hcl2_upgrade/varfile-with-no-variables-block/input.json

{
  "builders": [
    {
      "type": "null",
      "communicator": "ssh",
      "ssh_host": "{{ user `ssh_host` }}", 
      "ssh_password": "{{ user `ssh_password` }}",
      "ssh_username": "{{ user `ssh_username` }}"
    }
  ],
  "provisioners": [
    {
        "pause_before": "20s",
        "type": "shell-local",
        "inline": [ "echo {{ user `version_tag` }} > provision.txt" ]
    }
  ]
}