packer.json

{
  "variables": {
    "source_image_family": "var",
    "machine_type": "var",
    "region": "var",
    "zone": "var",
    "project_id": "var",
    "service_account_json": "var"
  },
  "builders": [
    {
      "type": "googlecompute",
      "project_id": "{{user `project_id`}}",
      "machine_type": "{{user `machine_type`}}",
      "source_image_family": "{{user `source_image_family`}}",
      "region": "{{user `region`}}",
      "zone": "{{user `zone`}}",
      "image_description": "Demo Ubuntu Machine Image",
      "image_name": "u16demo-{{timestamp}}",
      "disk_size": 16,
      "disk_type": "pd-ssd",
      "ssh_username": "root",
      "account_file": "{{ user `service_account_json`}}"
    }
  ],
  "provisioners": [
    {
      "type": "shell",
      "inline": [
        "sleep 10",
        "uname -a",
        "uptime"
      ]
    },
    {
      "type": "shell",
      "script": "init.sh",
      "execute_command": "echo 'packer' | sudo -S sh -c '{{ .Vars }} {{ .Path }}'"
    }
  ]
}