{
   "variables": {
       "project_id": null,
       "source_image": null,
       "machine_type": null
   },
   "builders": [ {
       "type": "googlecompute",
       "project_id": "{{user `project_id`}}",
       "image_name": "reddit-base-3-{{timestamp}}",
       "source_image": "{{user `source_image`}}",
       "zone": "europe-west1-b",
       "ssh_username": "appuser",
       "machine_type": "{{user `machine_type`}}",
       "image_description": "Homework 7; example of 'Packer' tool to build an image for GCE instances",
       "disk_size": "15",
       "disk_type": "pd-standard",
       "address": "addressname",
       "tags": ["puma-server", "http-server", "https-server"]
       }
    ],
    "provisioners": [ {
        "type": "shell",
        "script": "scripts/install_ruby.sh"
      }, {
        "type": "shell",
        "script": "scripts/install_mongodb.sh",
        "execute_command": "sudo {{.Path}}"
       }
    ]
}


{
   "variables": {
       "project_id": null,
       "source_image": null,
       "machine_type": null
   },
   "builders": [ {
       "type": "googlecompute",
       "project_id": "{{user `project_id`}}",
       "image_name": "reddit-base-3-{{timestamp}}",
       "source_image": "{{user `source_image`}}",
       "zone": "europe-west1-b",
       "ssh_username": "appuser",
       "machine_type": "{{user `machine_type`}}",
       "image_description": "Homework 7; example of 'Packer' tool to build an image for GCE instances",
       "disk_size": "15",
       "disk_type": "pd-standard",
       "network": "default",
       "tags": ["puma-server", "http-server", "https-server"]
       }
    ],
    "provisioners": [ {
        "type": "shell",
        "script": "scripts/install_ruby.sh"
      }, {
        "type": "shell",
        "script": "scripts/install_mongodb.sh",
        "execute_command": "sudo {{.Path}}"
       }
    ]
}


Change field 'address' to 'network'
Change field 'address' to 'network'
