template.json

{
 "provisioners": [
    {
      "type": "shell",
      "execute_command": "echo 'vagrant' | {{.Vars}} sudo -S -E bash '{{.Path}}'",
      "script": "scripts/setup.sh"
    },
    {
      "type": "shell",
      "execute_command": "echo 'vagrant' | {{.Vars}} sudo -S -E bash '{{.Path}}'",
      "script": "scripts/cleanup.sh"
    }
],
  "builders": [{
    "type": "virtualbox-iso",
    "boot_command": [
      "<enter><f6><esc>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs><bs><bs>",
      "<bs><bs><bs>",
      "auto preseed/url=http://{{.HTTPIP}}:{{.HTTPPort}}/http/xenial-preseed.cfg ",
      "debian-installer/allow_unauthenticated_ssl=true ",
      "debian-installer=en_US locale=en_US kbd-chooser/method=us ",
      "hostname=minimal-xenial ",
      "fb=false debconf/frontend=noninteractive ",
      "keyboard-configuration/modelcode=SKIP keyboard-configuration/layout=USA ",
      "keyboard-configuration/variant=USA console-setup/ask_detect=false ",
      "vga=788 initrd=/install/initrd.gz quiet --- ",
      "<enter>"
    ],
    "boot_wait": "4s",
    "guest_os_type": "Ubuntu_64",
    "http_directory": "./",
    "iso_checksum": "d2d939ca0e65816790375f6826e4032f",
    "iso_checksum_type": "md5",
    "iso_url": "http://releases.ubuntu.com/16.04.1/ubuntu-16.04.1-server-amd64.iso",
    "ssh_username": "vagrant",
    "ssh_password": "vagrant",
    "keep_registered": "true",
    "ssh_wait_timeout": "10000s",
    "disk_size": "60000",
    "shutdown_command": "echo 'vagrant' | sudo -S shutdown -P now",
    "shutdown_timeout": "7m",
    "vboxmanage": [
      [ "modifyvm", "{{.Name}}", "--memory", "1024" ],
      [ "modifyvm", "{{.Name}}", "--cpus", "1" ],
      [ "modifyvm", "{{.Name}}", "--audio", "none" ],
      [ "modifyvm", "{{.Name}}", "--usb", "off" ]
    ]
  }],
  "post-processors": [
    {
        "type": "vagrant",
        "compression_level": 9,
        "only": ["virtualbox-iso"],
        "output": "minimal-xenial64.box",
        "vagrantfile_template": "./Vagrantfile"
    }
  ]
}