ubuntu packer image with docker installed

bloggy-docker.json

{
  "variables": {
    "vm_name": "bloggy-docker"
  },
  "builders": [
    {
      "type": "virtualbox-ovf",
      "headless": true,
      "source_path": "vms/bloggy-base.ovf",
      "ssh_username": "bloggard",
      "ssh_password": "<ha-ha,right>",
      "ssh_port": 22,
      "ssh_wait_timeout": "10000s",
      "shutdown_command": "echo 'bloggard'|sudo -S shutdown -P now",
      "guest_additions_path": "VBoxGuestAdditions_{{.Version}}.iso",
      "virtualbox_version_file": ".vbox_version",
      "vm_name": "{{ user `vm_name` }}",
      "output_directory": "image/",
      "vboxmanage": [
        [
          "modifyvm",
          "{{.Name}}",
          "--memory",
          "2048"
        ],
        [
          "modifyvm",
          "{{.Name}}",
          "--cpus",
          "2"
        ]
      ]
    }
  ],
  "provisioners": [
    {
      "type": "ansible-local",
      "playbook_file": "ansible/main.yml"
    }
  ]
}