How to create a VirtualBox machine with encrypted storage with Vagrant (2.2.7)

Vagrantfile

# -*- mode: ruby -*-
# vi: set ft=ruby :

# Forked from https://gist.github.com/gabrielelana/9189eab5df963deba30f
# Works with Vagrant 2.2.7 (trigger)

# After the first `vagrant up` stop the VM and execute the following steps
# Take the identifier of the storage you want to encrypt
# > HDD_UUID=`VBoxManage showvminfo <VM_NAME> | grep 'SATA.*UUID' | sed 's/^.*UUID: \(.*\))/\1/'`
# Store your usernname (whitespaces are not allowed) in a variable
# > USERNAME="<YOUR_USER_NAME_WITHOUT_WHITESPACES>"
# Encrypt the storage, enter the password when asked
# > VBoxManage encryptmedium $HDD_UUID --newpassword - --newpasswordid $USERNAME --cipher "AES-XTS256-PLAIN64"
# Store the username in a file named .password_id
# > echo $USERNAME > .password_id
# Now, the next time you start the VM you'll be asked for the same password

# .password
PASSWORD_PATH = ".password" 
# .password_id
PASSWORD_ID_PATH = ".password_id"

# All Vagrant configuration is done below. The "2" in Vagrant.configure
# configures the configuration version (we support older styles for
# backwards compatibility). Please don't change it unless you know what
# you're doing.
Vagrant.configure("2") do |config|
  # The most common configuration options are documented and commented below.
  # For a complete reference, please see the online documentation at
  # https://docs.vagrantup.com.

  # Every Vagrant development environment requires a box. You can search for
  # boxes at https://vagrantcloud.com/search.
  config.vm.box = "archlinux/archlinux"

  # Disable automatic box update checking. If you disable this, then
  # boxes will only be checked for updates when the user runs
  # `vagrant box outdated`. This is not recommended.
  # config.vm.box_check_update = false

  # Create a forwarded port mapping which allows access to a specific port
  # within the machine from a port on the host machine. In the example below,
  # accessing "localhost:8080" will access port 80 on the guest machine.
  # NOTE: This will enable public access to the opened port
  # config.vm.network "forwarded_port", guest: 80, host: 8080

  # Create a forwarded port mapping which allows access to a specific port
  # within the machine from a port on the host machine and only allow access
  # via 127.0.0.1 to disable public access
  # config.vm.network "forwarded_port", guest: 80, host: 8080, host_ip: "127.0.0.1"

  # Create a private network, which allows host-only access to the machine
  # using a specific IP.
  # config.vm.network "private_network", ip: "192.168.33.10"

  # Create a public network, which generally matched to bridged network.
  # Bridged networks make the machine appear as another physical device on
  # your network.
  # config.vm.network "public_network"

  # Share an additional folder to the guest VM. The first argument is
  # the path on the host to the actual folder. The second argument is
  # the path on the guest to mount the folder. And the optional third
  # argument is a set of non-required options.
  # config.vm.synced_folder "../data", "/vagrant_data"

  # Provider-specific configuration so you can fine-tune various
  # backing providers for Vagrant. These expose provider-specific options.
  # Example for VirtualBox:
  #
  # config.vm.provider "virtualbox" do |vb|
  #   # Display the VirtualBox GUI when booting the machine
  #   vb.gui = true
  #
  #   # Customize the amount of memory on the VM:
  #   vb.memory = "1024"
  # end
  #
  # View the documentation for the provider you are using for more
  # information on available options.

  # Enable provisioning with a shell script. Additional provisioners such as
  # Ansible, Chef, Docker, Puppet and Salt are also available. Please see the
  # documentation for more information about their specific syntax and use.
  # config.vm.provision "shell", inline: <<-SHELL
  #   apt-get update
  #   apt-get install -y apache2
  # SHELL

  config.trigger.before :up do |trigger|
    trigger.info = "Log: Running before up trigger..."
    trigger.ruby do |env,machine|
      if File.exists?(PASSWORD_ID_PATH)
        unless File.exists?(PASSWORD_PATH)
          password_id = File.read(PASSWORD_ID_PATH).strip
          print "The VM is encrypted, please enter the password\n#{password_id}: "
          password = STDIN.noecho(&:gets).strip
          File.write(PASSWORD_PATH, password)
          puts ""
        end
      end
    end
  end

  config.trigger.after :up do |trigger|
    trigger.info = "Log: Running after up trigger..."
    trigger.ruby do |env,machine|
      File.delete(PASSWORD_PATH) if File.exists?(PASSWORD_PATH)
    end
  end

  config.trigger.after :destroy do |trigger|
    trigger.info = "Log: Running after destroy trigger..."
    trigger.ruby do |env,machine|
      File.delete(PASSWORD_ID_PATH) if File.exists?(PASSWORD_ID_PATH)
    end
  end

  config.vm.provider :virtualbox do |vb|
    # vb.name = "secure"
    vb.gui = false

    if File.exists?(PASSWORD_ID_PATH)
      password_id = File.read(PASSWORD_ID_PATH).strip
      vb.customize "post-boot", ["controlvm", :id, "addencpassword", password_id, PASSWORD_PATH, "--removeonsuspend", "yes"]
    end
  end
end

So yes, indeed, I think that the only way to do so is to pass a variable to Vagrantfile.

if ENCRYPTION.eql?("--encryption")) print "Please enter the VM's passphrase : " password = STDIN.noecho(&:gets).strip File.write(PASSWORD_PATH, password) puts "" end

if ENCRYPTION.eql?("--encryption")
  vb.customize "post-boot",  [ "controlvm", :id, "addencpassword", vb.name, PASSWORD_PATH, "--removeonsuspend", "yes"] 
end

so basically when you do something like
vagrant --encryption reload

It will prompt you for password, then Vagrant will call VB's decryption API.

And if you do just vagrant up then it won't.

I hope this can help someone that needs to implement encryption mechanism without having to define one .password_id file.

David