windows_reboot_plugin.rb

# Quick hack to be able to reboot a Vagrant Windows VM during provisioning.
#
# This files goes in the same folder as your vagrant file.
#
# Then you (in your Vagrantfile):
#     require_plugin './windows_reboot_plugin'
# 
# Your provisioners run in order, so...
#    config.vm.provision :shell, :inline => "stuff that need a reboot"
#    config.vm.provision :reboot
#    config.vm.provision :shell, :inline => "stuff that need to run after a reboot"
#
# The provisioner takes care of remounting the shared folders.
#
# It has been tested on Windows Server 2012 with chef-solo provisioner running after
# reboot.
#
# This will work for the VirtualBox provider, for other providers, a 'remap_shared_folders'
# action must be added to the provider implementation.

require 'vagrant'

# Monkey patch VirtualBox provider to be able to remap shared folders after reboot.
module VagrantPlugins
  module ProviderVirtualBox
    module Action
      class MountSharedFolders < ShareFolders
        def initialize(app,env)
          super(app, env)
        end

        def call(env)
          @env = env
          @app.call(env)
          mount_shared_folders
        end
      end
      def self.action_remap_shared_folders
        Vagrant::Action::Builder.new.tap do |b|
          b.use MountSharedFolders
        end
      end
    end
  end
end

class WindowsRebootPlugin < Vagrant.plugin("2")
  name "Windows Reboot Plugin"
  provisioner "reboot" do

    class RebootProvisioner < Vagrant.plugin("2", :provisioner)
      def initialize(machine, config)
        super
      end
      def configure(root_config)
      end
      def provision
        @machine.communicate.execute("Restart-Computer -Force")
        begin 
          sleep 10
        end until @machine.communicate.ready?
        @machine.action('remap_shared_folders')
      end
      def cleanup
      end
    end
    RebootProvisioner
  end
end

SharedFolder's doesn't seem to be available on Vagrant 1.4+ see https://gist.github.com/scraplesh/7767407

ERROR root: Failed to load plugin: ./windows_reboot_plugin
ERROR root:  -- Error: #<NameError: uninitialized constant VagrantPlugins::ProviderVirtualBox::Action::SharedFolders>

Do you have an idea how this could be fixed?

They renamed SharedFolders to synced folders I believe. This code probably needs updated in light of that.