ある日何気なく最新版のvagrant-berkshelf(4.0.4)を入れたところ、 It appears that you are not using the ChefDK. Please note that Vagrant Berkshelf works best when used with the ChefDK, and other installation methods are not officially supported. Please download and install the latest version of the ChefDK from: https://downloads.getchef.com/chef-dk and follow the installation instructions. Do not forget to add the Chef