def primary_machine_name
      # If it is a single machine environment, then return the name
      return machine_names.first if machine_names.length == 1

      # If it is a multi-machine environment, then return the primary
      @config.vm.defined_vms.each do |name, subvm|
        return name if subvm.options[:primary]
      end

      # If no primary was specified, nil it is
      nil
    end
def primary_machine_name
      # If it is a single machine environment, then return the name
      return machine_names.first if machine_names.length == 1

      # If it is a multi-machine environment, then return the primary
      @config.vm.defined_vms.each do |name, subvm|
        return name if subvm.options[:primary]
      end

      # If no primary was specified, nil it is
      nil
    end
Returns the name of the machine that is designated as the
 "primary."

 In the case of a single-machine environment, this is just the
 single machine name. In the case of a multi-machine environment,
 then this is the machine that is marked as primary, or nil if
 no primary machine was specified.

 @return [Symbol]