anchor.diff:  
   -spec add_or_remove_vms(add | remove, integer()) ->  fail | ok.
   add_or_remove_vms(Flag, Pending) ->
  -	case get_hosts() of
  +    case get_hosts() of
       	{TLog, Hosts} ->
  -			UpdatedHosts = add_or_remove_vms(Flag, Pending, Hosts, []),
  -			save_hosts(TLog, UpdatedHosts);
  -		fail -> fail
  -	end.
  +            UpdatedHosts = add_or_remove_vms(Flag, Pending, Hosts, []),
  +            save_hosts(TLog, UpdatedHosts);
  +        fail -> fail
  +    end.
   
   -spec add_or_remove_vms(add | remove, integer(), hostlist(), hostlist()) -> hostlist().
   add_or_remove_vms(_Flag, _Pending = 0, Hosts, UpdatedHosts) ->
  
positive.code: 
  -spec killall_vms() -> fail | ok.
  killall_vms() ->
  	case get_hosts() of
  		{_, Hosts} ->
      		lists:foreach(fun({Hostname, Status}) ->
                                    case Status of
                                        active ->
                                            scalaris_vm(stop, Hostname);
  
negative.code:     Scalaris = get_scalaris_service(),
      Services = [Scalaris | get_additional_services()],
      lists:foreach(fun (Service) ->
                            {StartCmd, StopCmd} = Service,
                            ServiceCmd =
                                case Action of
                                    start -> StartCmd;
                                    stop  -> StopCmd
                                end,
                            Cmd = format("ssh -n -f ~s \"(~s)\"", [Hostname, ServiceCmd]),
                            ?TRACE("Executing: ~p~n", [Cmd]),
                            _ = exec(Cmd)
                    end, Services),
      ok.
  
  -spec format(string(), list()) -> string().
  format(FormatString, Items) ->
      lists:flatten(io_lib:format(FormatString, Items)).
  
  -spec get_hosts() -> fail | {tx_tlog:tlog_ext(), hostlist()}.
  get_hosts() ->
      case api_tx:read(api_tx:new_tlog(), ?cloud_ssh_key) of
          {TLog, {ok, Hosts}} -> {TLog, Hosts};
          _ -> fail
      end.
  
  -spec save_hosts(hostlist()) -> fail | ok.
  save_hosts(Hosts) ->
      save_hosts(api_tx:new_tlog(), Hosts).
  
  -spec save_hosts(tx_tlog:tlog_ext(), hostlist()) -> fail | ok.
  save_hosts(TLog, Hosts) ->
      case api_tx:req_list(TLog, [{write, ?cloud_ssh_key, Hosts}, {commit}]) of
          {[], [{ok}, {ok}]} -> ok;
          _ -> fail
      end.
  
  -spec get_scalaris_service() ->  tuple(string(), string()).
  get_scalaris_service() ->
  