code: function(callback) { // # 1
  
            var startReplicas = Math.pow(Number(self.conf.balancing['REPLICA_BASE_NUMBER']), Number(self.conf.balancing['MAX_LEVEL']));
  
            var address = '';
            if (self.conf.zookeeper) {
              if (typeof self.conf.zookeeper === 'string' || self.conf.zookeeper instanceof String) {
                address = self.conf.zookeeper;
              } else {
                if (self.conf.zookeeper.address) address = self.conf.zookeeper.address;
              }
            }
  
            self.nodeManager = new NodeManager(
              address,
              false,
              function(err, message) {
                if (!err) {
                  console.info(' (init) ZOOKEEPER is connected');
                  self.nodeManager.addServerNode(self.conf, startReplicas, function(err, path, replicas) {
  
                    //if (!err) console.info('        ZOOKEEPER /' + self.conf.host + ':' + self.conf.port);
  
                    var serverName = path.substring(path.lastIndexOf('/') + 1, path.length);
                    self.serverNodePath = path;
  
                    self.serverName = serverName.split('^')[0];
  
                    if (replicas) {
                      self.replicas = replicas;
                    } else {
                      self.replicas = startReplicas;
                    }
  
                    // init balacing config
                    self.nodeManager.getConfigInfo('balancing', function(data) {
                      if (data) {
  
                        self.conf.balancing = data;
                        var configReplica = Math.pow(Number(self.conf.balancing['REPLICA_BASE_NUMBER']), Number(self.conf.balancing['MAX_LEVEL']));
  
                        if (self.replicas != configReplica) {
                          self._changeReplicas(configReplica);
                        }
                      }
                    });
  
                    callback(err);
                  });
                } else {
                  callback(err, message);
                }
              }
            );
          }
docs: ASYNC ARRAY (START)