code: private void doConnect() {
          try {
              LOG.info("Connecting to zookeeper server - " + RpcClientConf.ZK_SERVER_LIST);
              zkClient = new SimpleZooKeeperClient(RpcClientConf.ZK_SERVER_LIST,
                      RpcClientConf.ZK_DIGEST_AUTH, new ServiceWatcher());
              updateServiceLocalCache();
          } catch (Exception e) {
              LOG.error("Zookeeper client initialization failed, " + e.getMessage(), e);
          }
      }
docs: Connect to zookeeper server