the hostname of the zookeeper instance . example : ` 127.0.0.1 ` concode_field_sep TestingServer server concode_elem_sep Logger log concode_elem_sep int DEFAULT_PORT concode_field_sep void stop concode_elem_sep String connectString
String function ( ) { return connectString ( ) . substring ( 0 , connectString ( ) . lastIndexOf ( ':' ) ) ; }