void putData(Path path, String data) {
        putData(path, Utf8.toBytes(data));
    }
Retrieves a node relative to the node of the active application

@param path a path relative to the currently active application
@return a Reader that can be used to get the data
configserver/src/main/java/com/yahoo/vespa/config/server/zookeeper/ZKApplication.java