What is yarn-remote-client used for? they are useless?

[lenguyenhaohiep]

There are 2 files (core-site.xml and yarn-site.xml) added into spark home folder. Do we use them for which purpose? I don't see they are used?

Actually, HDFS and Yarn are configured by using core-site.xml and yarn-site.xml inside HADOOP_CONF_DIR. Right?
Thanks