(1)core-site.xml:-This file have Hadoop core configuration settings like I/O settings, very common for MapReduce and HDFS. and it uses hostname a port.
(2)mapred-site.xml:-This file specifies a framework name for MapReduce by setting mapreduce.framework.name
(3)hdfs-site.xml:-This file contains HDFS daemons configuration settings. It also specifies default block permission and replication checking on HDFS.
(4)yarn-site.xml:-This files specifies configuration settings for ResourceManager and NodeManager.
