NAMENODE is reference for hdfs namenode. If it is single node HDFS configured it must be localhost. Also refer to core-site.xml file to check your exact path to HDFS.
deepak@deepak-HP-ProBook-650-G2:~$ cat /usr/local/hadoop/etc/hadoop/core-site.xml
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
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<!-- Put site-specific property overrides in this file. -->