core-site.xml

Add the following lines:
<property>
  <name>hadoop.tmp.dir</name>
  <value>/hadoop</value>
  <description>A base for other temporary directories.</description>
</property>

<property>
  <name>fs.default.name</name>
  <value>hdfs://localhost:54310</value>
  <description>The name of the default file system.  A URI whose
  scheme and authority determine the FileSystem implementation.  The
  uri's scheme determines the config property (fs.SCHEME.impl) naming
  the FileSystem implementation class.  The uri's authority is used
  to determine the host, port, etc. for a filesystem.</description>
</property>

Assigns data directory to /hadoop 

Use localhost for our hdfs server