ec2/deploy.centos64/root/ephemeral-hdfs/conf/core-site.xml

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>

<!-- Put site-specific property overrides in this file. -->

<configuration>

  <property>
    <name>hadoop.tmp.dir</name>
    <value>/mnt/ephemeral-hdfs</value>
  </property>

  <property>
    <name>fs.default.name</name>
    <value>hdfs://{{active_master}}:9000</value>
  </property>

  <property>
    <name>io.file.buffer.size</name>
    <value>65536</value>
  </property>

</configuration>