We can enhance the default flat rack configuration by creating a script that derives the rack location for each host.
Create a script in the Hadoop user's home directory on the NameNode host called
rack-script.sh, containing the following text. Remember to change the IP address to one of your HDFS nodes.#!/bin/bash if [ $1 = "10.0.0.101" ]; then echo -n "/rack1 " else echo -n "/default-rack " fiMake this script executable.
$ chmod +x rack-script.shAdd the following property to
core-site.xmlon the NameNode host:<property> <name>topology.script.file.name</name> <value>/home/Hadoop/rack-script.sh</value> </property>
Restart HDFS.
$ start-dfs.shCheck the filesystem via
fsck.$ Hadoop fsck –rackThe output of the preceding command can be shown in the following screenshot:
