12.5. Verifying the Configuration

Prior to submitting any jobs, ensure that the trusted storage pool is running. Launch the Ambari Dashboard (http://ambari-server-hostname:8080) and select the YARN service and then click the Start-All button.

The default volume (usually HadoopVol) must always be running when you are running Hadoop Jobs on other volumes. This is because the user directories for all the deployed Hadoop processes are stored on this volume. For example, if you have created and enabled 3 volumes for use with Hadoop (HadoopVol, MyVolume1, MyVolume2) and you are running a Hadoop Job thats reads from MyVolume 1 and writes to MyVolume 2, then HadoopVol must still be running.

To test your trusted storage pool, shell into the YARN Master server and navigate to the /usr/lib/hadoop/ directory. Then su to one of the users you have enabled for Hadoop (such as tom) and submit a Hadoop Job:

For more information on using specific components within the Hadoop Ecosystem, see Chapter 2. Understanding the Hadoop Ecosystem in the Hortonworks Data Platform documentation.