Troubleshooting Hadoop

During the installation process, you might encounter issues related to configuration values, ports, and connectivity problems. Even though it is not possible to provide solutions for each and every potential issue that you might encounter, the following hints will be helpful to troubleshoot effectively and efficiently:

1. Check the following environment variable values for different logs:

   MAHOUT_LOG_DIR
   MAHOUT_LOGFILE
   

2. Check the log files at the following location for Hadoop application specific issues:

   [Hadoop installation directory]/logs/user logs
   

3. Make sure that hostnames are specified correctly across all the nodes in the cluster:

   Check the /etc/hosts file for correct IP/ host name mapping in all nodes
   

4. Check port numbers for accuracy in the configuration files, and check whether you have given hostname:port correctly in all the relevant configuration files.