Troubleshooting

Describes changes to core-site.xml file to troubleshoot issues.

fs.mapr.bind.retries Parameter

If there are issues when binding because of unavailability of port, set the value for fs.mapr.bind.retries configuration parameter in core-site.xml file to true. If true, the client will keep trying to bind during client initialization for 5 minutes before failing. By default, the fs.mapr.bind.retries configuration parameter is set to false.

For example, your entry in core-site.xml file should look similar to the following:

<property>
  <name>fs.mapr.bind.retries</name>
  <value>true</value>
  <description>Bind during client initialization for 5 minutes</description>
</property>

fs.mapr.bailout.on.library.mismatch Parameter

When running any application with older versions of the MapR JARs, the system could hang if the older JARs link to the native library installed on cluster nodes that have been updated to a newer MapR version. The fs.mapr.bailout.on.library.mismatch parameter detects mismatched libraries, fails the job, and logs an error message. The parameter is enabled by default. You can disable the parameter on all the YARN nodes and resubmit the job for the job to continue to run. To disable the parameter, you must set it to false in the core-site.xml file.

For example, to disable, your entry in the core-site.xml file should look similar to the following:

<property>
  <name>fs.mapr.bailout.on.library.mismatch</name>
  <value>false</value>
  <description>Disabling to continue running jobs</description>
</property>

libMapRClient.so Binary

The libMapRClient.so binary is in /opt/mapr/lib directory and also bundled in maprfs-XXX.jar file. All the applications that include the JAR will also have libMapRClient.so binary. If there are multiple libMapRClient.so on a machine and if you know the location of all the JARs, you can run the following commands to check the mapr version of a binary:

# jar tvf mapr-<XXX>.jar | grep libMapRClient.so
# jar xvf mapr-<XXX>.jar com/mapr/fs/native/Linux/x86_64/libMapRClient.so
# cd com/mapr/fs/native/Linux/x86_64/
# strings libMapRClient.so | grep mapr-version
# cd /opt/mapr/lib
# strings libMapRClient.so | grep mapr-version

This is useful in determining if there are old binaries installed on the system.