The files located on $OPENNMS_HOME/etc/examples/drools-engine.d/nodeParentRules/, to be more precise NodeParentRules.drl and drools-engine.xml are not properly initializing the logging engine which makes the rules unusable.
I was able to verify this behavior by just copy the files from the examples directory into opennms-correlation/drools-correlation-engine/src/test/opennms-home/etc/drools-engine.d/nodeParentRules/. The JUnit tests related with these files won't pass.
Actually, I think that the files we ship with OpenNMS must be identical to the files we verified through JUnit tests.
For the logging issue, we should at least comment the lines on the affected files for now, until we figure out how to properly initialize the logging engine with drools.