No debug or error logs appear to be being created for bundles using slf4j logging loaded into OpenNMS 21.0.0 running karaf 4.1.2 with the upgrade to log4j2.
This relates to changes to using log4j2 when upgrading to karaf 4.1.2
This may be related to ClassNotFoundException for org.apache.logging.log4j.core.util.ExecutorServices in output.log
(Note surprisingly bundles which log using jdk or jcl logging do appear to generate logs in karaf.log)
I have created a small test bundle (source and jar attached) which can be dropped into the deploy directory
This repeatedly outputs message to System.out, DEBUG,ERROR. The System.out messages show up in output.log but no other log messages are created.
Note that this bundle works as expected in OpenNMS versions prior to 21.0.0 and in stand alone karaf 4.1.2 installations.
I did think that there might be a class path issue with having log4j 2 in the lib directory. I have tried to add log4j2 classes to opennms custom.properties but so far this has not worked
So far I am left scratching my head and unable to get debug messages for karaf deployed bundles