When I run my Flink app via the Google Flink Operator, log4j2 logging doesn't show up in logs. System.out.println messages work.
Everything should be very plain-vanilla-standard setup. I have a log4j2.xml config file in my classpath included in my application .jar file. I'm building a custom Docker image based on `flink:1.14.3-scala_2.12-java11` that simply copies my application .jar and all transitive dependencies to `/opt/flink/lib`. My app is built with the same `org.apache.logging.log4j:log4j-core:2.17.1` dependency that Flink 1.14.3 uses. If I shell into my docker image and run `java -cp "/opt/flink/lib/*" myapp.LoggingTest`, the logging works, I see it on the console. When I submit this via the Google Flink Kubernetes Operator, I don't see the logging output, but I do see println output. If I change my app to use logback, I see that output, which is weird. How do I troubleshoot the log4j2 option? Or should I just use logback if that works? For a long running Flink job, I just want to see startup+config logs + exception logs. thank you :)
