Flink logs not showing up

Question

I have a Flink application deployed in the Dev cluster.

1. And I cannot see the logs anywhere in the Flink dashboard. I was told that they used the default logging level. And what might that be?

2. Where do I reset the logging levels, now that logs are not showing up for the default level?

3. Just to confirm, I added Sout statements exactly as I added logs. And they show up in the Task manager of the application in Kubernetes. So why not logs??

4. In the code, the logs are added as such :

   log.debug("log statement that you want to be displayed");

   Is that the final log level setting? Can I change the log level anywhere?

5. I mention point 4, because, log.debug() is equivalent to log.level().So if I am setting the level = debug here, then why do the log statements into showing up in Flink dashboard, when I run the app in the dev cluster?

Answer 1

I don't know where the logs go in Flink 1.9 when running under kubernetes, but you might need to log into each container and look for them in the logs directory. The kubernetes integration wasn't very mature (or convenient) in 1.9.

Since Flink 1.11 the logs will appear in the Flink web UI, and since 1.12 they're also available via "kubectl logs" by default. See https://issues.apache.org/jira/browse/FLINK-17166 for more info.