FLINK-14502 we changed how log property files are being discovered by the YarnClusterDescriptor. In fact we moved the responsibility to the FlinkYarnSessionCli. This is problematic because the YarnTestBase creates for Yarn tests a configuration directory which contains the Flink configuration and the log property files. These files are no longer respected because the respective code path has been removed.
I think it is important to fix this problem so that our Yarn tests start to log again. Otherwise it becomes harder to debug Yarn problems and the tests can no longer check for the absence of exceptions in the logs.