In UserGroupInformation::doAs(), it prints out a log at ERROR level whenever it catches an exception.
However, it prints benign warnings in the following paradigm:
For example, FileSystem#exists() follows this paradigm. Distcp uses this paradigm too. The exception is expected therefore there should be no ERROR logs printed in the namenode logs.
Currently, the user quickly finds out that the namenode log is quickly filled by benign ERROR logs when he or she runs distcp in secure set up. This behavior confuses the operators.
This jira proposes to move the log to DEBUG level.