How to enable debug level logging for YARN and its dependent services

Summery: How to enable debug level logging for YARN and its dependent services without restart.

Explanation: 

you may not be able to identify issue when INFO level logging is enabled while troubleshooting issue. in-order to see more granular logging we  have to enable DEBUG mode logging for different YARN services.

         Below steps helps you to configure this in Production environments without YARN service restart.

Steps:

1)  Open 'resource manager'  web interface.

Ex: http://<your rm ip>:8080  (you should see screen similar to below)

2) Now open logging configuration web page from RM web page.

ex: http://<your rm ip>:8080/logLevel ( you should see below web page)

(take a note uppercase L in URL).

 

3) Now decide, for which log class you want to change logging level.

Ex: i am choosing 'RMAuditLogger'.

4) Check what is the current logging level for chosen class.(check screen shot)

5) Now, change the logging level for chosen classes to desired logging level (in this case INFO to DEBUG)

6) Review the Resource Manager service log. After the change, you should see the DEBUG level log messages in the logs.