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https://issues.apache.org/jira/browse/YARN-4882?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15240489#comment-15240489
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Rohith Sharma K S commented on YARN-4882:
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Apologies for missing your comment. Yes, your understanding is right. Initially
when I raised this JIRA I had in mind that we don't want to flood the logs. But
considering some issues would happen during recovery(would be a bug in RM also)
that helps to know which application recovery caused the failure. This is the
reason I given vote for keeping the logs in separate file.
bq. Are the recovery logs used for anything other than diagnosing a failed
recovery?
AFAIK, completed applications recovery logs used only diagnosis only if
recovery fails. And also helps in debugging for running applications if
applications get hanged or not allocating any containers cases.
> Change the log level to DEBUG for recovering completed applications
> -------------------------------------------------------------------
>
> Key: YARN-4882
> URL: https://issues.apache.org/jira/browse/YARN-4882
> Project: Hadoop YARN
> Issue Type: Bug
> Components: resourcemanager
> Reporter: Rohith Sharma K S
> Assignee: Daniel Templeton
>
> I think for recovering completed applications no need to log as INFO, rather
> it can be made it as DEBUG. The problem seen from large cluster is if any
> issue happens during RM start up and continuously switching , then RM logs
> are filled with most with recovering applications only.
> There are 6 lines are logged for 1 applications as I shown in below logs,
> then consider RM default value for max-completed applications is 10K. So for
> each switch 10K*6=60K lines will be added which is not useful I feel.
> {noformat}
> 2016-03-01 10:20:59,077 INFO
> org.apache.hadoop.yarn.server.resourcemanager.RMAppManager: Default priority
> level is set to application:application_1456298208485_21507
> 2016-03-01 10:20:59,094 INFO
> org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMAppImpl: Recovering
> app: application_1456298208485_21507 with 1 attempts and final state =
> FINISHED
> 2016-03-01 10:20:59,100 INFO
> org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt.RMAppAttemptImpl:
> Recovering attempt: appattempt_1456298208485_21507_000001 with final state:
> FINISHED
> 2016-03-01 10:20:59,107 INFO
> org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt.RMAppAttemptImpl:
> appattempt_1456298208485_21507_000001 State change from NEW to FINISHED
> 2016-03-01 10:20:59,111 INFO
> org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMAppImpl:
> application_1456298208485_21507 State change from NEW to FINISHED
> 2016-03-01 10:20:59,112 INFO
> org.apache.hadoop.yarn.server.resourcemanager.RMAuditLogger: USER=rohith
> OPERATION=Application Finished - Succeeded TARGET=RMAppManager
> RESULT=SUCCESS APPID=application_1456298208485_21507
> {noformat}
> The main problem is missing important information's from the logs before RM
> unstable. Even though log roll back is 50 or 100, in a short period all these
> logs will be rolled out and all the logs contains only RM switching
> information that too recovering applications!!.
> I suggest at least completed applications recovery should be logged as DEBUG.
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