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From "Gera Shegalov (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (MAPREDUCE-5672) Provide optional RollingFileAppender for container log4j (syslog)
Date Tue, 07 Jan 2014 23:01:53 GMT

     [ https://issues.apache.org/jira/browse/MAPREDUCE-5672?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Gera Shegalov updated MAPREDUCE-5672:
-------------------------------------

    Attachment: MAPREDUCE-5672.v06.patch

[~jlowe], thanks for the feedback. I removed the dedicated conf for MR-AM from this patch,
and added some doc to mapred-default.xml. 

The point I would make for a dedicated conf for MR-AM is that there are much less AM containers
than MR task attempt containers. You might be interested in always being able to see the full
job in progress log,  but you would be fine with keeping just tails of task attempt logs.
In MRv1, the job  log is in JT and would not be affected by mapreduce.task.userlog.limit.kb.
However, since there is no dedicated limit.kb for AM (though it is certainly not userlog),
this might be worth another JIRA dealing with both settings.

> Provide optional RollingFileAppender for container log4j (syslog)
> -----------------------------------------------------------------
>
>                 Key: MAPREDUCE-5672
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-5672
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>          Components: mr-am, mrv2
>    Affects Versions: 2.2.0
>            Reporter: Gera Shegalov
>            Assignee: Gera Shegalov
>         Attachments: MAPREDUCE-5672.v01.patch, MAPREDUCE-5672.v02.patch, MAPREDUCE-5672.v03.patch,
MAPREDUCE-5672.v04.patch, MAPREDUCE-5672.v05.patch, MAPREDUCE-5672.v06.patch, Screen Shot
2013-12-05 at 3.21.02 PM.png, Screen Shot 2013-12-05 at 3.23.33 PM.png
>
>
> This JIRA is an alternative take on YARN-1130
> We propose providing an option of using a RollingFileAppender(RFA)-based implementation
of container log appender as means of log size control via mapreduce.task.userlog.limit.kb.

> The idea is to use mapreduce.task.userlog.limit.kb as maximumFileSize of RFA. In addition
yarn.app.mapreduce.container.log.backups (task attempt containers) and yarn.app.mapreduce.am.log.backups
(MR-AM) are passed as maxBackupIndex.
> Both current ContainerLogAppender (CLA) and new ContainerRollingLogAppender (CRLA) co-exist.
CLA is the default. CRLA is chosen when  mapreduce.task.userlog.limit.kb > 0 &&
*.backups > 0.
> Pros: 
> 1) CRLA output is visible in UI right away. CLA output with mapreduce.task.userlog.limit.kb
> 0 is not visible until the task attempt finishes that prevents timely diagnostics. 
> 2) Even with excessive logging and a large mapreduce.task.userlog.limit.kb, no space
is taken from the JVM heap.
> 3) No UI impact, since YARN is already designed to deal with any log name beyond stderr/out,
syslog, debug.out, profile.out
> Cons:
> 1) if the logging is excessive there will be more local filesystem metadata I/O due to
roll. That should be negligible in the grand scheme.
> Furthermore, to improve log consistency and completeness in the case of JVM crashes and
SIGTERMing by NM, we propose to restore the MRv1 behavior of periodic log syncing (every 5s)
and having log sync as part of a shutdown hook.
>  



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