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Hadoop QA commented on YARN-2410: --------------------------------- \\ \\ | (x) *{color:red}-1 overall{color}* | \\ \\ || Vote || Subsystem || Runtime || Comment || | {color:blue}0{color} | pre-patch | 15m 36s | Pre-patch trunk compilation is healthy. | | {color:green}+1{color} | @author | 0m 0s | The patch does not contain any @author tags. | | {color:green}+1{color} | tests included | 0m 0s | The patch appears to include 1 new or modified test files. | | {color:green}+1{color} | javac | 7m 50s | There were no new javac warning messages. | | {color:green}+1{color} | javadoc | 9m 43s | There were no new javadoc warning messages. | | {color:green}+1{color} | release audit | 0m 23s | The applied patch does not increase the total number of release audit warnings. | | {color:red}-1{color} | checkstyle | 0m 20s | The applied patch generated 19 new checkstyle issues (total was 60, now 79). | | {color:green}+1{color} | whitespace | 0m 0s | The patch has no lines that end in whitespace. | | {color:green}+1{color} | install | 1m 21s | mvn install still works. | | {color:green}+1{color} | eclipse:eclipse | 0m 34s | The patch built with eclipse:eclipse. | | {color:red}-1{color} | findbugs | 0m 47s | The patch appears to introduce 1 new Findbugs (version 3.0.0) warnings. | | {color:green}+1{color} | mapreduce tests | 0m 21s | Tests passed in hadoop-mapreduce-client-shuffle. | | | | 36m 58s | | \\ \\ || Reason || Tests || | FindBugs | module:hadoop-mapreduce-client-shuffle | \\ \\ || Subsystem || Report/Notes || | Patch URL | http://issues.apache.org/jira/secure/attachment/12747256/YARN-2410-v4.patch | | Optional Tests | javadoc javac unit findbugs checkstyle | | git revision | trunk / 156f24e | | checkstyle | https://builds.apache.org/job/PreCommit-YARN-Build/8676/artifact/patchprocess/diffcheckstylehadoop-mapreduce-client-shuffle.txt | | Findbugs warnings | https://builds.apache.org/job/PreCommit-YARN-Build/8676/artifact/patchprocess/newPatchFindbugsWarningshadoop-mapreduce-client-shuffle.html | | hadoop-mapreduce-client-shuffle test log | https://builds.apache.org/job/PreCommit-YARN-Build/8676/artifact/patchprocess/testrun_hadoop-mapreduce-client-shuffle.txt | | Test Results | https://builds.apache.org/job/PreCommit-YARN-Build/8676/testReport/ | | Java | 1.7.0_55 | | uname | Linux asf905.gq1.ygridcore.net 3.13.0-36-lowlatency #63-Ubuntu SMP PREEMPT Wed Sep 3 21:56:12 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux | | Console output | https://builds.apache.org/job/PreCommit-YARN-Build/8676/console | This message was automatically generated. > Nodemanager ShuffleHandler can possible exhaust file descriptors > ---------------------------------------------------------------- > > Key: YARN-2410 > URL: https://issues.apache.org/jira/browse/YARN-2410 > Project: Hadoop YARN > Issue Type: Bug > Components: nodemanager > Affects Versions: 2.5.0 > Reporter: Nathan Roberts > Assignee: Kuhu Shukla > Fix For: 2.7.2 > > Attachments: YARN-2410-v1.patch, YARN-2410-v2.patch, > YARN-2410-v3.patch, YARN-2410-v4.patch > > > The async nature of the shufflehandler can cause it to open a huge number of > file descriptors, when it runs out it crashes. > Scenario: > Job with 6K reduces, slow start set to 0.95, about 40 map outputs per node. > Let's say all 6K reduces hit a node at about same time asking for their > outputs. Each reducer will ask for all 40 map outputs over a single socket in > a > single request (not necessarily all 40 at once, but with coalescing it is > likely to be a large number). > sendMapOutput() will open the file for random reading and then perform an > async transfer of the particular portion of this file(). This will > theoretically > happen 6000*40=240000 times which will run the NM out of file descriptors and > cause it to crash. > The algorithm should be refactored a little to not open the fds until they're > actually needed. -- This message was sent by Atlassian JIRA (v6.3.4#6332)