Return-Path: X-Original-To: apmail-hadoop-mapreduce-issues-archive@minotaur.apache.org Delivered-To: apmail-hadoop-mapreduce-issues-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 0765618C02 for ; Thu, 10 Sep 2015 19:06:48 +0000 (UTC) Received: (qmail 48006 invoked by uid 500); 10 Sep 2015 19:06:47 -0000 Delivered-To: apmail-hadoop-mapreduce-issues-archive@hadoop.apache.org Received: (qmail 47911 invoked by uid 500); 10 Sep 2015 19:06:47 -0000 Mailing-List: contact mapreduce-issues-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: mapreduce-issues@hadoop.apache.org Delivered-To: mailing list mapreduce-issues@hadoop.apache.org Received: (qmail 47887 invoked by uid 99); 10 Sep 2015 19:06:47 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 10 Sep 2015 19:06:47 +0000 Date: Thu, 10 Sep 2015 19:06:47 +0000 (UTC) From: "Hudson (JIRA)" To: mapreduce-issues@hadoop.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (MAPREDUCE-6474) ShuffleHandler can possibly exhaust nodemanager file descriptors MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/MAPREDUCE-6474?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14739382#comment-14739382 ] Hudson commented on MAPREDUCE-6474: ----------------------------------- FAILURE: Integrated in Hadoop-Yarn-trunk #1106 (See [https://builds.apache.org/job/Hadoop-Yarn-trunk/1106/]) MAPREDUCE-6474. ShuffleHandler can possibly exhaust nodemanager file descriptors. Contributed by Kuhu Shukla (jlowe: rev 8e615588d5216394d0251a9c97bd706537856c6d) * hadoop-mapreduce-project/CHANGES.txt * hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-shuffle/src/test/java/org/apache/hadoop/mapred/TestShuffleHandler.java * hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-shuffle/src/main/java/org/apache/hadoop/mapred/ShuffleHandler.java > ShuffleHandler can possibly exhaust nodemanager file descriptors > ---------------------------------------------------------------- > > Key: MAPREDUCE-6474 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-6474 > Project: Hadoop Map/Reduce > Issue Type: Bug > Components: mrv2, nodemanager > Affects Versions: 2.5.0 > Reporter: Nathan Roberts > Assignee: Kuhu Shukla > Fix For: 2.7.2 > > Attachments: YARN-2410-v1.patch, YARN-2410-v10.patch, YARN-2410-v11.patch, YARN-2410-v2.patch, YARN-2410-v3.patch, YARN-2410-v4.patch, YARN-2410-v5.patch, YARN-2410-v6.patch, YARN-2410-v7.patch, YARN-2410-v8.patch, YARN-2410-v9.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)