[MAPREDUCE-7156] NullPointerException when reaching max shuffle connections

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.9.1, 3.1.1
• Fix Version/s: 2.10.0, 3.0.4, 3.1.2, 2.8.6, 3.3.0, 3.2.1, 2.9.3
• Component/s: mrv2
• Hadoop Flags: Reviewed
• Assignee: Peter Bacsko
• Reporter: Peter Bacsko
• Created: 31/Oct/18 10:38
• Updated: 07/Nov/18 00:19
• Resolved: 07/Nov/18 00:19

Description

When you hit the max number of shuffle connections, you can get a lot of NullPointerExceptions from Netty:

2018-07-17 10:47:36,311 INFO org.apache.hadoop.mapred.ShuffleHandler: Current number of shuffle connections (360) is greater than or equal to the max allowed shuffle connections (360)
2018-07-17 10:47:36,311 INFO org.apache.hadoop.mapred.ShuffleHandler: Current number of shuffle connections (360) is greater than or equal to the max allowed shuffle connections (360)
2018-07-17 10:47:36,312 INFO org.apache.hadoop.mapred.ShuffleHandler: Current number of shuffle connections (360) is greater than or equal to the max allowed shuffle connections (360)
2018-07-17 10:47:36,316 ERROR org.apache.hadoop.mapred.ShuffleHandler: Shuffle error:
java.lang.NullPointerException
2018-07-17 10:47:36,317 ERROR org.apache.hadoop.mapred.ShuffleHandler: Shuffle error [id: 0x71187405, /10.17.226.11:44330 => /10.17.202.21:13562] EXCEPTION: java.lang.NullPointerException
2018-07-17 10:47:36,317 ERROR org.apache.hadoop.mapred.ShuffleHandler: Shuffle error:
java.lang.NullPointerException
2018-07-17 10:47:36,317 ERROR org.apache.hadoop.mapred.ShuffleHandler: Shuffle error [id: 0x71187405, /10.17.226.11:44330 => /10.17.202.21:13562] EXCEPTION: java.lang.NullPointerException
2018-07-17 10:47:36,317 ERROR org.apache.hadoop.mapred.ShuffleHandler: Shuffle error:
java.lang.NullPointerException
2018-07-17 10:47:36,317 ERROR org.apache.hadoop.mapred.ShuffleHandler: Shuffle error [id: 0x71187405, /10.17.226.11:44330 => /10.17.202.21:13562] EXCEPTION: java.lang.NullPointerException
2018-07-17 10:47:36,329 INFO org.apache.hadoop.yarn.server.nodemanager.containermanager.monitor.ContainersMonitorImpl: Skipping monitoring container container_e22_1531424278071_55040_01_002295 since CPU usage is not yet available.
2018-07-17 10:47:36,340 ERROR org.apache.hadoop.mapred.ShuffleHandler: Shuffle error:
java.lang.NullPointerException
2018-07-17 10:47:36,340 ERROR org.apache.hadoop.mapred.ShuffleHandler: Shuffle error [id: 0xea8afd26, /10.17.202.18:43810 => /10.17.202.21:13562] EXCEPTION: java.lang.NullPointerException
2018-07-17 10:47:36,349 ERROR org.apache.hadoop.mapred.ShuffleHandler: Shuffle error:
java.lang.NullPointerException
2018-07-17 10:47:36,349 ERROR org.apache.hadoop.mapred.ShuffleHandler: Shuffle error [id: 0xea8afd26, /10.17.202.18:43810 => /10.17.202.21:13562] EXCEPTION: java.lang.NullPointerException
2018-07-17 10:47:36,349 ERROR org.apache.hadoop.mapred.ShuffleHandler: Shuffle error:
java.lang.NullPointerException
2018-07-17 10:47:36,349 ERROR org.apache.hadoop.mapred.ShuffleHandler: Shuffle error [id: 0xea8afd26, /10.17.202.18:43810 => /10.17.202.21:13562] EXCEPTION: java.lang.NullPointerException
2018-07-17 10:47:36,361 INFO org.apache.hadoop.mapred.ShuffleHandler: Current number of shuffle connections (360) is greater than or equal to the max allowed shuffle connections (360)
2018-07-17 10:47:36,390 INFO org.apache.hadoop.mapred.ShuffleHandler: Current number of shuffle connections (360) is greater than or equal to the max allowed shuffle connections (360)
2018-07-17 10:47:36,395 ERROR org.apache.hadoop.mapred.ShuffleHandler: Shuffle error:

2018-07-17 13:58:28,263 INFO org.apache.hadoop.mapred.ShuffleHandler: Current number of shuffle connections (360) is greater than or equal to the max allowed shuffle connections (360)
2018-07-17 13:58:28,264 ERROR org.apache.hadoop.mapred.ShuffleHandler: Shuffle error:
java.lang.NullPointerException
        at org.jboss.netty.handler.timeout.IdleStateHandler.writeComplete(IdleStateHandler.java:302)
        at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:73)
        at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
        at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)
        at org.jboss.netty.channel.SimpleChannelUpstreamHandler.writeComplete(SimpleChannelUpstreamHandler.java:233)
        at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:73)
        at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
        at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)
        at org.jboss.netty.handler.stream.ChunkedWriteHandler.handleUpstream(ChunkedWriteHandler.java:142)
        at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
        at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)
        at org.jboss.netty.channel.SimpleChannelUpstreamHandler.writeComplete(SimpleChannelUpstreamHandler.java:233)
        at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:73)
        at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
        at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)
        at org.jboss.netty.channel.SimpleChannelUpstreamHandler.writeComplete(SimpleChannelUpstreamHandler.java:233)
        at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:73)
        at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
        at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)
        at org.jboss.netty.channel.SimpleChannelUpstreamHandler.writeComplete(SimpleChannelUpstreamHandler.java:233)
        at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:73)
        at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
        at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:559)
        at org.jboss.netty.channel.Channels.fireWriteComplete(Channels.java:324)
        at org.jboss.netty.channel.socket.nio.AbstractNioWorker.write0(AbstractNioWorker.java:299)
        at org.jboss.netty.channel.socket.nio.AbstractNioWorker.writeFromUserCode(AbstractNioWorker.java:146)
        at org.jboss.netty.channel.socket.nio.NioServerSocketPipelineSink.handleAcceptedSocket(NioServerSocketPipelineSink.java:99)
        at org.jboss.netty.channel.socket.nio.NioServerSocketPipelineSink.eventSunk(NioServerSocketPipelineSink.java:36)
        at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendDownstream(DefaultChannelPipeline.java:779)
        at org.jboss.netty.channel.Channels.write(Channels.java:725)
        at org.jboss.netty.channel.Channels.write(Channels.java:686)
        at org.jboss.netty.handler.ssl.SslHandler.wrapNonAppData(SslHandler.java:1110)
        at org.jboss.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:1252)
        at org.jboss.netty.handler.ssl.SslHandler.decode(SslHandler.java:852)
        at org.jboss.netty.handler.codec.frame.FrameDecoder.callDecode(FrameDecoder.java:425)
        at org.jboss.netty.handler.codec.frame.FrameDecoder.messageReceived(FrameDecoder.java:303)
        at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:70)
        at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
        at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:559)
        at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:268)
        at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:255)
        at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:88)
        at org.jboss.netty.channel.socket.nio.AbstractNioWorker.process(AbstractNioWorker.java:108)
        at org.jboss.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:337)
        at org.jboss.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:89)
        at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:178)
        at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108)
        at org.jboss.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)

Solutions seems to be an one-liner: you have to call super.channelOpen(ctx, evt); in Shuffle.channelOpen() in both cases. If we don't do this, then IdleStateHandler will not be initialized properly and will get a null attachment object when executing writeComplete().