[HDFS-13039] StripedBlockReader#createBlockReader leaks socket on IOException

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 3.0.0
• Fix Version/s: 3.1.0, 3.0.1
• Component/s: datanode, erasure-coding
• Target Version/s: 3.1.0, 3.0.1
• Assignee: Lei (Eddy) Xu
• Reporter: Lei (Eddy) Xu
• Created: 19/Jan/18 18:52
• Updated: 22/Jan/18 16:46
• Resolved: 20/Jan/18 01:08

Description

When running EC on one cluster, DataNode has millions of CLOSE_WAIT connections

$ grep CLOSE_WAIT lsof.out | wc -l
10358700

// All CLOSW_WAITs belong to the same DataNode process (pid=88527)
$ grep CLOSE_WAIT lsof.out | awk '{print $2}' | sort | uniq
88527

And DN can not open any file / socket, as shown in the log:

2018-01-19 06:47:09,424 WARN io.netty.channel.DefaultChannelPipeline: An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.
java.io.IOException: Too many open files
        at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method)
        at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:422)
        at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:250)
        at io.netty.channel.socket.nio.NioServerSocketChannel.doReadMessages(NioServerSocketChannel.java:135)
        at io.netty.channel.nio.AbstractNioMessageChannel$NioMessageUnsafe.read(AbstractNioMessageChannel.java:75)
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:563)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:504)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:418)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:390)
        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:742)
        at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:145)
        at java.lang.Thread.run(Thread.java:748)