netty often reports such exceptions, especially frequently
there are only 3 tcp connections checked, but this exception is reported frequently
error message
java.io.IOException: Connection reset by peer
at sun.nio.ch.FileDispatcherImpl.read0(Native Method) ~[?:1.7.0_55]
at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:39) ~[?:1.7.0_55]
at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223) ~[?:1.7.0_55]
at sun.nio.ch.IOUtil.read(IOUtil.java:192) ~[?:1.7.0_55]
at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:379) ~[?:1.7.0_55]
at io.netty.buffer.UnpooledUnsafeDirectByteBuf.setBytes(UnpooledUnsafeDirectByteBuf.java:447) ~[netty-buffer-4.0.27.Final.jar!/:4.0.27.Final]
at io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:881) ~[netty-buffer-4.0.27.Final.jar!/:4.0.27.Final]
at io.netty.channel.socket.nio.NioSocketChannel.doReadBytes(NioSocketChannel.java:241) ~[netty-transport-4.0.27.Final.jar!/:4.0.27.Final]
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:119) [netty-transport-4.0.27.Final.jar!/:4.0.27.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:511) [netty-transport-4.0.27.Final.jar!/:4.0.27.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:468) [netty-transport-4.0.27.Final.jar!/:4.0.27.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:382) [netty-transport-4.0.27.Final.jar!/:4.0.27.Final]
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:354) [netty-transport-4.0.27.Final.jar!/:4.0.27.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:111) [netty-common-4.0.27.Final.jar!/:4.0.27.Final]
at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:137) [netty-common-4.0.27.Final.jar!/:4.0.27.Final]
at java.lang.Thread.run(Thread.java:745) [?:1.7.0_55]