在 Windows Server 2012 上安装了 Jenkins 1.651 master 和 slave。slave 专用于运行 Selenium 测试，但大多数时候它会离线：
Build step 'Execute Windows batch command' marked build as failure
ERROR: slave-tester is offline; cannot locate jdk7
和
Apr 20, 2016 2:20:05 PM INFO jenkins.slaves.DefaultJnlpSlaveReceiver handle
Disconnecting slave-tester as we are reconnected from the current peer
Apr 20, 2016 2:20:17 PM WARNING org.jenkinsci.remoting.nio.NioChannelHub run
Communication problem
java.io.IOException: An existing connection was forcibly closed by the remote host
at sun.nio.ch.SocketDispatcher.read0(Native Method)
at sun.nio.ch.SocketDispatcher.read(Unknown Source)
at sun.nio.ch.IOUtil.readIntoNativeBuffer(Unknown Source)
at sun.nio.ch.IOUtil.read(Unknown Source)
at sun.nio.ch.SocketChannelImpl.read(Unknown Source)
at org.jenkinsci.remoting.nio.FifoBuffer$Pointer.receive(FifoBuffer.java:136)
at org.jenkinsci.remoting.nio.FifoBuffer.receive(FifoBuffer.java:306)
at org.jenkinsci.remoting.nio.NioChannelHub.run(NioChannelHub.java:561)
at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Apr 20, 2016 2:20:17 PM WARNING jenkins.slaves.JnlpSlaveAgentProtocol$Handler$1 onClosed
NioChannelHub keys=2 gen=88003: Computer.threadPoolForRemoting [#2] for slave-tester terminated
java.io.IOException: Connection aborted: org.jenkinsci.remoting.nio.NioChannelHub$MonoNioTransport@17d0b4b[name=xxx]
at org.jenkinsci.remoting.nio.NioChannelHub$NioTransport.abort(NioChannelHub.java:208)
at org.jenkinsci.remoting.nio.NioChannelHub.run(NioChannelHub.java:628)
at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.io.IOException: An existing connection was forcibly closed by the remote host
at sun.nio.ch.SocketDispatcher.read0(Native Method)
at sun.nio.ch.SocketDispatcher.read(Unknown Source)
at sun.nio.ch.IOUtil.readIntoNativeBuffer(Unknown Source)
at sun.nio.ch.IOUtil.read(Unknown Source)
at sun.nio.ch.SocketChannelImpl.read(Unknown Source)
at org.jenkinsci.remoting.nio.FifoBuffer$Pointer.receive(FifoBuffer.java:136)
at org.jenkinsci.remoting.nio.FifoBuffer.receive(FifoBuffer.java:306)
at org.jenkinsci.remoting.nio.NioChannelHub.run(NioChannelHub.java:561)
... 6 more
从属日志：
<===[JENKINS REMOTING CAPACITY]===>Slave.jar version: 2.53.3
Slave.jar version: 2.53.3
This is a Windows slave
This is a Windows slave
Connection terminated
Connection terminated
ERROR: Failed to install restarter
hudson.remoting.RequestAbortedException: hudson.remoting.Channel$OrderlyShutdown
at hudson.remoting.Request.abort(Request.java:297)
at hudson.remoting.Channel.terminate(Channel.java:847)
at hudson.remoting.Channel$CloseCommand.execute(Channel.java:1080)
at hudson.remoting.Channel$1.handle(Channel.java:501)
at hudson.remoting.AbstractByteArrayCommandTransport$1.handle(AbstractByteArrayCommandTransport.java:61)
at org.jenkinsci.remoting.nio.NioChannelHub$2.run(NioChannelHub.java:594)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at hudson.remoting.SingleLaneExecutorService$1.run(SingleLaneExecutorService.java:112)
at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
at ......remote call to slave-tester(Native Method)
at hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1416)
at hudson.remoting.Request.call(Request.java:172)
at hudson.remoting.Channel.call(Channel.java:780)
at jenkins.slaves.restarter.JnlpSlaveRestarterInstaller.install(JnlpSlaveRestarterInstaller.java:52)
at jenkins.slaves.restarter.JnlpSlaveRestarterInstaller.access$000(JnlpSlaveRestarterInstaller.java:33)
at jenkins.slaves.restarter.JnlpSlaveRestarterInstaller$1.call(JnlpSlaveRestarterInstaller.java:39)
at jenkins.slaves.restarter.JnlpSlaveRestarterInstaller$1.call(JnlpSlaveRestarterInstaller.java:36)
at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: hudson.remoting.Channel$OrderlyShutdown
at hudson.remoting.Channel$CloseCommand.execute(Channel.java:1080)
at hudson.remoting.Channel$1.handle(Channel.java:501)
at hudson.remoting.AbstractByteArrayCommandTransport$1.handle(AbstractByteArrayCommandTransport.java:61)
at org.jenkinsci.remoting.nio.NioChannelHub$2.run(NioChannelHub.java:594)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at hudson.remoting.SingleLaneExecutorService$1.run(SingleLaneExecutorService.java:112)
at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
... 4 more
Caused by: Command close created at
at hudson.remoting.Command.<init>(Command.java:56)
at hudson.remoting.Channel$CloseCommand.<init>(Channel.java:1074)
at hudson.remoting.Channel$CloseCommand.<init>(Channel.java:1072)
at hudson.remoting.Channel.close(Channel.java:1156)
at hudson.remoting.Channel.close(Channel.java:1138)
at hudson.remoting.Channel$CloseCommand.execute(Channel.java:1079)
at hudson.remoting.Channel$1.handle(Channel.java:501)
at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:60)
是什么导致了这个问题以及如何解决它？