Just adding some infos for same problem that I previously posted in https://issues.jenkins-ci.org/browse/JENKINS-13869

Hi

I have 3 jenkins Slaves connecting with SSHSlaveAgent and private key : 2 RedHat 6 Linux nodes and 1 Solaris X node.
Updating Jenkins from 1.514 to 1.522, I got now on my Solaris node :

java.io.IOException: Unexpected termination of the channel
at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:50)
Caused by: java.io.EOFException
at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2571)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1315)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:369)
at hudson.remoting.Command.readFrom(Command.java:92)
at hudson.remoting.ClassicCommandTransport.read(ClassicCommandTransport.java:72)
at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:48)

Connecting directly from command line with ssh user@host works well.

My Linux nodes are connected but Jenkins say that clock are not synchronized, 1 day and 1 hour late. However, I'm pretty sure that my master and this nodes have the same time synchronized by a ntp server.

We see here similar problems, time of the slaves is out of sync according to Jenkins with 5 months, but that is not the case. With Solaris 10 x86_64 and Sparc slaves we also have problems connecting using the same error, Solaris 10 ships with "java full version "1.5.0_12-b04". The log when I am using Java webstart:

Jul 24, 2013 1:15:46 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Locating server among [http://jenkins.remedy.nl/]
Jul 24, 2013 1:15:46 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Connecting to jenkins.remedy.nl:45673
Jul 24, 2013 1:15:46 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Handshaking
Jul 24, 2013 1:15:46 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Connected
Jul 24, 2013 1:15:47 PM hudson.remoting.SynchronousCommandTransport$ReaderThread run
SEVERE: I/O error in channel channel
java.io.IOException: Unexpected termination of the channel
        at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:50)
Caused by: java.io.EOFException
        at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2498)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1273)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:348)
        at hudson.remoting.Command.readFrom(Command.java:92)
        at hudson.remoting.ClassicCommandTransport.read(ClassicCommandTransport.java:72)
        at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:48)
Jul 24, 2013 1:15:47 PM hudson.remoting.jnlp.Main$CuiListener status

I tried to upgrade from 1.519 to 1.522 and 1.5.24 and got these same errors. Our system uses linux slaves and this is blocking us from upgrading. Hoping this regression will get fixed in an upcoming release.

Am seeing exact same stack trace for Jenkins 1.525 with a Solaris slave. This slave was working
fine with an older release (not sure of the version). Have a variety of Linux slaves that are all
still working fine. On trying to re-launch slave:

java.io.IOException: Unexpected termination of the channel
at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:50)
Caused by: java.io.EOFException
at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2595)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1315)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:369)
at hudson.remoting.Command.readFrom(Command.java:92)
at hudson.remoting.ClassicCommandTransport.read(ClassicCommandTransport.java:72)
at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:48)

System time problem has been solved in 1.524. The solaris problems seem to come from the fact that JDK 1.5 (default for Solaris 10) is not supported anymore from Jenkins 1.520, installing JDK 7 solved that problem

Updated to 1.526 and following Johnny's suggestion moved to Solaris JDK 1.6. Now works fine.

Updated to 1.526.
Clock synch pb on linux nodes resolved.

Solaris nodes are still offline. This nodes run with JDK6 and $JAVA_HOME is defined and is in $PATH.

java.io.IOException: Unexpected termination of the channel
at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:50)
Caused by: java.io.EOFException
at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2571)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1315)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:369)
at hudson.remoting.Command.readFrom(Command.java:92)
at hudson.remoting.ClassicCommandTransport.read(ClassicCommandTransport.java:72)
at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:48)

However, I found some other logs :
<===[JENKINS REMOTING CAPACITY]===>^@@^@channel started
java.io.IOException: Remote call on IntegrationActivites failed
at hudson.remoting.Channel.call(Channel.java:723)
at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:451)
at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:347)
at hudson.plugins.sshslaves.SSHLauncher.startSlave(SSHLauncher.java:740)
at hudson.plugins.sshslaves.SSHLauncher.launch(SSHLauncher.java:526)
at hudson.slaves.SlaveComputer$1.call(SlaveComputer.java:230)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.ClassFormatError: Failed to load hudson.slaves.SlaveComputer$SlaveVersion
at hudson.remoting.RemoteClassLoader.loadClassFile(RemoteClassLoader.java:299)
at hudson.remoting.RemoteClassLoader.findClass(RemoteClassLoader.java:229)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:242)
at hudson.remoting.MultiClassLoaderSerializer$Input.resolveClass(MultiClassLoaderSerializer.java:113)
at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1544)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1466)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1699)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1305)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:348)
at hudson.remoting.UserRequest.deserialize(UserRequest.java:182)
at hudson.remoting.UserRequest.perform(UserRequest.java:98)
at hudson.remoting.UserRequest.perform(UserRequest.java:48)
at hudson.remoting.Request$2.run(Request.java:326)
at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:72)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:269)
at java.util.concurrent.FutureTask.run(FutureTask.java:123)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:650)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:675)
at java.lang.Thread.run(Thread.java:595)
Caused by: java.lang.UnsupportedClassVersionError: Bad version number in .class file
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
at java.lang.ClassLoader.defineClass(ClassLoader.java:465)
at hudson.remoting.RemoteClassLoader.loadClassFile(RemoteClassLoader.java:297)
... 22 more

So, it seems that command "java -jar slave.jar" runs JDK 5 instead of JDK6. I have to find why, but problem certainly is on my node, not in jenkins or SSHSlave.

EDIT : pb solved for me, PATH & JAVA_HOME was defined in ~/.profile instead of ~/.bashrc.

Some people are reporting that the issue for them was Java 1.5 on the slaves. Can we get confirmation from the original reported that this is the root cause. Otherwise if the original reporter can confirm that this issue is present with Jenkins 1.521 and not with Jenkins 1.520 then I think I know what the root cause may be... but I need confirmation that the issue is only present on/after 1.521 and is resolved with 1.520

I am closing this as inactive.

I have this issue but it doesnt seem related to JAVA, it seems that the connection between the master and slave just breaks, and its random, some jobs pass others will fail.

[info] [info] Wrote instrumentation file [/home/ubuntu/workspace/MYPROJECT/xxx-cloud-storage/target/scala-2.12/scoverage-data/scoverage.coverage.xml][info] [info] Will write measurement data to [/home/ubuntu/workspace/MYPROJECT/xxx-cloud-storage/target/scala-2.12/scoverage-data]FATAL: command execution failedjava.io.EOFException at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2760) at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:3235) at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:914) at java.io.ObjectInputStream.<init>(ObjectInputStream.java:376) at hudson.remoting.ObjectInputStreamEx.<init>(ObjectInputStreamEx.java:49) at hudson.remoting.Command.readFrom(Command.java:142) at hudson.remoting.Command.readFrom(Command.java:128) at hudson.remoting.AbstractSynchronousByteArrayCommandTransport.read(AbstractSynchronousByteArrayCommandTransport.java:35) at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:63)Caused: java.io.IOException: Unexpected termination of the channel at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:77)Caused: java.io.IOException: Backing channel 'EC2 (AWS) - slave (sir-gj1i7kqp)' is disconnected.