Starting slave agents via SSH fails, Ubuntu 12.04

[Zach La Celle]

When I try to start a slave agent on my Ubuntu 12.04 machine (the master is running 14.04), I get the following error:

[10/06/15 16:26:42] [SSH] Starting slave process: cd "/home/build/jenkins-workspace" && java  -jar slave.jar

<===[JENKINS REMOTING CAPACITY]===>channel started

hudson.util.IOException2: Slave JVM has not reported exit code. Is it still running?

at hudson.plugins.sshslaves.SSHLauncher.startSlave(SSHLauncher.java:984)

at hudson.plugins.sshslaves.SSHLauncher.access$400(SSHLauncher.java:137)

at hudson.plugins.sshslaves.SSHLauncher$2.call(SSHLauncher.java:725)

at hudson.plugins.sshslaves.SSHLauncher$2.call(SSHLauncher.java:706)

at java.util.concurrent.FutureTask.run(FutureTask.java:262)

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)

at java.lang.Thread.run(Thread.java:745)

Caused by: java.io.IOException: Remote call on Ubuntu1204-amd64-1 failed

at hudson.remoting.Channel.call(Channel.java:786)

at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:493)

at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:366)

at hudson.plugins.sshslaves.SSHLauncher.startSlave(SSHLauncher.java:976)

... 7 more

Caused by: java.lang.ClassFormatError: Failed to load hudson.slaves.SlaveComputer$SlaveVersion

at hudson.remoting.RemoteClassLoader.loadClassFile(RemoteClassLoader.java:340)

at hudson.remoting.RemoteClassLoader.findClass(RemoteClassLoader.java:251)

at java.lang.ClassLoader.loadClass(ClassLoader.java:323)

at java.lang.ClassLoader.loadClass(ClassLoader.java:268)

at java.lang.Class.forName0(Native Method)

at java.lang.Class.forName(Class.java:274)

at hudson.remoting.MultiClassLoaderSerializer$Input.resolveClass(MultiClassLoaderSerializer.java:113)

at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1611)

at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1516)

at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1770)

at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1349)

at java.io.ObjectInputStream.readObject(ObjectInputStream.java:369)

at hudson.remoting.UserRequest.deserialize(UserRequest.java:185)

at hudson.remoting.UserRequest.perform(UserRequest.java:99)

at hudson.remoting.UserRequest.perform(UserRequest.java:49)

at hudson.remoting.Request$2.run(Request.java:326)

at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:68)

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:1146)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)

at java.lang.Thread.run(Thread.java:701)

at ......remote call to Ubuntu1204-amd64-1(Native Method)

at hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1413)

at hudson.remoting.UserResponse.retrieve(UserRequest.java:221)

at hudson.remoting.Channel.call(Channel.java:778)

... 10 more

Caused by: java.lang.UnsupportedClassVersionError: hudson/slaves/SlaveComputer$SlaveVersion : Unsupported major.minor version 51.0

at java.lang.ClassLoader.defineClass1(Native Method)

at java.lang.ClassLoader.defineClass(ClassLoader.java:643)

at java.lang.ClassLoader.defineClass(ClassLoader.java:489)

at hudson.remoting.RemoteClassLoader.loadClassFile(RemoteClassLoader.java:338)

at hudson.remoting.RemoteClassLoader.findClass(RemoteClassLoader.java:251)

at java.lang.ClassLoader.loadClass(ClassLoader.java:323)

at java.lang.ClassLoader.loadClass(ClassLoader.java:268)

at java.lang.Class.forName0(Native Method)

at java.lang.Class.forName(Class.java:274)

at hudson.remoting.MultiClassLoaderSerializer$Input.resolveClass(MultiClassLoaderSerializer.java:113)

at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1611)

at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1516)

at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1770)

at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1349)

at java.io.ObjectInputStream.readObject(ObjectInputStream.java:369)

at hudson.remoting.UserRequest.deserialize(UserRequest.java:185)

at hudson.remoting.UserRequest.perform(UserRequest.java:99)

at hudson.remoting.UserRequest.perform(UserRequest.java:49)

at hudson.remoting.Request$2.run(Request.java:326)

at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:68)

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:1146)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)

at java.lang.Thread.run(Thread.java:701)

[10/06/15 16:26:47] Launch failed - cleaning up connection

ERROR: Connection terminated

java.io.IOException: Unexpected termination of the channel

at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:50)

[10/06/15 16:26:47] [SSH] Connection closed.

Caused by: java.io.EOFException

at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2332)

at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:2801)

at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:801)

at java.io.ObjectInputStream.<init>(ObjectInputStream.java:299)

at hudson.remoting.ObjectInputStreamEx.<init>(ObjectInputStreamEx.java:40)

at hudson.remoting.AbstractSynchronousByteArrayCommandTransport.read(AbstractSynchronousByteArrayCommandTransport.java:34)

at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:48)..

Any idea what might cause this problem?

[Mark Waite]

The remote machine is probably configured to run a java version which is too old.  For example, you may have Java 6 installed on the Ubuntu 12.04 machine when you need to install Java 7.

If Java 7 is installed on the Ubuntu 12 machine, then you may need to configure the Jenkins slave to run with that java instead of the default Java on the Ubuntu 12 machine.

Mark Waite

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[Zach La Celle]

OK, switching everything to Java 7 seems to have done the trick.  Thank you.

[孟广毅]

yes ,it is  java version is too old on the failed slave ,  you can  see which java used  befor " Starting slave process: cd "/home/build/jenkins-workspace" && java  -jar slave.jar",so you  can modify the JavaPath in the slave config page.

在 2015年10月7日星期三 UTC+8上午4:34:26，Mark Waite写道：