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  1. Jenkins
  2. JENKINS-17757

IllegalStateException: Timer already cancelled from NodesCollector.scheduleCollectNow

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      A user reported that his (SSH) slaves repeatedly failed to launch with the following error:

      ...
      Copied classworlds.jar 
      Evacuated stdout 
      ERROR: Unexpected error in launching a slave. This is probably a bug in Jenkins. 
      java.lang.IllegalStateException: Timer already cancelled. 
      at java.util.Timer.sched(Timer.java:397) 
      at java.util.Timer.schedule(Timer.java:193) 
      at net.bull.javamelody.NodesCollector.scheduleCollectNow(NodesCollector.java:110) 
      at org.jvnet.hudson.plugins.monitoring.NodesListener.onOnline(NodesListener.java:51) 
      at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:472) 
      at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:340) 
      at hudson.plugins.sshslaves.SSHLauncher.startSlave(SSHLauncher.java:678) 
      at hudson.plugins.sshslaves.SSHLauncher.launch(SSHLauncher.java:472) 
      at hudson.slaves.SlaveComputer$1.call(SlaveComputer.java:223) 
      at java.util.concurrent.FutureTask$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$Worker.run(ThreadPoolExecutor.java:603) 
      at java.lang.Thread.run(Thread.java:722) 
      […] [SSH] Connection closed. 
      ERROR: Connection terminated 
      java.io.IOException: Unexpected termination of the channel 
      at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:50) 
      Caused by: ...
      

      After disabling the Monitoring plugin the problem went away.

      Not sure what the root cause is, but catching IllegalStateException from scheduleCollectNow and reporting it gracefully with diagnostics seems like a good idea.

      Probably SlaveComputer.setChannel should also be trapping exceptions from listeners it calls. hudson.Util may need a convenience method to call a listener method (as a Runnable? for future lambdas) catching any RuntimeException or LinkageError and politely reporting the error so the caller can continue (maybe even blacklisting the listener for future calls so you do not fill up your log, listing the plugin name and version owning the listener class, etc.).

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              Unassigned Unassigned
              jglick Jesse Glick
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