"WARNING: Failed to construct Command" when dynamic slave is terminated

[Mark Petrovic]

I am developing a cloud plugin that spins up nodes on demand to build projects inside Docker containers.

Everything is worked well, but I see these exceptions in the log when a node finishes its job and I _terminate it:

Jul 18, 2015 5:41:21 PM hudson.model.Run execute

INFO: boot-continuous-develop #15 main build action completed: SUCCESS

Jul 18, 2015 5:41:21 PM com.xoom.inf.jenkins.plugins.KubernetesSlave _terminate

INFO: Terminating Kubernetes instance for slave 25cf5bd9-1bb8-468a-bca3-faeba0a84bde

Jul 18, 2015 5:41:22 PM com.xoom.inf.jenkins.plugins.KubernetesSlave _terminate

INFO: Terminated Kubernetes instance for slave 25cf5bd9-1bb8-468a-bca3-faeba0a84bde

Jul 18, 2015 5:41:22 PM hudson.remoting.AbstractByteArrayCommandTransport$1 handle

WARNING: Failed to construct Command

java.io.EOFException

        at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2328)

        at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:2797)

        at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:802)

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

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

        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(Executors.java:511)

        at java.util.concurrent.FutureTask.run(FutureTask.java:266)

        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(Executors.java:511)

        at java.util.concurrent.FutureTask.run(FutureTask.java:266)

        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)

        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

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

What does this mean and how can I prevent this?  

Thank you.

[Mark Petrovic]

A little more information:  here is how the AbstractCloudSlave._terminate() method is implemented in my custom slave:

    @Override

    protected void _terminate(TaskListener listener) throws IOException, InterruptedException {

        LOGGER.log(Level.INFO, "Terminating Kubernetes instance for slave {0}", name);

        try {

            cloud.client().deletePod(name, KubernetesCloud.POD_NAMESPACE);

            LOGGER.log(Level.INFO, "Terminated Kubernetes instance for slave {0}", name);

            toComputer().disconnect(null);

        } catch (Exception e) {

            LOGGER.log(Level.SEVERE, "Failure to terminate instance for slave " + name, e);

        }

    }

I'm wondering if the toComputer().disconnect(null) is appropriate.  

[Mark Petrovic]

And a bit more information...

Here is another stacktrace that occurs when jobs finish:

Jul 28, 2015 3:56:29 PM jenkins.slaves.JnlpSlaveAgentProtocol$Handler$1 onClosed

WARNING: Computer.threadPoolForRemoting [#75] for ac027ba0-74df-4d1d-a92c-1bca931c61d1 terminated

java.io.EOFException

at org.jenkinsci.remoting.nio.NioChannelHub$3.run(NioChannelHub.java:613)

at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)

at java.util.concurrent.FutureTask.run(FutureTask.java:266)

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(Executors.java:511)

at java.util.concurrent.FutureTask.run(FutureTask.java:266)

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

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

I am working in a fork of the Jenkins Kubernetes plugin, which I should have said at the outset.  

https://github.com/jenkinsci/kubernetes-plugin

Beyond these exceptions, the plugin otherwise works fine.

I'm concerned that if I deploy this plugin to support a production build farm, these exceptions may indicate a condition in the master that will lead to memory leaks or some such.  iow, can I safely ignore these exceptions (which I really hate to do).