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Bug
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Resolution: Fixed
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Major
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None
I have a script which does the following:
1) Toggle slave to temporarilyOffline = true
2) Spin up the slave machine
3) Launch the agent with /launchSlaveAgent POST call
4) Wait for the agent to be connected
5) Toggle the slave to temporarilyOffline = false
On step 4) sometimes happens that I get the following error:
Agent successfully connected and online null ERROR: Unexpected error in launching a slave. This is probably a bug in Jenkins. java.lang.NullPointerException at hudson.plugins.sshslaves.SSHLauncher.isRecoverable(SSHLauncher.java:1332) at hudson.plugins.sshslaves.SSHLauncher.openConnection(SSHLauncher.java:1302) at hudson.plugins.sshslaves.SSHLauncher$2.call(SSHLauncher.java:804) at hudson.plugins.sshslaves.SSHLauncher$2.call(SSHLauncher.java:793) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745) [12/13/17 11:31:02] [SSH] Opening SSH connection to 1.1.1.1:22. ERROR: Unexpected error in launching an agent. This is probably a bug in Jenkins java.util.concurrent.CancellationException at java.util.concurrent.FutureTask.report(FutureTask.java:121) at java.util.concurrent.FutureTask.get(FutureTask.java:192) at hudson.plugins.sshslaves.SSHLauncher.launch(SSHLauncher.java:852) at hudson.slaves.SlaveComputer$1.call(SlaveComputer.java:285) at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745)
Why would it state
Agent successfully connected and online
and immediately after throw NPE.
For the moment I've worked around by waiting an extra x seconds before considering the agent actually connected successfully. This seem to have done the job and prevented experiencing errors like:
Hudson.remoting.ChannelClosedException: Remote call on slave1 failed. The channel is closing down or has closed down
Slaves are Google Cloud CentOS 7 machines in the same network as the master.
Jenkins version 2.94
Jenkins SSH Slaves plugin version 1.22
