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  1. Jenkins
  2. JENKINS-66446

WebSocket agent does not reconnect: ClassNotFoundException: jenkins.slaves.restarter.JnlpSlaveRestarterInstaller


    • Icon: Bug Bug
    • Resolution: Fixed
    • Icon: Critical Critical
    • Jenkins: 2.303.1
      jenkins k8s controller (master) pod version: jenkins/jenkins:2.289.3-jdk11
      jenkins k8s agent (slave) pod version:  jenkins/inbound-agent:4.9-1-jdk11
      Kubernetes plugin: 1.30.1
    • Jenkins 2.338, Remoting 4.13, 2.332.2

      I'm using jenkins helm chart for my jenkins controller (master) with persistence EFS volume together with Kubernetes plugin with inbound-agent (jdk11) pods for my agents (slaves) over websocket connection

      It seems that the Agent (slave) pods are unable to re-connect the controller (master) after a reboot to the controller (master).

      It seems that the process exit with exit code 0 from some reason instead of reconnecting.


      jenkins controller (master) log

      2021-08-24 13:26:33.976+0000 [id=64]    INFO    o.c.j.p.k.KubernetesLauncher#launch: Agent has already been launched, activating: jenkins-agent-3q3j5


      jenkins agent (slave) log:

      Aug 24, 2021 1:23:56 PM hudson.remoting.Engine lambda$new$1
      Aug 24, 2021 1:23:56 PM hudson.remoting.Engine lambda$new$1SEVERE: Uncaught exception in Engine thread Thread[Thread-0,5,main]
      java.lang.NoClassDefFoundError: jenkins/slaves/restarter/JnlpSlaveRestarterInstaller 
          at jenkins.slaves.restarter.JnlpSlaveRestarterInstaller$FindEffectiveRestarters$1.onReconnect(JnlpSlaveRestarterInstaller.java:91) 
          at hudson.remoting.EngineListenerSplitter.onReconnect(EngineListenerSplitter.java:54) 
          at hudson.remoting.Engine.runWebSocket(Engine.java:687) 
          at hudson.remoting.Engine.run(Engine.java:496)
      Caused by: java.lang.ClassNotFoundException: jenkins.slaves.restarter.JnlpSlaveRestarterInstaller     
          at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:471) 
          at hudson.remoting.RemoteClassLoader.findClass(RemoteClassLoader.java:215)   at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:589) 
          at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522) ... 4 more


      jenkins agent (slave) pod status:

      NAME                              READY   STATUS     RESTARTS   AGE
      jenkins-agent-3q3j5               1/2     NotReady   0          15m
          lastState: {}
          name: jnlp
          ready: false
          restartCount: 0
          started: false
              containerID: docker://9b490eafd5078fa95cbd915bed16bcee767c1005a7a96158a2017d1551fba87b
              exitCode: 0
              finishedAt: "2021-09-08T15:00:07Z"
              reason: Completed
              startedAt: "2021-09-08T14:53:19Z"


       inbound-agent conf

          - name: JENKINS_SECRET
            value: 271983729187392173921798379281739821793b
          - name: JENKINS_AGENT_NAME
            value: jenkins-agent-3q3j5
          - name: DOCKER_HOST
            value: tcp://localhost:2375
          - name: JENKINS_WEB_SOCKET
            value: "true"
          - name: JAVA_OPTS
            value: -Xms512m -Xmx1500m
          - name: JENKINS_NAME
            value: jenkins-agent-3q3j5
          - name: JENKINS_AGENT_WORKDIR
            value: /home/jenkins/agent
          - name: JENKINS_URL
            value: http://jenkins:8080/
          - name: AWS_DEFAULT_REGION
            value: us-east-1
          - name: AWS_REGION
            value: us-east-1
          - name: AWS_ROLE_ARN
            value: arn:aws:iam::123456789:role/jenkins-agent-pod
            value: /var/run/secrets/eks.amazonaws.com/serviceaccount/token


      jenkins agent (slave) pod process

      /opt/java/openjdk/bin/java -Xms512m -Xmx1500m -cp /usr/share/jenkins/agent.jar hudson.remoting.jnlp.Main -headless -url http://jenkins:8080/ -workDir /home /jenkins/agent -webSocket 271983729187392173921798379281739821793b jenkins-agent-3q3j5


      same behavior in



      It seems that this issue happens also on windows agent (slave)


      might be related: https://issues.jenkins.io/browse/JENKINS-59910

            timja Tim Jacomb
            dordor dor s
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