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  1. Jenkins
  2. JENKINS-63804

master to agent connection keeps breaking every 3-4 hours

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    • Icon: Bug Bug
    • Resolution: Unresolved
    • Icon: Critical Critical
    • remoting
    • None
    • Jenkins: 2.249.1
      Master Node: Linux RHEL 8.1
      Master Java Version: 1.8.0_242
      Slave System: macOS Catalina, Version 10.15.6
      Slave Java Version: 1.8.0_261

       

      Hi Team, We are using JNLP to connect Mac agent to Linux master node.

      Jenkins agent keeps disconnecting frequently, and we are getting below logs in master.

      Can you please suggest how to resolve this? What are the steps to further triage the same.

      Some of the questions we are trying to answer is:

      • What is EOFException?
      • Why does agent tries to connect to master when its already connected?
      • Why does eventually the ping / connection fails?

       

      We keep seeing this pattern in logs too often and too frequently. Any help would be appreciated.

      Results are same even if we try any of the below options:

      • Connected using Launch agent from Browser
      • Connected by starting automator in Mac which runs shell/zsh to run agent.jar
      • Connected by running plist in Mac

       

      Connection #xxx failed: java.io.EOFException
      Sep 29, 2020 2:45:21 AM 
      INFO hudson.TcpSlaveAgentListener$ConnectionHandler run
      Accepted JNLP4-connect connection #xxx from x.x.x.x/x.x.x.x:57215
      Sep 29, 2020 2:45:21 AM 
      INFO org.jenkinsci.remoting.protocol.impl.ConnectionHeadersFilterLayer on
      Recv[JNLP4-connect connection from x.x.x.x/x.x.x.x:57215] 
      Refusing headers from remote: <agent_name> is already connected to this master. 
      Rejecting this connection.Sep 29, 2020 2:45:31 AM 
      INFO hudson.TcpSlaveAgentListener$ConnectionHandler runConnection #xxx failed: java.io.EOFException
      Sep 29, 2020 2:45:31 AM INFO hudson.TcpSlaveAgentListener$ConnectionHandler runAccepted JNLP4-connect connection #xxx from x.x.x.x/x.x.x.x:57218
      Sep 29, 2020 2:45:32 AM 
      INFO org.jenkinsci.remoting.protocol.impl.ConnectionHeadersFilterLayer onRecv[JNLP4-connect connection from x.x.x.x/x.x.x.x] Refusing headers from remote: <agent_name> is already connected to this master. 
      Rejecting this connection.Sep 29, 2020 2:45:32 AM INFO hudson.slaves.ChannelPinger$1 onDeadPing failed. Terminating the channel JNLP4-connect connection from x.x.x.x/x.x.x.x:57015.
      java.util.concurrent.TimeoutException: Ping started at 1601318492966 hasn't completed by 1601318732966        at hudson.remoting.PingThread.ping(PingThread.java:134)        at hudson.remoting.PingThread.run(PingThread.java:90)
      

       

       

            Unassigned Unassigned
            ashisharma888 Ashish Sharma
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              Created:
              Updated: