Windows Jenkins slaves are disconnecting and tunneling port stopped accepting requests

Using Jenkins
,
1

Hi, I’m using Jenkins which
Jenkins version is JENKINS_VERSION 2.375.2
Java version is java.class.version 55.0
https.protocols TLSv1.2
The master node is deployed on an ubuntu server (4.15.0-142-generic #146~16.04.1-Ubuntu)
And connected to agents through tunneling on port 50000, agents are windows and connected to the master using the jnlp command.
Now, all of a sudden some slaves disconnect for the master and when trying to reconnect gives me this error.

May 14, 2023 12:33:47 PM hudson.remoting.jnlp.Main$CuiListener status                                                   INFO: Connecting to <jenkins>:50000 (retrying:7)
java.io.IOException: Failed to connect to <jenkins>:50000 
at org.jenkinsci.remoting.engine.JnlpAgentEndpoint.open(JnlpAgentEndpoint.java:248)                                     at hudson.remoting.Engine.connectTcp(Engine.java:900) 
at hudson.remoting.Engine.innerRun(Engine.java:784) 
at hudson.remoting.Engine.run(Engine.java:543)
Caused by: java.net.ConnectException: Connection refused: connect
at java.base/sun.nio.ch.Net.connect0(Native Method) 
at java.base/sun.nio.ch.Net.connect(Net.java:483) 
at java.base/sun.nio.ch.Net.connect(Net.java:472)
at java.base/sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:692) 
at java.base/java.nio.channels.SocketChannel.open(SocketChannel.java:194)
at org.jenkinsci.remoting.engine.JnlpAgentEndpoint.open(JnlpAgentEndpoint.java:206) 
... 3 more

The master logs are

May 12, 2023 11:34:33 PM INFO jenkins.slaves.DefaultJnlpSlaveReceiver channelClosed
IOHub#1: Worker[channel:java.nio.channels.SocketChannel[connected local=/<ip>:50000 remote=<served>]] / Computer.threadPoolForRemoting [#903] for vsb-5 terminated: java.nio.channels.ClosedChannelException
May 12, 2023 11:41:15 PM INFO jenkins.slaves.DefaultJnlpSlaveReceiver channelClosed
IOHub#1: Worker[channel:java.nio.channels.SocketChannel[connected local=/<ip>:50000 remote=<server>]] / Computer.threadPoolForRemoting [#908] for vsb-4 terminated: java.nio.channels.ClosedChannelException
May 12, 2023 11:43:11 PM INFO hudson.slaves.ChannelPinger$1 onDead
Ping failed. Terminating the channel vsb-3.
java.util.concurrent.TimeoutException: Ping started at 1683927551978 hasn't completed by 1683927791979
	at hudson.remoting.PingThread.ping(PingThread.java:132)
	at hudson.remoting.PingThread.run(PingThread.java:88)

The UI node logs after disconnecting are

Connection was broken

java.nio.channels.ClosedChannelException
	at org.jenkinsci.remoting.protocol.NetworkLayer.onRecvClosed(NetworkLayer.java:155)
	at org.jenkinsci.remoting.protocol.impl.NIONetworkLayer.ready(NIONetworkLayer.java:180)
	at org.jenkinsci.remoting.protocol.IOHub$OnReady.run(IOHub.java:789)
	at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:30)
	at jenkins.security.ImpersonatingExecutorService$1.run(ImpersonatingExecutorService.java:70)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:829)

I checked everything related to the network, and I found that the port is listening on the host but is not listening inside the container.
The server metrics (CPU, RAM) are also good.

2

Hi @Ahmed and welcome to this community :wave: ,

As a reminder, the term “slave” to refer to an agent has been deprecated since 2016. Please refer to On Jenkins Terminology Updates for more details. We request you update your post.

3

Thanks for the heads up. I will update it.

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