[JENKINS-69540] Windows Agents getting disconnected after jenkins restart

Jenkins 2.346.1

EC2 plugin version - 2.0.1 

Windows Agents are hanging at the following after Jenkins restart

Sep 07, 2022 12:08:47 AM hudson.plugins.ec2.EC2Cloud

INFO: Copying remoting.jar to: c:/windows/temp

We tried debugging, but logs didn't indicate anything. This happens 100% of the time and only to windows agents.

After deleting the Agent and recreating new one, it is able to connect to the master. Please note that Windows agents are hanging after Jenkins restart and they cannot reattach.

We haven't noticed same issue happening for Linux agents.

Agent config:



EC2 (EC2 Agent) - WinAgent (i-xxxxxxxxx)

C:\jenkins

1

EXCLUSIVE



-1

180





windows-buildnode



i-xxxxxxxxx



c:/windows/temp

admin

WinAgent

java



false

180

false





jenkins_slave_type

demand_WinAgent





Name

Jenkins-WinAgent





jenkins_server_url

https://jenkins-master.example.com/jenkins/





ec2-EC2 Agent









22





-1

Default

true

false

1

2147483647

 

Logs from the Agent:

Sep 07, 2022 12:10:53 AM hudson.remoting.SynchronousCommandTransport$ReaderThread run

INFO: I/O error in channel channel

java.io.IOException: Unexpected termination of the channel

    at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:75)

Caused by: java.io.EOFException

    at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2681)

    at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:3156)

    at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:862)

    at java.io.ObjectInputStream.(ObjectInputStream.java:358)

    at hudson.remoting.ObjectInputStreamEx.(ObjectInputStreamEx.java:49)

    at hudson.remoting.Command.readFrom(Command.java:142)

    at hudson.remoting.Command.readFrom(Command.java:128)

    at hudson.remoting.AbstractSynchronousByteArrayCommandTransport.read(AbstractSynchronousByteArrayCommandTransport.java:35)

    at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:61)

Any help will be highly appreciated.

Thanks in advance!

---
Originally reported by todori438, imported from: Windows Agents getting disconnected after jenkins restart

• assignee: thoulen
  
• status: Open
  
• priority: Critical
  
• component(s): ec2-plugin
  
• resolution: Unresolved
  
• votes: 0
  
• watchers: 1
  
• imported: 2025-12-06
  

Raw content of original issue

Jenkins 2.346.1 


EC2 plugin version - 2.0.1 


Windows Agents are hanging at the following after Jenkins restart

Sep 07, 2022 12:08:47 AM hudson.plugins.ec2.EC2Cloud

INFO: Copying remoting.jar to: c:/windows/temp


We tried debugging, but logs didn't indicate anything. This happens 100% of the time and only to windows agents.


After deleting the Agent and recreating new one, it is able to connect to the master. Please note that Windows agents are hanging after Jenkins restart and they cannot reattach.


We haven't noticed same issue happening for Linux agents.


Agent config:

<hudson.plugins.ec2.EC2Slave plugin="ec2@2.0.1">

<name>EC2 (EC2 Agent) - WinAgent (i-xxxxxxxxx)</name>

<remoteFS>C:\jenkins</remoteFS>

<numExecutors>1</numExecutors>

<mode>EXCLUSIVE</mode>

<retentionStrategy class="hudson.plugins.ec2.EC2RetentionStrategy">

<nextCheckAfter>-1</nextCheckAfter>

<idleTerminationMinutes>180</idleTerminationMinutes>

</retentionStrategy>

<launcher class="hudson.plugins.ec2.ssh.EC2UnixLauncher"/>

<label>windows-buildnode</label>

<nodeProperties/>

<instanceId>i-xxxxxxxxx</instanceId>

<initScript/>

<tmpDir>c:/windows/temp</tmpDir>

<remoteAdmin>admin</remoteAdmin>

<templateDescription>WinAgent</templateDescription>

<javaPath>java</javaPath>

<jvmopts/>

<stopOnTerminate>false</stopOnTerminate>

<idleTerminationMinutes>180</idleTerminationMinutes>

<isConnected>false</isConnected>

<tags class="linked-list">

<hudson.plugins.ec2.EC2Tag>

<name>jenkins_slave_type</name>

<value>demand_WinAgent</value>

</hudson.plugins.ec2.EC2Tag>

<hudson.plugins.ec2.EC2Tag>

<name>Name</name>

<value>Jenkins-WinAgent</value>

</hudson.plugins.ec2.EC2Tag>

<hudson.plugins.ec2.EC2Tag>

<name>jenkins_server_url</name>

<value>https://jenkins-master.example.com/jenkins/</value>

</hudson.plugins.ec2.EC2Tag>

</tags>

<cloudName>ec2-EC2 Agent</cloudName>

<amiType class="hudson.plugins.ec2.UnixData">

<rootCommandPrefix/>

<slaveCommandPrefix/>

<slaveCommandSuffix/>

<sshPort>22</sshPort>

<bootDelay/>

</amiType>

<maxTotalUses>-1</maxTotalUses>

<tenancy>Default</tenancy>

<metadataEndpointEnabled>true</metadataEndpointEnabled>

<metadataTokensRequired>false</metadataTokensRequired>

<metadataHopsLimit>1</metadataHopsLimit>

<launchTimeout>2147483647</launchTimeout>

</hudson.plugins.ec2.EC2Slave>


 


Logs from the Agent:


Sep 07, 2022 12:10:53 AM hudson.remoting.SynchronousCommandTransport$ReaderThread run

INFO: I/O error in channel channel

java.io.IOException: Unexpected termination of the channel

    at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:75)

Caused by: java.io.EOFException

    at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2681)

    at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:3156)

    at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:862)

    at java.io.ObjectInputStream.<init>(ObjectInputStream.java:358)

    at hudson.remoting.ObjectInputStreamEx.<init>(ObjectInputStreamEx.java:49)

    at hudson.remoting.Command.readFrom(Command.java:142)

    at hudson.remoting.Command.readFrom(Command.java:128)

    at hudson.remoting.AbstractSynchronousByteArrayCommandTransport.read(AbstractSynchronousByteArrayCommandTransport.java:35)

    at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:61)


Any help will be highly appreciated.


Thanks in advance!

Start by reproducing the restart sequence for the Windows EC2 agent and inspect the EC2Cloud log at “Copying remoting.jar to: c:/windows/temp” alongside the hudson.remoting channel error. Compare the Windows behavior with the reported Linux behavior. Done means Windows agents reconnect after a Jenkins restart without deleting and recreating the agent.

Written by the indexing model from the issue text.