Issue
When I create a new permanent agent with webSocket enabled and Launch method "Launch agent by connecting it to the controller" I get a resulting command which does not include the webSocket option.
Resolution (launcher method)
The webSocket option is not reflected in the command because it is implicit. However, the inbound agent will attempt to connect using webSockets.
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Configure your permanent agent with webSocket enabled and Launch method "Launch agent by connecting it to the controller"
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The resulting command will be presented when accessing your new inbound agent
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From your remote host, run the command (notice: INFO: WebSocket connection open)
java -jar agent.jar -jnlpUrl ${JENKINS_URL}/computer/websocket-agent/jenkins-agent.jnlp -secret ${SECRET} -workDir "/tmp/jenkins" Jan. 29, 2021 9:53:02 A.M. org.jenkinsci.remoting.engine.WorkDirManager initializeWorkDir INFO: Using /tmp/jenkins/remoting as a remoting work directory Jan. 29, 2021 9:53:02 A.M. org.jenkinsci.remoting.engine.WorkDirManager setupLogging INFO: Both error and output logs will be printed to /tmp/jenkins/remoting Jan. 29, 2021 9:53:02 A.M. hudson.remoting.jnlp.Main createEngine INFO: Setting up agent: websocket-agent Jan. 29, 2021 9:53:02 A.M. hudson.remoting.jnlp.Main$CuiListener <init> INFO: Jenkins agent is running in headless mode. Jan. 29, 2021 9:53:02 A.M. hudson.remoting.Engine startEngine INFO: Using Remoting version: 4.5 Jan. 29, 2021 9:53:02 A.M. org.jenkinsci.remoting.engine.WorkDirManager initializeWorkDir INFO: Using /tmp/jenkins/remoting as a remoting work directory Jan. 29, 2021 9:53:02 A.M. hudson.remoting.jnlp.Main$CuiListener status INFO: WebSocket connection open Jan. 29, 2021 9:53:02 A.M. hudson.remoting.jnlp.Main$CuiListener status INFO: Connected
Alternative (raw method)
If you’re not seeing a "WebSocket connection open" while using the implicit launcher method (above) please ensure you are using the latest "agent.jar" and use the raw method and pass -webSocket explicitly to the command.
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Re-download agent.jar
$ curl -OL https://127.0.0.1:8080/jnlpJars/agent.jar % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 1485k 100 1485k 0 0 207M 0 --:--:-- --:--:-- --:--:-- 207M $ $ ls -l agent.jar -rw-r--r-- 1 me staff 1521553 29 Jan 10:17 agent.jar $ $ md5sum agent.jar d866f0b482db94f38e49b26b465d5db5 agent.jar $ -
Verify agent.jar version
$ java -jar agent.jar -version 4.5 $
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Use the raw method for launching agent with webSocket option
$ java -cp agent.jar hudson.remoting.jnlp.Main -url ${JENKINS_URL} -webSocket -workDir /tmp/jenkins -secret ${TOKEN} websocket-agent Jan. 29, 2021 10:10:15 A.M. hudson.remoting.jnlp.Main createEngine INFO: Setting up agent: websocket-agent Jan. 29, 2021 10:10:18 A.M. hudson.remoting.Engine startEngine INFO: Using Remoting version: 4.5 Jan. 29, 2021 10:10:18 A.M. org.jenkinsci.remoting.engine.WorkDirManager initializeWorkDir INFO: Using /tmp/jenkins/remoting as a remoting work directory Jan. 29, 2021 10:10:18 A.M. org.jenkinsci.remoting.engine.WorkDirManager setupLogging INFO: Both error and output logs will be printed to /tmp/jenkins/remoting $