Getting 401 Unauthorized error while trying to launch Jenkins slave via command line through JNLP using -secret option

Question

I am trying to launch my Jenkins slave via command line through JNLP, so that I can put the command in the task scheduler. However, I am facing authentication issues only when I use the -secret option with the secret key generated by Jenkins. Works fine if I pass the -auth option with the same username password that I use for Jenkins.

java -jar slave.jar -jnlpUrl http://<jenkins host>:<port>/jenkins/computer/<Slave name>/slave-agent.jnlp -secret <secret_key> -workDir "C:\Jenkins\Robot"

Note: the command I try to execute is as is copied from Jenkins page.

It gives following error:

 org.jenkinsci.remoting.engine.WorkDirManager initializeWorkDirINFO: Using C:\Jenkins\Robot\remoting as a remoting work directory Both error and output logs will be printed to C:\Jenkins\Robot\remoting Not use http_proxy property or environment variable which is invalid: unknown protocol: one.proxy.att.com Failing to obtain http://<host:port>/jenkins/computer/<job>/slave-agent.jnlp?encrypt=true
 java.io.IOException: Failed to load http://<host:port>/jenkins/computer/<job>//slave-agent.jnlp?encrypt=true: 401 Unauthorized
         at hudson.remoting.Launcher.parseJnlpArguments(Launcher.java:485)
         at hudson.remoting.Launcher.run(Launcher.java:316)
         at hudson.remoting.Launcher.main(Launcher.java:277)
 Waiting 10 seconds before retry

However, if I change command as follows, it runs successfully.

java -jar slave.jar -jnlpUrl http://<jenkins host>:<port>/jenkins/computer/<Slave name>/slave-agent.jnlp/slave-agent.jnlp -auth <user>:<pass> -workDir "C:\Jenkins\Robot"

I cannot keep my credentials in the launch file as this will remain in public shared repository. Pls help.

Answer 1

I think that your issue may come from a security management. Have you enable TCP port for JNLP agents in your Global Security ?

Go to Manage Jenkins > Global Security, Enable TCP port for JNLP agents, select Fixed and fill the port you used in your jnlpUrl, then select Java Web Start Agent Protocol/4 and save your config.

Further documentation here.