Cannot SSH into Jenkins-cli

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1

When I ssh (I am using Windows 10 with OpenSSH) into jenkins-cli.jar I get the following error:

Jan 05, 2023 12:48:06 PM io.jenkins.cli.shaded.org.apache.sshd.common.util.security.AbstractSecurityProviderRegistrar getOrCreateProvider
INFO: getOrCreateProvider(EdDSA) created instance of io.jenkins.cli.shaded.net.i2p.crypto.eddsa.EdDSASecurityProvider
Jan 05, 2023 12:48:07 PM io.jenkins.cli.shaded.org.apache.sshd.common.io.DefaultIoServiceFactoryFactory getIoServiceProvider
INFO: No detected/configured IoServiceFactoryFactory; using Nio2ServiceFactoryFactory
io.jenkins.cli.shaded.org.apache.sshd.common.RuntimeSshException: Failed to get the session.
        at io.jenkins.cli.shaded.org.apache.sshd.client.future.DefaultConnectFuture.getSession(DefaultConnectFuture.java:59)
        at io.jenkins.cli.shaded.org.apache.sshd.client.future.DefaultConnectFuture.getSession(DefaultConnectFuture.java:34)
        at hudson.cli.SSHCLI.sshConnection(SSHCLI.java:102)
        at hudson.cli.CLI._main(CLI.java:294)
        at hudson.cli.CLI.main(CLI.java:103)
Caused by: java.io.IOException: The semaphore timeout period has expired
        at java.base/sun.nio.ch.Iocp.translateErrorToIOException(Iocp.java:299)
        at java.base/sun.nio.ch.Iocp$EventHandlerTask.run(Iocp.java:389)
        at java.base/java.lang.Thread.run(Thread.java:1589)

After trying:

java -jar jenkins-cli.jar -s SERVER:8080/ -ssh -user MY_USERNAME

What is the cause of this error, so that I can fix it and SSH into my jenkins instance?

2

Hello @emimri and welcome to this community :wave:

What version of Jenkins are you running?
Your controller is running on Windows, am I right?
What is your Java version?
What is the operating system your Jenkins agent is running?
What is its operating system?

What are you trying to achieve? Link a Jenkins agent from the controller to the agent through ssh ?

Please have a look at Using Jenkins agents .

3

Hello Bruno,

Not sure whether I can answer all your questions accurately.

I have been granted permission to have access to Jenkins, I believe the controller is someone else in my business. I am using windows 10, but have all access/permissions in Jenkins.

We’re running Jenkins on a server, but I am attempting to ssh into Jenkins following this documentation: Jenkins CLI

I am using Java:

java version "19.0.1" 2022-10-18
Java(TM) SE Runtime Environment (build 19.0.1+10-21)
Java HotSpot(TM) 64-Bit Server VM (build 19.0.1+10-21, mixed mode, sharing)

The operating system is Linux:

os.version: 3.10.0-1160.53.1.el7.x86_64

The Jenkins is using Java 11 version 55.

I was going to attempt to SSH into Jenkins and sudo apt-get install a package with admin permissions, because I cannot do this in the shell. Unless, there is an alternative approach?

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4

Is there an HTTP reverse proxy between your machine and the Jenkins controller?
Is there a firewall?
Are the ssh ports authorized?

5

Well our jenkins server runs on a VPN, and it’s only available as an application on the browser when the VPN is on.

I have attempted the link you have provided with using Jenkins agents. Although, I attempted this on my mac os, which does not have vpn access to our jenkins server. However, my windows PC does, would I still get SSH access to jenkins with this approach?

After some extra research:

  1. My windows environment lacks administration privileges, therefore, this could be blocking the SSH access.
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6

I have no idea on what’s blocking the ssh connection, but so that you do not loose to much time to pursue something that won’t work in the end:

I was going to attempt to SSH into Jenkins and sudo apt-get install a package with admin permissions, because I cannot do this in the shell.

This is not what the ssh mode of the Jenkins-cli will bring you. It just use ssh to communicate with Jenkins to run jenkins-cli commands (like trigger a job, get the result of a job etc…) but it won’t open a shell to the machine running Jenkins.

7

Ah I see! It’s possible I am blocked by a company firewall that prevents the SSH connection from going through successfully.

Additionally, by what other means can I successfully sudo install files, or can this only be granted by the controller who has access to the Jenkins files to modify ROOT access for users?

8

by what other means can I successfully sudo install files

You need to ask your ops team an access to the machine with proper permissions.

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