Controller to agent connectivity failure on UI

I am getting the below error when trying to launch an agent from the Jenkins UI
Troubleshooting performed,
Verified the SSH keys on the Master and agent for the user.
Error message on the UI:

ERROR: Server rejected the 1 private key(s) for user1 (credentialId:xxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/method:publickey)
[01/19/17 05:35:15] [SSH] Authentication failed.
hudson.AbortException: Authentication failed.

Environement setup : Jenkins Version 2.346.1

Our Jenkins servers are patched with
[root]# ssh -V
OpenSSH_8.8p1 (CentrifyDC build 5.8.1-367) , OpenSSL 3.0.1 14 Dec 2021

Note: All SSH keys are verified. The remoting.jar file is temporarily deleted and tried multiple times to relaunch the application.

Hi there,

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.

Mark Waite

@MarkEWaite , thanks for the correction, may I know if there is a workaround for the above problem, thanks!

I was also able to figure out that the /home/usrname/.ssh that contains the is an “ssh-rsa” that is deprecated with the openssh8.8. Any ideas if creating an ssh-keygen with a different cipher (sha256, sha512) would help the Master and Agent communicate successfully over the Jenkins UI

Generate a new key. I prefer ED-25519 keys because the text of the key is shorter and easier to copy and paste.

Please also use “Controller” instead of “master”.

The OpenSSH project dropped support for that type of key because they consider that they are not sufficiently secure for current environments.

1 Like

Apologies about the terminology. Noted!!
Thanks for the suggestion :slight_smile:

1 Like