Permission denied (public key) during fetch from GitHub with Jenkins user on Ubuntu - github

Question

Here is my setup:
Jenkins is running on my linux machine as 'jenkins' user.
I have generated a ssh key-pair as described in Linux - Setup Git, for the 'jenkins' user.
When I sudo su jenkins and try ssh -vT git#github.com, I am always asked my passphrase, but I am always eventually authenicated. (the verbose option shows which key is used, among others).
I could clone my repo from GitHub using jenkins:
Thusly:
jenkins#alpm:~/jobs/test git/workspace$ git pull
Enter passphrase for key '/var/lib/jenkins/.ssh/id*_rsa':
Already up-to-date.
Up to this point I have followed the instructions to the letter. The problem is that the Jenkins job fails with the following error:
status code 128:
stdout:
stderr: Permission denied (publickey).
fatal: The remote end hung up unexpectedly
This is same error as I get when I typo the passphrase (but of course, Jenkins does not ask me for the passphrase). The following pages:
GitHub - SSH Issues
Using SSH Agent Forwarding
indicate to me that ssh-agent could help remember the passphrase, which it does when I am using my own user, but not the jenkins id. Note that while running as my normal user yields:
echo "$SSH_AUTH_SOCK"
/tmp/keyring-nQlwf9/ssh
While running the same command as my 'jenkins' yields nothing (not even permission denied)
My understanding of the problem is that the passphrase is not remembered.
Do you have any idea?
Shall I start a ssh-agent or key ring manager for the jenkins user? How?
Or is ssh forwarding suitable when forwarding to the same machine?
Any brighter idea?
ps: I never sudo gitted, I always used jenkins or my user account (as mentioned in this SO post - Ubuntu/GitHub SSH Key Issue)

Answer 1

Since nobody wrote the answer from the comments for several months, I will quickly do so.
There are 2 possible problems/solutions:
id_rsa created with wrong user
Create id_rsa as the jenkins user (see hudson cannot fetch from git repository)
Leave passphrase empty

Answer 2

To summarise what must be done on the Jenkins server:
# 1. Create the folder containing the SSH keys if necessary
if [ ! -e ~jenkins/.ssh ]; then mkdir ~jenkins/.ssh; fi
cd ~jenkins/.ssh/
# 2. Create the SSH pair of keys
# The comment will help to identify the SSH key on target systems
ssh-keygen -C "jenkins" -f ~jenkins/.ssh/id_rsa -P ""
# 3. Assign the proper access rights
chown -R jenkins ~jenkins/.ssh/
chmod 700 ~jenkins/.ssh
chmod 600 ~jenkins/.ssh/*
Remember:
Please keep the default "id_rsa" name when generating the keys, as other such as "id_rsa_jenkins" won't work, even if correctly set up.
Do not use a passphrase for your key
Check that the public key (id_rsa.pub) has been uploaded on the git server (GitHub, Bitbucket, etc). Once done, test your SSH key by running: ssh -vvv git#github.com (change address according to your git server)

Answer 3

I got around this problem by simply leaving the passphrase empty when creating the keys.

Answer 4

I would add that if you created the keys by hand, they might still be owned by you and not readable by jenkins, try:
sudo chown jenkins -R /var/lib/jenkins/.ssh/*

Answer 5

To check are the following:
if the right public key (id_rsa.pub) is uploaded to the git-server.
jenkins user will access to github -> to CHECK if the right private key (id_rsa) is copied to /var/lib/jenkins/.ssh/
if the known_hosts file is created inside ~/.ssh folder. Try ssh -vvv git#github.com to see debug logs. If thing goes well, github.com will be added to known_hosts.
if the permission of id_rsa is set to 755 (chmod 755 id_rsa)
After all checks -> try ssh -vvv git#github.com
Dont try to do config in jenkins until ssh works!

Answer 6

If you are running jenkins as a service in windows, you need to verify the user running the service. If you created the keys using the user "MACHINENAME\user", change the service so the user running it can match

Answer 7

For Mac users, the issue can be solved by removing the existing keys and creating new Private and Public Keys by following these steps:
1.Remove all Public and Private keys located at /Users/Username/.ssh
2.Remove all the credentials saved under the Credentials tab in Jenkins.
3.Remove the existing Public SSH keys defined in the Github Repository Settings.
4.Create new SSH keys (private and public: id_rsa and id_rsa.pub) by following the steps from https://confluence.atlassian.com/bitbucketserver/creating-ssh-keys-776639788.html#CreatingSSHkeys-CreatinganSSHkeyonLinux&MacOSX
5.Set the newly created public SSH key (id_rsa.pub) in Github or an equivalent Repository Settings.
6.In Jenkins,create new credentials by adding the private SSH key(id_rsa) for your Github username.
7.The Error should be removed now.

Answer 8

keys need to generated from jenkins user.
sudo su jenkins
ssh-keygen
once the key is generated, it should be added as ssh key in bitbucket or github.