I've installed Jenkins in an Ubuntu server by following the documentation from Jenkins Install documentation and I am trying to set up Gerrit Trigger Plugin. While setting up Administrative Settings section the SSH Keyfile section always gives the error "/var/lib/jenkins/.ssh/id_rsa" is not a valid key file.
I've generated the ssh keys as the Jenkins user in the default location "/var/lib/jenkins/"
I've tried generating the keys with ssh-keygen, ssh-keygen -t rsa, ssh-keygen -t rsa -b 2048 and the keys are generated with and without a passphrase also as pem file but still shows as invalid key file.
The files are present in the "/var/lib/jenkins/.ssh/" location
jenkins@jenkins:~/.ssh$ ls -la
total 16
drwx------ 2 jenkins jenkins 4096 Oct 9 14:18 .
drwxr-xr-x 17 jenkins jenkins 4096 Oct 9 14:18 ..
-rw------- 1 jenkins jenkins 2602 Oct 9 14:05 id_rsa
-rw-r--r-- 1 jenkins jenkins 569 Oct 9 14:05 id_rsa.pub
I didn't find any log entries regarding this in jenkins log file also not in the web portal System Log section.
Try to generate the key with the following command:
ssh-keygen -m PEM