Jenkins pipeline not correctly using sshagent credentials - jenkins

Question

I have this code snippet that has to use a custom private key from the Jenkins credentials using the ssh-agent-plugin.
This doesn't seem to work, but it also doesn't print a very useful output.
Any ideas how to debug this?
stage('Test Git') {
steps {
sshagent(credentials : ['denpal']) {
sh 'git commit --allow-empty -m "test withCredentials"'
sh 'git push origin feature/Jenkinsfile'
}
[Pipeline] // stage
[Pipeline] stage
[Pipeline] { (Test Git)
[Pipeline] sshagent
[ssh-agent] Using credentials git (denpal)
[ssh-agent] Looking for ssh-agent implementation...
[ssh-agent] Exec ssh-agent (binary ssh-agent on a remote machine)
$ ssh-agent
SSH_AUTH_SOCK=/tmp/ssh-WEsIsQvX4CFc/agent.12163
SSH_AGENT_PID=12166
Running ssh-add (command line suppressed)
[Pipeline] // sshagent
[Pipeline] }

Answer 1

I had the same problem trying to push code to my repo from Jenkins.
I found the solution here: https://www.reddit.com/r/docker/comments/b8lmc4/jenkins_pipeline_not_correctly_using_sshagent/
I replaced the sshagent code block with:
withCredentials([sshUserPrivateKey(credentialsId: 'myCredentials', keyFileVariable: 'KEY_FILE')]) {
sh "eval `ssh-agent -s` && ssh-add ${KEY_FILE} && ssh-add -L && git push -u origin develop"
}
It worked for me.