<p>I am attempting to use sshagent in Jenkins to pass my private key into the terraform container to allow terraform to source a module in a private repo. </p>

<pre><code>stage('TF Plan') {
  steps {
    container('terraform') {
      sshagent (credentials: ['6c92998a-bbc4-4f27-b925-b50c861ef113']){
        sh 'ssh-add -L'
        sh 'terraform init'
        sh 'terraform plan -out myplan'
      }
    }
  }      
}
</code></pre>

<p>When running the job it fails with the following output:</p>

<pre><code>[ssh-agent] Using credentials (id_rsa_jenkins)
[ssh-agent] Looking for ssh-agent implementation...
[ssh-agent]   Exec ssh-agent (binary ssh-agent on a remote machine)
Executing shell script inside container [terraform] of pod [gcp-tf-builder-h79rb-h5f3m]
Executing command: "ssh-agent" 
exit
SSH_AUTH_SOCK=/tmp/ssh-2xAa2W04uQV6/agent.20; export SSH_AUTH_SOCK;
SSH_AGENT_PID=21; export SSH_AGENT_PID;
echo Agent pid 21;
SSH_AUTH_SOCK=/tmp/ssh-2xAa2W04uQV6/agent.20
SSH_AGENT_PID=21
Running ssh-add (command line suppressed)
Identity added: /home/jenkins/agent/workspace/demo@tmp/private_key_2729797926.key (user@workstation.local)
[ssh-agent] Started.
[Pipeline] {
[Pipeline] sh
+ ssh-add -L
ssh-rsa REDACTED user@workstation.local
[Pipeline] sh
+ terraform init
[0m[1mInitializing modules...[0m
- module.demo_proj
  Getting source "git::ssh://git@bitbucket.org/company/terraform-module"
[31mError downloading modules: Error loading modules: error downloading 'ssh://git@bitbucket.org/company/deploy-kickstart-project': /usr/bin/git exited with 128: Cloning into '.terraform/modules/e11a22f40c64344133a98e564940d3e4'...
Host key verification failed.
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
[0m[0m
[Pipeline] }
Executing shell script inside container [terraform] of pod [gcp-tf-builder-h79rb-h5f3m]
Executing command: "ssh-agent" "-k" 
exit
unset SSH_AUTH_SOCK;
unset SSH_AGENT_PID;
echo Agent pid 21 killed;
[ssh-agent] Stopped.
</code></pre>

<p>I've triple checked and I am for sure using the correct key pair. I am able to git clone locally from my mac to the repo with no issues. </p>

<p>An important note is that this Jenkins deployment is running within Kubernetes. The Master stays up and uses the Kubernetes plugin to spawn agents. </p>

<p>What does the <code>Host key verification failed.</code> error mean? From my research it can be due to known_hosts not properly being set. Is ssh-agent responsible for that?</p>

<p>Turns out it was an issue with known_hosts not being set. As a workaround we added this to our jenkinsfile</p>

<pre><code>  environment {
    GIT_SSH_COMMAND = "ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no"
  }
</code></pre>
