How do I use SSH in a Jenkins pipeline?

I had a similar issue. I did not use the label 'master', and I identified that the file transfer works across slaves when I do it like this:

Step 1 - create SSH keys in a remote host server, include the key to authorized_keys

Step 2 - Create credential using SSH keys in Jenkins, use the private key from the remote host

Use the SSH agent plugin:

stage ('Deploy') {    steps{        sshagent(credentials : ['use-the-id-from-credential-generated-by-jenkins']) {            sh 'ssh -o StrictHostKeyChecking=no user@hostname.com uptime'            sh 'ssh -v user@hostname.com'            sh 'scp ./source/filename user@hostname.com:/remotehost/target'        }    }}

Use the SSH agent plugin:

• SSH Agent Plugin
• SSH Agent Plugin

When using this plugin you can use the global credentials.

To add a remote host to known hosts and hopefully cope with your error try to manually ssh from the Jenkins host to the target host as the Jenkins user.

Get on the host where Jenkins is installed. Type

sudo su jenkins

Now use ssh or scp like

ssh username@server

You should be prompted like this:

The authenticity of host 'server (ip)' can't be established. ECDSA key fingerprint is SHA256:some-weird-string. Are you sure you want to continue connecting (yes/no)?

Type yes. The server will be permanently added as a known host. Don't even bother passing a password, just Ctrl + C and try running a Jenkins job.