To use SSH public key authentication, you should make sure that your Jenkins slave can log into your monitored host by public key authentication.

To enable public key authentication, execute following commands on your Jenkins slave:

    # If you don't have a SSH key pair, create one. Ignore this command otherwise.
    ssh-keygen

    # copy your public key to monitored host:
    ssh-copy-id <username>@<monitored_host>