You need to add the batlab to the known hosts for this to work.  a la:

```python
        key = paramiko.RSAKey(filename=rc.ssh_key_file)
        client = paramiko.SSHClient()
        client.load_system_host_keys()
        client.get_host_keys().add(BATLAB_SUBMIT_HOSTNAME, 'ssh-rsa', key)
```