Hello!
I try to use lago.ssh for ssh connection to non-host vm in ovirt-system-tests.And I have login/password (not root) for vm, but have not ssh-key. 
I try to use lago.ssh.get_ssh_client() to get connection but there is next code there:
if ssh_key:
  client.connect(
      ip_addr,
      username=username,
      password=password,
      key_filename=ssh_key,
      timeout=ssh_timeout,
      )
  else:
     client.connect(
         ip_addr,
         username='root',
         timeout=ssh_timeout,
     )
     break
But if I can't use key file, client should try to connect using login/password. 
And according this code I have to create empty file for this function and delete it after.
(if ssh key != None but in is not existed file, client.connect )
Is it a bug? Or is there some reasons for implementing this logic?
Sincerely, Valentina Makarova