'Check server connectivity
:param ip_address: server to test against
:param username: server\'s ssh username
:param private_key: server\'s ssh private key to be used
:param should_connect: True/False indicates positive/negative test
positive - attempt ping and ssh
negative - attempt ping and fail if succeed
:param mtu: network MTU to use for connectivity validation
:raises: AssertError if the result of the connectivity check does
not match the value of the should_connect param'

def check_vm_connectivity(self, ip_address, username=None, private_key=None, should_connect=True, mtu=None):

    if should_connect:
        msg = ('Timed    out    waiting    for    %s    to    become    reachable' % ip_address)
    else:
        msg = ('ip    address    %s    is    reachable' % ip_address)
    self.assertTrue(self.ping_ip_address(ip_address, should_succeed=should_connect, mtu=mtu), msg=msg)
    if should_connect:
        self.get_remote_client(ip_address, username, private_key)
