I suggest a improvement to auto-reconnect zk nodes, when all socket.getaddrinfo failed. (auto-retry when all zookeeper nodes lost connection)

[alhambraGod]

in kazoo/protocol/connection.py https://github.com/python-zk/kazoo/blob/master/kazoo/protocol/connection.py

def _connect_loop(self, retry):
    # Iterate through the hosts a full cycle before starting over
    status = None
    host_ports = self._expand_client_hosts()

    # Check for an empty hostlist, indicating none resolved
    if len(host_ports) == 0:
        return STOP_CONNECTING

    for host, port in host_ports:
        if self.client._stopped.is_set():
            status = STOP_CONNECTING
            break
        status = self._connect_attempt(host, port, retry)
        if status is STOP_CONNECTING:
            break
    ...

in retry.py https://github.com/python-zk/kazoo/blob/master/kazoo/retry.py

class KazooRetry:
    ...
    def __call__(self, func, *args, **kwargs):
        self.reset()

        while True:
            try:
                if self.deadline is not None and self._cur_stoptime is None:
                    self._cur_stoptime = time.time() + self.deadline
                    return func(*args, **kwargs)
            except ConnectionClosedError:
                raise
            except self.retry_exceptions:
                # Note: max_tries == -1 means infinite tries.
                if self._attempts == self.max_tries:
                    raise RetryFailedError("Too many retry attempts")
                ...
    ...

when all sockets failed to reconnect, it will just retry for once and then return STOP_CONNECTING.

so I suggest if len(host_ports) == 0 (all zookeeper server can not be connected at runtime), a RETRY_EXCEPTIONS should be thrown, eg.
in connection.py   def _connect_loop(self, retry):
if len(host_ports) == 0:
    raise ForceRetryError()
          not just return STOP_CONNECTING

then, except of self.retry_exceptions in retry.py will be triggered to force class KazooRetry keep retrying.
when zookeeper server return to normal, our services will reconnect to zookeeper server.

thanks