Python - Kafka：消费者失败

Question

我有一个简单的生产者-消费者设置：1 个生产者（作为线程）和 2 个消费者（作为 2 个进程）。 producer的run方法：

    def run(self):
        producer = KafkaProducer(bootstrap_servers=self.bootstrap_servers, 
                                 api_version=(0, 10))
        while not self.stop_event.is_set():
           self.logger.info("Checking for new changes")
           self.check_for_new_changes(producer)
           self.logger.info("Sleeping for {minutes} 
                          minutes...".format(minutes=self.time_to_sleep / 60))
           time.sleep(self.time_to_sleep)
        producer.close()

基本上它会检查更改，如果发现新更改则发送消息，然后休眠 5 分钟。

运行方法：

def run(self):
    if self.group_id:
        consumer = KafkaConsumer(bootstrap_servers=self.bootstrap_servers,
                                 consumer_timeout_ms=1000,
                                 api_version=(0, 10),
                                 group_id=self.group_id)
    else:
        consumer = KafkaConsumer(bootstrap_servers=self.bootstrap_servers,
                                 consumer_timeout_ms=1000,
                                 api_version=(0, 10))
    consumer.subscribe(['new_change'])
    while not self.stop_event.is_set():
        for msg in consumer:
            self.logger.info("New message:\n{msg}".format(msg=msg))
            self.process_new_change(json.loads(msg.value))
            if self.stop_event.is_set():
                consumer.close()
                return
    consumer.close()

它似乎工作正常，但运行一段时间后，我在协调器日志中收到这些消息：

[2017-12-17 02:06:40,639] INFO [GroupCoordinator 0]: Member kafka-python-1.3.5-f5cdcad3-bc1a-4623-a42b-f5de5e8bded1 in group meta_data_consumer has failed, removing it from the group (kafka.coordinator.group.GroupCoordinator)
[2017-12-17 02:06:40,659] INFO [GroupCoordinator 0]: Preparing to rebalance group meta_data_consumer with old generation 15 (__consumer_offsets-6) (kafka.coordinator.group.GroupCoordinator)
[2017-12-17 02:06:40,659] INFO [GroupCoordinator 0]: Group meta_data_consumer with generation 16 is now empty (__consumer_offsets-6) (kafka.coordinator.group.GroupCoordinator)
[2017-12-17 02:06:41,784] INFO [GroupCoordinator 0]: Member kafka-python-1.3.5-bdea8ce3-922f-4ee1-9959-13341e1730f5 in group failures_consumer has failed, removing it from the group (kafka.coordinator.group.GroupCoordinator)
[2017-12-17 02:06:41,785] INFO [GroupCoordinator 0]: Preparing to rebalance group failures_consumer with old generation 9 (__consumer_offsets-35) (kafka.coordinator.group.GroupCoordinator)
[2017-12-17 02:06:41,785] INFO [GroupCoordinator 0]: Group failures_consumer with generation 10 is now empty (__consumer_offsets-35) (kafka.coordinator.group.GroupCoordinator)

这会杀死我的消费者并且他们停止运行。 我在消费者日志中没有看到任何异常或错误。

什么可能导致他们失败？

Answer 1

我认为您的zookeeper.session.timeout.ms 设置为低于 5 分钟。从 zookeeper 设置中调整超时。看看它是否仍然失败。如果是这样，那么您应该调整 kafka 配置中的超时。 group.max.session.timeout.ms、rebalance.timeout.ms、heartbeat.interval.ms 应相应调整。您的客户端休眠了 5 分钟，在此期间，超过了其中一个超时值，组协调器尝试重新平衡消费者，认为这些消费者已经失败。

来源：Kafka Documentation