Thanks for your reply. But I still can not figure out why the value of offset is frequently reset. I am sure, the groupId is unique for my kafka cluster.
I find that some messages lost in flume pipeline. But I don’t know the reason. Please do me a favour.
What that means is that the KafkaSource is trying to read messages from the last time it was running (or at least the last time some client used kafka with the same groupId) but they have been already deleted by Kafka so is working you that there are messages that have been missed.
Even if is the first time you use the KafkaSource, maybe somebody used a Kafka consumer with the same groupId long ago. It's better if you make up your own groupId so you don't have strange conflicts.