[jira] [Created] (FLINK-17355) Exactly once kafka checkpointing sensitive to single node failures

["Teng Fei Liao (Jira)" <ji...@apache.org>]

Teng Fei Liao created FLINK-17355:
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             Summary: Exactly once kafka checkpointing sensitive to single node failures
                 Key: FLINK-17355
                 URL: https://issues.apache.org/jira/browse/FLINK-17355
             Project: Flink
          Issue Type: Bug
          Components: Connectors / Kafka
    Affects Versions: 1.10.0
            Reporter: Teng Fei Liao


With exactly one semantics, when checkpointing, FlinkKafkaProducer creates a new KafkaProducer for each checkpoint. KafkaProducer#initTransactions can timeout if a kafka node becomes unavailable, even in the case of multiple brokers and in-sync replicas (see [https://stackoverflow.com/questions/55955379/enabling-exactly-once-causes-streams-shutdown-due-to-timeout-while-initializing]).

In non-flink cases, this might be fine since I imagine a KafkaProducer is not created very often. With flink however, this is called per checkpoint which means practically an HA kafka cluster isn't actually HA. This makes rolling a kafka node particularly painful even in intentional cases such as config changes or upgrades.

 

In our specific setup, these are our settings:

5 kafka nodes

Per topic, we have a replication factor = 3 and in-sync replicas = 2 and partitions = 3



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