[jira] [Created] (FLINK-17327) Kafka unavailability could cause Flink TM shutdown

["Jun Qin (Jira)" <ji...@apache.org>]

Jun Qin created FLINK-17327:
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             Summary: Kafka unavailability could cause Flink TM shutdown
                 Key: FLINK-17327
                 URL: https://issues.apache.org/jira/browse/FLINK-17327
             Project: Flink
          Issue Type: Bug
    Affects Versions: 1.10.0
            Reporter: Jun Qin


Steps to reproduce:
 # Start a Flink 1.10 standalone cluster
 # Run a Flink job which reads from one Kafka topic and writes to another topic, with exactly-once checkpointing enabled
 # Stop all Kafka Brokers after a few successful checkpoints

When Kafka brokers are down:
 # {{org.apache.kafka.clients.NetworkClient}} reported connection to broker could not be established
 # Then, Flink could not complete snapshot due to {{Timeout expired while initializing transactional state in 60000ms}}
 # After several snapshot failures, Flink reported {{Too many ongoing snapshots. Increase kafka producers pool size or decrease number of concurrent checkpoints.}}
 # Eventually, Flink tried to cancel the task which did not succeed within 3 min
 # Then {{Fatal error occurred while executing the TaskManager. Shutting it down...}}

I will attach the logs to show the details.  Worth to note that if there would be no consumer but producer only in the task, the behavior is different:
 # {{org.apache.kafka.clients.NetworkClient}} reported connection to broker could not be established
 # after {{delivery.timeout.ms}} (2min by default), producer reports: {{FlinkKafkaException: Failed to send data to Kafka: Expiring 4 record(s) for output-topic-0:120001 ms has passed since batch creation}}
 # Flink tried to cancel the upstream tasks and created a new producer
 # The new producer obviously reported connectivity issue to brokers
 # This continues till Kafka brokers are back. 
 # Flink reported {{Too many ongoing snapshots. Increase kafka producers pool size or decrease number of concurrent checkpoints.}}
 # Flink cancelled the tasks and restarted them
 # The job continues, and new checkpoint succeeded. 
 # TM runs all the time in this scenario

I set Kafka transaction time out to 1 hour just to avoid transaction timeout. 

To get a producer only task, I called {{env.disableOperatorChaining();}} in the second scenario. 

 

 

 



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