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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