Hi, I have a Flink application sourcing from a topic in Kafka (400 partitions) and sinking to S3 using bucketingsink and using RocksDb for checkpointing every 2 mins. The Flink app runs with parallelism 400 so that each worker handles a partition. This is using Flink 1.5.2. The Flink cluster uses 10 task managers with 40 slots each.
After running for a few days straight, it encounters a Flink exception:
Org.apache.flink.util.FlinkException: The assigned slot container_1234567_0003_01_000009_1 was removed.
This causes the Flink job to fail. It is odd to me. I am unsure what causes this. Also, during this time, I see some checkpoints stating "checkpoint was declined (tasks not ready)". At this point, the job is unable to recover and fails. Does this happen if a slot or worker is not doing processing for X amount of time? Would I need to increase the Flink config properties for the following when creating the Flink cluster in yarn?
Any help would be greatly appreciated.