Github user StephanEwen commented on the issue:
https://github.com/apache/flink/pull/6108
Do you have a Hadoop version older than 2.7?
We are currently attempting to rewrite the Bucketing Sink completely for
better compatibility with S3 and with better support for Parquet / ORC. We were
actually thinking to drop support for file systems that do not support
`truncate()` - so getting this feedback would be good.---
