Flink job with CassandrSink fails with Error writing

I might be wrong, but most likely the issue is caused by netty client version conflict. The error states NoHostAvailableException, however the underlying error is TransportException with Error writing error message. Cassandra s definetely operating well.

There is a kind of similar stackoverflow case - Cassandra - error writing, with a very similar symptoms - a single project running well and AllNodesFailedException with TransportException with Error writing message as a root cause when adding one more. The author was able to solve it by unifying the netty client.

In your case, I'm not sure why there are so many dependencies, so I would try to get rid of all extras and libraries and would just leave Flink (v 1.10.0-scala_2.12) and Flink Cassandra Connector (flink-connector-cassandra_2.12:jar:1.10.0) libraries. They must already include necessary drivers, netty, etc. All other drivers should be skipped (at least for initial iteration to ensure that this solves the issue and it's library conflict).