How to produce messages to selected partition using kafka-console-producer?

Question

According to the Kafka documentation:

The producer is responsible for choosing which message to assign to which partition within the topic.

Answer 1

Here is your starting point:
partitioner.class setting in your Properties instance. In Kafka, the default implementation is kafka.producer.DefaultPartitioner.

The goal of that setting is:

The partitioner class for partitioning messages amongst sub-topics. The default partitioner is based on the hash of the key.

This means that if you want to change the behaviour of the default partitioner , then you need to create your own implementation of kafka.producer.Partitioner interface.

I would suggest to be really careful when creating your own strategy and really, test it a lot and monitor your topics and their partitions.