title: Kafka multiple producers to specific same partition
body: <p>Using spring kafka template, I have 2 different producers that send different messages with the same key to a topic always in the same form:</p>
  
  <p><strong>Producer 1:</strong> Sends Key: 1 message: abc partition 0</p>
  
  <p><strong>Producer 2:</strong> Sends Key: 2 message: def</p>
  
  <p>I have 3 partitions and all messages are sent to the same according to the message key.</p>
  
  <p>Now, I need to make sure, that according to some properties, specific messages will go to specific partitions to be able to manage some priority in the system. </p>
  
  <p>Thing is Producer 2 doesn't have a way to know which partition the Producer 1 selected.</p>
  
  <p>Kafka assures that messages from different producers sent to with the same key will go to the same partition. But when assigning the partition from the producer 1, producer 2 sends the message with the same key to a different partition.</p>
  
  <p>I've seen information about this, but none with the producer selecting the partition that will use.</p>
  
  <p>Shouldn't kafka keep assigning the same partition to the message even though  producer ones picks the partition it will use?</p>