What is going to happen for query/indexing requests sent to master node

Elastic Stack Elasticsearch
1

We have an elastic-search cluster with 3 data nodes and 3 master nodes.
When using it, all traffic(query+indexing) are sent to master nodes in round robin right now. After reading docs, I believe we should change it to sent to data nodes instead. Is that right?

Also, what is going to happen for those requests that are sent to master node? Is this force master nodes to be a "coordinating node"? or it will just redirect to other data nodes?

2

Yes, that is generally best practice.

It will act as coordinating node for that request.

3

Thanks for the clarification @Christian_Dahlqvist

If we decide to add coordinating nodes due to traffic issue, does it make sense to send requests to both data node and coordinating nodes or it is better to send requests to coordinating nodes only?