Druid request routing questions

[Felix Hennig]

Hi,

I in my use of Druid so far I have always simply sent all my requests to the Router process. The documentation mentions that the router routes requests to specific brokers based on the data that is accessed. But the documentation also states that the router is optional.

What is the best practice? Should I always use a router? When does it make sense to bypass the router and access brokers directly?

The documentation also mentions that the Router communicates with the Coordinator and Overlord. What is the nature of the API calls between them?

Are there any considerations to be made from a security perspective, regarding which services should be accessible?

Cheers!