Does clustering Tyk gateway nodes always require MDCB?

Hi,
I want to configure Tyk cluster in my local Ubuntu servers. I read the documentation about sharding, if I want to configure multiple nodes of Tyk in my 3 local servers, how can I make sure then will communicate each other, I got little bit confused in this topic. Please help.

Thank You,
Shiva

MDCB is if you want to run across multiple data centers, If you have a single Tyk environment (e.g. production), and that environment consists of 3 servers, then you just need to install Tyk on all three servers and ensure they are all using the same redis DB.