Multi-cluster bare-metal server - Advice?



I come to you because I have a question. Currently, I have a cluster of virtual machines running on a KVM. This one is composed of:

3 masters
3 workers

Now I would like to do multi-cluster with federation 2, but is it really possible? I can’t find many well explained tutorials talking about this theme unless it’s on the Cloud.

Do you have any links or advice?