Non-blocking Clos Network Topology - multiple ports to spine ports

I've been researching and learning on how to build vxlan fabrics in datacenters. I think I get the idea of the underlay and overlay so far, but one question remains.

How to configure the interfaces if there are multiple ports connecting to multiple ports in the same spine for the underlay?

Do I create a port-channel? or do I create multiple loopback interfaces with ip address and assign them to each individual physical port?
I can't seem to find a straight answer when googling.