Document prerequisites for deploying bare metal clusters with BMC. 

Which ports to open for bare metal clusters?

Some info here: https://docs.openshift.com/container-platform/4.13/installing/installing_aws/installing-aws-expanding-a-cluster-with-on-premise-bare-metal-nodes.html

"I cannot find what ports to have open for a BareMetal managed cluster install, I know I need 443/6443 in general but cannot find in our documentation what else is needed, pretty much the whole deploy a BareMetal cluster seems to be lacking some information or I just cannot seem to find it"

"We have 6138 / 5050 and a couple of other ports open, and what we see is that the bootstrapped BM server is trying to connect back to the hub (ACM) on 5050, but there are no node ports or routes for that to happen, here is the link to the case https://access.redhat.com/support/cases/#/case/03588408"