The docs don't seem to cover on-prem deployments, but if you take a peek under the metaflow-tools repo where the terraform templates reside in, there are also Helm charts available for deploying to on-prem:
https://github.com/outerbounds/metaflow-tools/tree/master/k8s/helm/metaflow
The top level readme still labels the helm charts as alpha, and I've been tweaking some bits with them this week, but it should at the very least serve as a good starting point 🙂
@average-beach-28850 can probably fill in more details if I'm missing some obvious docs for on-prem deployements