The article describes a method of securely seeding private key data to newly provisioned servers. It's a bit of bootstrapping problem, and not something a PKI can solve.

You usually need some form of trusted communication with a new server until you can give it its real identity, in the form of host names and cryptographic keys. In an enterprise environment this can usually be done with some sort of isolated management or provisioning vlan. In a cloud environment, I've seen all sorts of more or less hacky solutions but since it depends a lot on specific details of your networks and APIs, bespoke solutions are fine.