One of the benefits of the hypervisor is the ability to install multiple operating systems on one system. If your subscription is a Mac mini with quad core i7 CPU, you can run multiple virtual machines with various operating systems on the server.
In the past we installed the VMware ESXi hypervisor and created a Linux virtual machine by request. Due to the complex nature of installing Linux and the many variations available, we now offer the base VMware ESXi installation with no virtual machines included. Customers may install virtual machines on their own.
We don’t do any initial operating system customization. When you initially order a server with macOS on it, it's macOS on the bare metal Mac just as if you’d bought it at a store.