I used a single physical server. The first ESXi server is installed on the top of the server. I call the ESXi hypervisor MasterESXi. This MasterESXi then hosts multiple VMs, some of which are used to provide infrastructure services, such as DNS, Active Directory (AD) services, or iSCSI storage, to the lab. Other VMs are used as nested ESXi hypervisors. Let's take a look at the overall architecture:

Let's now take a look at the different components of the lab.