VMware vSphere is licensed on a per-processor basis, without imposing any restrictions on the number of virtual machines, physical cores, or the amount of physical RAM. To install vSphere in a virtual environment, at least one license key should be assigned to each physical processor (CPU).

The VMware vSphere license has a simple license key, which consists of an encrypted string of 25 characters (numbers and letters) that contain information about the acquired vSphere edition or kit, and the number of processors. A license key is not attached to a specific server, meaning that this key can be assigned to multiple vSphere hosts. However, note that the number of physical processors on those hosts should not exceed the number of processors encoded in the license key. Moreover, license keys can be assigned centrally through VMware vCenter Server or directly to individual hosts. There is no significant difference between directly and centrally assigned license keys.

With VMware vCenter Server, you can manage licenses that are assigned to vSphere hosts. VMware vCenter Server assigns a license key, then copies and saves it in the host. Even if the host loses connection with vCenter Server, the license key is kept active on the host, and can be saved there for a long period of time.

As mentioned above, VMware vSphere Platinum Edition combines two components – VMware vSphere and VMware AppDefense. Thus, they are licensed as a single product and have a single license. All VMs running on a properly licensed VMware vSphere Platinum processor can use all vSphere components. However, a single license of vSphere Platinum cannot be used across multiple processors.

VMware vSphere Compute Virtualization Licensing, pricing and packaging