In vSphere 6.5, the License Service is part of the Platform Services Controller. The License Service delivers centralized license management and reporting functionality to vSphere and to products that integrate with vSphere.
You can use the License Service with newly installed vSphere 6.0 and later environments. You can also use the License Service with environments that are upgraded from vSphere 5.x to vSphere 6.0 and later. For details about upgrading the license management in vCenter Server 5.x to the License Service in vSphere 6.0 and later, see the vSphere Upgrade guide.
The License Service provides an inventory of licenses in the vSphere environment, and manages the license assignments for ESXi hosts, vCenter Server systems, and clusters with enabled vSAN. The License Service also manages the license assignments for products that integrate with vSphere, such as vRealize Operations Manager, and VMware Site Recovery Manager.
If your vSphere environment has several Platform Services Controllers that are joined through one vCenter Single Sign-on domain, the licensing inventory is replicated across all Platform Services Controllers. This way, the licensing data for each asset and all available licenses are replicated across all the Platform Services Controllers. Each individual Platform Services Controller contains a copy of that data and licenses for all the Platform Services Controllers.
For example, suppose that your environment consists of two Platform Services Controllers that are connected to four vCenter Server systems each, and every vCenter Server system has 10 hosts connected to it. The License Service stores information about the license assignments and uses for all eight vCenter Server systems, and the 80 hosts that are connected to those systems. The License Service also lets you manage the licensing for all eight vCenter Server systems and the 80 hosts that are connected to them through the vSphere Web Client.