Controlling usage of virtual disks in a data-processing center hosting a set of virtual machines is described where each virtual disk comprises a set of software artifacts. A corresponding method comprises detecting a request of adding a new virtual disk comprising a set of new software artifacts to a selected one of the virtual machines, determining composition information of the new virtual disk, which includes an indication of the new software artifacts, retrieving an indication of usage entitlements of the new software artifacts in the data-processing center, enabling or preventing the attachment of the new virtual disk to the selected virtual machine according to a comparison between the composition information and the usage entitlements, attaching the new virtual disk to the selected virtual machine in response to the enabling thereof, and updating the usage entitlements in response to the attachment of the new virtual disk.