| 摘要 |
In a data processing centre hosting a set of virtual machines, virtual disks each comprise a set of software artefacts, e.g. application programs or media content. A request (A1) is detected for adding a new virtual disk, comprising a set of new software artefacts, to one of the virtual machines. Composition information of the new disk is determined (A2 A4), comprising an indication of the new software artefacts, e.g. from a composition library or from a descriptor on the disk. An indication of usage entitlements is retrieved (A5) for the artefacts, e.g. a licensed number of copies of an application program. Attachment of the new disk to the selected virtual machine is enabled or prevented (A6) according to a comparison between the composition information of the new disk and the usage entitlements of the new artefacts. The new virtual disk is attached (A7 A12) to the virtual machine in response to the enabling thereof and the usage entitlements of the new software artefacts are updated (A13) in response to said attachment. An old virtual disk comprising old software artefacts may be removed from a virtual machine by detaching it and updating usage entitlements accordingly (A15 A20). |
