1. A method comprising: receiving, by a virtual appliance monitor executing in a network cloud system, appliance state information representing an execution state of a virtual appliance of a set of virtual appliances instantiated in the network cloud system that the virtual appliance monitor is to monitor, wherein the virtual appliance monitor is instantiated by a cloud management server device managing the network cloud system; managing, by the virtual appliance monitor, the set of virtual appliances in view of the receiving appliance state information; determining that a first subscription period for the virtual appliance monitor has expired, wherein the first subscription period comprises a first determined time period covering use of the virtual appliance monitor, the first determined time period having a first predetermined and defined expiration time to cause the cloud management server device to terminate execution of the virtual appliance monitor; responsive to determining that the first subscription period expired, determining that a second subscription period for the set of virtual appliances has expired, wherein the second subscription period comprises a second determined time period covering use of the set of virtual appliances, the second determined time period having a second predetermined and defined expiration time to cause the cloud management server device to terminate execution of the set of virtual appliances; and responsive to determining that both of the first subscription period and the second subscription period have expired, terminating, by the cloud management server device, the virtual appliance monitor and the set of virtual appliances monitored by the virtual appliance monitor.