The pay-per-use monitor mechanism measures cloud-based IT resource usage based on parameters that are predefined in pricing plans and generates usage logs for fee calculations.
Typical monitoring variables are:
- request/response message quantities
- transmitted data volume
- bandwidth consumption
The data collected by the pay-for-use monitor is processed by a billing system that calculates payment fees.
Figure 1 shows a pay-per-use monitor implemented as a resource agent that is used to determine the usage period of a virtual server.
Figure 1 - A cloud consumer requests the creation of a new instance of a cloud service (1). The IT resource is instantiated and the pay-per-use monitor receives a "start” event notification from the resource software (2). The pay-per-use monitor stores the value timestamp in the log database (3). The cloud consumer later requests that the cloud service instance be stopped (4). The pay-per-use monitor receives a "stop” event notification from the resource software (5) and stores the value timestamp in the log database (6).
Figure 2 illustrates a service usage monitor designed as a monitoring agent that transparently intercepts and analyzes runtime communication with a cloud service.
Figure 2 - A cloud service consumer send a request message to the cloud service (1). The pay-per-use monitor intercepts the message (2) and The service agent forwards the messages to the cloud service (3a), and stores the usage information in accordance with its monitoring metrics (3b). The cloud service forwards the messages back to the cloud consumer to provide the requested service (4).