Metering and Chargeback Design
There are multiple models employed by service providers to meter and invoice end consumers. For instance, both the vCenter Server design options discussed in this paper have relied upon a dedicated host hardware model. While other physical resources might be shared, such as network switches or array-based storage, the ESXi host server resources are only being consumed by a single tenant. Where this is the case, the service provider might invoice their customers based on the host hardware being consumed, rather than actual CPU and memory resource being utilized, because those metrics become largely irrelevant, other than perhaps power consumption. Pricing and packaging models, like those illustrated in the following figure, are commonplace among many of the service providers who provide both dedicated and shared vCenter Server service offerings.
Figure 19. Dedicated vCenter Server Example Pricing and Packaging
Disclaimer: The pricing and packing shown here are fictitious, and not based on any service providers P&P model.
However, there is also an alternate means of billing customers, which might provide a more agile or deterministic approach to pricing and packaging. VMware vRealize Business™ for Cloud is an end-to-end cost reporting solution for virtual environments that enables accurate cost measurement, analysis, and reporting of virtual machines using vSphere. Virtual machine resource consumption data is collected from vCenter Server, providing the most complete and accurate tabulation of resource costs. Integration with vCloud Director and NSX also enables automated chargeback for private and public cloud environments.
The key features required when designing a metering solution that provides the most complete and accurate tabulation of resource costs include the following:
• Map IT cost to business units, cost centers, or external consumers, thereby enabling a better understanding of how much resources cost and what can be done to optimize resource utilization.
• Support for policy-driven accountability for self-service environments so that business owners can pay as they go for cloud resources.
• Support for allocation-based costing, utilization-based costing, or a combination of both to fit a service provider’s unique costing policies.
• Allow consumers to baseline costs, have fixed costs, one-time costs, multiple rate factors, and over usage fees to model true costs.
• Meter all resources managed in vCenter Server, including network traffic, public IP addresses, and other services such as DHCP, NAT, and firewalling.
• Provide detailed reports generated for tenants to facilitate decision making and planning.
• Allow service providers to see the actual cost of the cloud infrastructure required to support business services.
• Verify that cost models can be customized to different tenants’ processes and policies.
