A national retailer runs virtual machines at a public cloud provider. Retailer staff install and patch the guest operating systems and the applications, and the provider supplies the infrastructure. Which NIST service model is this?
Select an answer to reveal the explanation.
Short Explanation
Renting the building is not the same as renting a finished office. You are looking at infrastructure as a service, because your staff still patch the guest operating system and the applications. Software as a service would hand you the application and keep that patching.
Full Explanation
NIST service models split who operates which layer. Infrastructure as a service gives the customer compute, storage, and network, and the customer manages the guest operating system and the applications. That is the retailer arrangement: provider infrastructure, retailer staff patching the guests. Software as a service delivers an application the customer uses. The customer does not patch the guest operating system, so the distractor that treats OS patching as software as a service reverses the model. Platform as a service lets the customer deploy an application onto a provider runtime. The customer does not take the guest operating system patch cycle, so controlling that cycle is not platform as a service. Private cloud is a deployment model, meaning the infrastructure is set aside for one organization. It is not a service model, and a virtual machine at a public provider is not defined as a private cloud. Caveat: NIST also expects the five essential characteristics, including on-demand self-service and measured service, before the arrangement is fully a cloud service. The question asked only for the service model. Operational check: write down who patches the guest OS. If it is the retailer, keep the label at infrastructure as a service.