Cloud Computing Fundamentals
What this domain tests
Cloud Computing Fundamentals checks whether you can define cloud precisely and classify offerings using the NIST model rather than vendor marketing. Questions typically ask you to distinguish essential characteristics, service models, and deployment models, and to decide whether a scenario is truly cloud.
Core rules
- NIST SP 800-145 defines cloud as a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources that are rapidly provisioned and released with minimal management effort or provider interaction.
- The five essential characteristics are on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service. All five must be present for a service to be cloud under this model.
- Service models: SaaS delivers a provider-managed application; PaaS delivers a platform for consumer-created or acquired applications using provider-supported languages and tools; IaaS delivers processing, storage, and network resources that the consumer can provision and control.
- Deployment models: public, private, hybrid, and community. Private cloud is defined by dedicated use and control, not by physical location; it can be operated on-premises or by a third party.
Worked example
A hospital chain runs its own VMware cluster behind a firewall with a self-service portal, pooled capacity for affiliated clinics, measured chargeback, and rapid provisioning. Classification: a private cloud, or a community cloud if the affiliates share common concerns and governance. It is not public cloud merely because it uses virtualization. If the portal were removed and capacity were not measured, the environment would be virtualization rather than cloud under the NIST model.
Traps that cost marks
- Treating private cloud as automatically on-premises. Outsourced private cloud exists.
- Confusing elasticity with scalability. Elasticity automatically matches capacity to current demand; scalability is the ability to handle growth.
- Assuming SaaS means the customer manages the operating system. In SaaS the provider manages the application stack.
- Forgetting that multi-tenancy is resource pooling, not proof of public cloud. A private cloud can also be multi-tenant within one organization.