Fundamental principles and concepts of cloud computing
Domain 1 covers fundamental cloud principles and how the exam expects you to reason about accountability. You must distinguish service and deployment models, recognize the ISO/NIST vocabulary for cloud computing, and apply the shared responsibility model to concrete roles.
Core rules and concepts
- Essential characteristics include on-demand self-service, broad network access, resource pooling, rapid elasticity and measured service.
- Service models: IaaS supplies virtual compute, storage and network; PaaS supplies a managed application platform; SaaS supplies a completed application. Control of the OS, runtime, application and data shifts accordingly.
- Deployment models: public, private, community and hybrid. They describe ownership and exposure, not whether the service is secure.
- Shared responsibility splits duties; it never eliminates customer accountability for data, identities, configuration and use.
- Multi-tenancy, elasticity, API-driven administration and jurisdiction create both scale benefits and new exposure.
Worked example
A payroll SaaS is used by HR. The provider patches the application and operates the data centre. The customer still decides which HR users get access, enforces MFA, classifies payroll data, configures retention and reviews provider assurance. If an API key leaks, the customer must revoke it and investigate its own use; the provider handles platform containment.
Traps
Do not say the provider is responsible for 'everything' in SaaS, or that the customer always patches the guest OS in IaaS. Do not treat private cloud as automatically compliant. Do not confuse deployment model with service model.