Study Azure AZ-900 Cloud Models: key concepts, common traps, and exam decision cues.
AZ-900 begins by testing whether you understand what cloud actually changes. Microsoft is looking for the big model shifts: public versus private versus hybrid, consumption-based spending, shared responsibility, and the idea that some services hide more infrastructure management than others.
Consumption-based model: Cloud spending model where cost aligns more closely with actual use instead of only with long upfront ownership.
Serverless: Cloud execution model where the provider manages more of the underlying infrastructure and capacity logic for you.
| Model | Best mental label | Strongest exam cue |
|---|---|---|
| Public cloud | provider-owned shared cloud platform delivered over the internet | speed, elasticity, and provider-managed services |
| Private cloud | cloud-like environment dedicated to one organization | maximum organizational control or special isolation needs |
| Hybrid cloud | combination of on-premises/private and public cloud environments | some workloads stay local while others move to Azure |
AZ-900 likes to ask which model fits the requirement. If the company needs to keep part of the workload on-premises while also using Azure services, hybrid is often the real lane.
Microsoft uses the shared responsibility model to test whether you understand that moving to cloud does not remove all customer duties. Microsoft secures the underlying platform. The customer still owns data, identities, and many configuration choices.
| Microsoft handles more of… | Customer still handles… |
|---|---|
| physical datacenters, host hardware, and core cloud platform | data, identities, access choices, and workload configuration |
| service availability foundations | whether the deployed solution is governed and secured correctly |
| platform operations for managed services | what users and apps are allowed to do |
The core pricing idea is simple:
AZ-900 usually wants the concept, not a finance-specialist calculation.
| If the question emphasizes… | Strongest first reading |
|---|---|
| large up-front ownership | CapEx-style purchasing |
| ongoing usage-driven billing | OpEx-style cloud spending |
| spending that changes with demand | consumption-based model |
Serverless is still a cloud-concepts topic because it highlights the model shift:
That makes serverless a cloud-concepts topic before it becomes a product-choice topic. AZ-900 wants you to recognize the management shift, not engineer a serverless platform.
| If two answers both sound right… | Choose based on… |
|---|---|
| hybrid cloud versus private cloud | whether public cloud is still part of the design |
| consumption model versus shared responsibility | whether the stem is about spending or duties |
| serverless versus PaaS | whether the question is about hiding even more infrastructure work |