Cloud Concepts is where almost everyone starts the AZ-900, and there is a reason it feels approachable: it is the most vocabulary-driven area of the exam. You are not being asked to build anything or debug a broken deployment. You are being asked to recognise a situation and give it the right name. That is a very learnable skill, and this page is built to help you practise it with real Azure examples rather than abstract definitions.
Why this domain rewards clear labels
At 25–30% of the exam, Cloud Concepts is the smallest of the three AZ-900 areas — but it sets up everything after it. Most questions here describe a scenario in a sentence or two and ask you to pick the term that fits: is this IaaS or PaaS? Public, private or hybrid? High availability or scalability? If the words are crisp in your head, these questions take seconds. If they blur together, four options all look plausible. So the whole game is turning fuzzy definitions into sharp ones, and the fastest way to do that is to pin each term to a concrete Azure service you can picture.
The service models, seen through Azure
The diagram above is the single most useful picture in this domain. It shows the same stack — applications, data, runtime, operating system, virtualisation, storage and networking — under three service models, shaded by who manages each layer. Read it left to right and the pattern jumps out: the more managed the service, the less of the stack is yours.
- IaaS — Azure Virtual Machines. You manage everything from the operating system up. Full control, full responsibility, including OS patching.
- PaaS — Azure App Service. You bring your code and data; Microsoft runs the OS and everything beneath it. You just deploy.
- SaaS — Microsoft 365. A finished product. You sign in and use it; Microsoft manages the entire stack.
That single line — where the shaded boundary sits — quietly answers a surprising number of exam questions, including who applies a security patch and who is responsible when something below the line breaks.
Deployment models: where the resources live
Separate from the service model is the deployment model, which is about location. Public cloud means your resources live in Microsoft’s data centres. Private cloud means they run on infrastructure dedicated to you, often on-premises. Hybrid cloud combines the two, and the exam loves scenarios where regulation forces some data to stay on-site while the team still wants Azure’s management tools. When you see “on-premises and cloud, managed together,” think hybrid — and think of the Azure services that make it real, like Azure Arc for governing outside servers and Azure Stack for running Azure in your own building.
Concepts that describe behaviour
The last cluster of terms describes how a well-designed Azure workload behaves. High availability keeps a service running through failures — the “is it still up?” question, which you design for with Availability Zones. Scalability is the ability to grow, whether by moving to a bigger machine (scaling up, vertical) or adding more machines (scaling out, horizontal). Elasticity is scaling that happens automatically in both directions, and Azure autoscale on an App Service plan is the textbook example: instances appear when CPU climbs and disappear when the rush passes. Keep these three questions apart — is it up, can it grow, does it adjust itself? — and the distractors stop working on you.
Practise the reasoning, not the answer
Work through the seven questions below one at a time, and read each explanation all the way past the correct option. The “Why not the others:” line is where this domain is actually learned, because on exam day the three wrong answers will look just as tidy as the right one. Get comfortable naming Azure situations here, and Cloud Concepts becomes one of the calmest parts of your test.
Updated for AZ-900 (July 2026). The sample questions above are our own work
in the style of the exam — not real exam items. The exam itself is set and marked
by the certification body.