Cloud Concepts is the foundational domain of the AZ-900 exam, designed to introduce you to the core ideas behind cloud computing. In plain English, this domain covers what the cloud is, how it works, and why businesses are moving to it. You'll learn about the different cloud service models (IaaS, PaaS, SaaS) and deployment models (public, private, hybrid). Think of it like understanding the difference between owning a car (on-premises), leasing one (IaaS), taking a taxi (PaaS), or riding a bus (SaaS). Each has trade-offs in control, cost, and maintenance.
Why is this important for real-world IT work? Because cloud computing is now the default for most organizations. Whether you're a system administrator, developer, or security analyst, you'll need to understand concepts like scalability (adding resources when demand spikes), elasticity (automatically scaling up and down), and high availability (keeping services running even if a server fails). For example, an e-commerce site uses cloud elasticity to handle Black Friday traffic without crashing. Without these concepts, you can't design cost-effective, resilient systems.
The exam tests your ability to define and compare these concepts, not to implement them. You'll see questions like 'Which cloud model gives you the most control?' (IaaS) or 'What is a benefit of public cloud?' (pay-as-you-go pricing). You need to know the differences between CapEx (buying hardware upfront) and OpEx (paying for what you use), and understand that the cloud shifts costs from CapEx to OpEx. Also, know the shared responsibility model: the cloud provider secures the infrastructure, but you secure your data and applications.
To study, start by memorizing the definitions and examples for each model and concept. Use mnemonics: IaaS = 'Infrastructure as a Service' = you manage the OS and apps; PaaS = 'Platform as a Service' = you only manage apps; SaaS = 'Software as a Service' = you just use it. Then, practice with sample questions to see how these concepts are applied in scenarios. Focus on why a company would choose one model over another. For instance, a startup might prefer PaaS to avoid managing servers. Finally, understand the trade-offs in cost, control, and responsibility. This domain is the easiest to score high on if you master the vocabulary.
Cloud Concepts covers the fundamental principles of cloud computing, including service models (IaaS, PaaS, SaaS), deployment models (public, private, hybrid), and key concepts like scalability, elasticity, high availability, and the shared responsibility model.
Define and compare IaaS, PaaS, and SaaS with examples
Describe public, private, and hybrid cloud deployment models
Explain the shared responsibility model and who secures what
Differentiate between CapEx and OpEx and how cloud shifts costs
Identify benefits of cloud computing like scalability, elasticity, and high availability
Understand consumption-based pricing and its advantages
Common exam traps
Where candidates lose marks on Describe cloud concepts
⚠Confusing IaaS with PaaS: IaaS gives you control over the OS and apps; PaaS only over apps
⚠Thinking public cloud is always cheaper than on-premises (it depends on workload)
⚠Mixing up scalability (adding resources) with elasticity (automatic scaling)
⚠Assuming the cloud provider is responsible for all security (shared responsibility model)
AZ-900 Describe cloud concepts — Practice Questions
A startup wants to deploy a web application that experiences unpredictable traffic spikes. They need to scale resources automatically without manual intervention. Which benefit of cloud computing directly addresses this requirement?
A retail company runs its e-commerce platform on a public cloud. During a major sale event, they want to ensure that the application remains accessible even if an entire data center fails. Which cloud computing concept does this describe?
A financial services company is evaluating a public cloud provider. They are concerned about the shared responsibility model for security. The company must ensure that their customer data is encrypted at rest and in transit. Under the shared responsibility model, which security control is the cloud provider typically responsible for?
A multinational corporation wants to reduce its carbon footprint by shifting workloads to the cloud. They want to understand how using a cloud provider's shared infrastructure contributes to sustainability. Which cloud computing concept is most directly related to this environmental benefit?
A small business wants to move its accounting software to the cloud to avoid purchasing and maintaining physical servers. Which cloud service model would provide the accounting application as a ready-to-use service over the internet?
A hospital is subject to strict data residency laws that require patient data to remain within the country's borders. They are considering using a public cloud provider. Which cloud deployment model would best meet this compliance requirement?
A small business wants to run its accounting application without managing the underlying operating systems or hardware. The application is accessed through a web browser. Which cloud service model is being used?
A financial services company processes sensitive customer data and must strictly control the physical location of the servers. They want to use cloud computing but with dedicated hardware that is not shared with other customers. Which cloud deployment model should they choose?
A company runs a web application that experiences sudden spikes in traffic during promotional events. They want to automatically add more virtual machines during high demand and remove them when traffic subsides, paying only for the resources used. Which cloud computing benefit does this scenario describe?
A company is evaluating moving its on-premises applications to the cloud. The IT manager wants to avoid upfront hardware costs and instead pay for resources on a monthly basis based on usage. Which cloud characteristic enables this financial model?
A company is considering moving its IT infrastructure to the cloud. The CFO wants to understand the financial impact: instead of purchasing servers and paying for maintenance, the company will pay a monthly fee based on usage. This shift represents moving from which type of expenditure to which?
A company wants to increase the number of virtual machines it uses during peak hours and decrease them during off-peak hours without manual intervention. Which characteristic of cloud computing does this represent?
A startup wants to use a cloud-based email service without installing any software on their own computers. They access the service through a web browser and the provider manages all updates and maintenance. Which cloud service model does this represent?
A bank needs to keep some sensitive customer data on-premises due to regulatory requirements, but wants to use cloud services for less sensitive workloads. Which cloud deployment model should they adopt?
A company is moving from an on-premises data center to Azure. Instead of paying a large upfront cost for servers, they will pay a monthly subscription fee based on usage. This represents a shift from which type of expenditure to which?
A startup wants to quickly deploy a web application without worrying about server maintenance. They only want to focus on writing code and deploying it. Which cloud service model best fits this requirement?
A company is considering moving its on-premises workloads to the cloud. They want to reduce their carbon footprint by using a cloud provider that uses renewable energy. Which cloud computing benefit is most directly related to this goal?
A company wants to ensure that its cloud resources are available even if a major disaster occurs in one region. They plan to deploy resources in two different geographic locations. Which cloud computing characteristic does this scenario primarily address?
A company wants to pay only for the compute resources they actually use, with no upfront costs. They can scale up or down based on demand. Which cloud pricing model does this describe?
A company runs a seasonal e-commerce application. During holidays, traffic increases tenfold, but the company does not want to over-provision resources for the rest of the year. They want to add or remove server capacity automatically based on real-time demand and pay only for what they use. Which cloud computing characteristic does this scenario describe?
A startup is building a mobile app backend and wants to use cloud services. They want to focus entirely on writing code and deploying features without worrying about server maintenance, operating system patches, or scaling infrastructure. Which cloud service model best fits this requirement?
A hospital stores sensitive patient data in the cloud. They want to ensure that data remains secure and that the cloud provider has implemented strict physical security controls, such as biometric access and 24/7 surveillance at datacenters. Which aspect of the shared responsibility model does this describe?
A company wants to reduce its carbon footprint by using a cloud provider that invests in renewable energy. They want to ensure that their workloads in Azure run in datacenters that are among the most energy-efficient. Which Azure benefit is most directly related to this goal?
A company is moving from an on-premises data center to the cloud. Previously, they paid a large upfront sum for hardware and then annual maintenance fees. Now they pay a monthly subscription based on actual usage of compute and storage. This shift represents moving from which type of expenditure to which?
A company is moving from an on-premises data center to the cloud. Previously, they paid a large upfront sum for servers and storage, plus annual maintenance fees. Now they pay a monthly subscription based on the amount of compute and storage they actually use. This shift represents moving from which type of expenditure to which?
A startup wants to run a web application without purchasing or managing any servers. They only want to upload their code and let the cloud provider handle everything from the runtime to scaling. Which cloud service model best fits this requirement?
A hospital stores patient data in the cloud. They are concerned about physical security at the datacenter. Which aspect of the shared responsibility model describes the cloud provider's obligation to secure the physical infrastructure?
A company runs a seasonal e-commerce application. During the holiday season, demand spikes significantly, but the company does not want to pay for idle resources the rest of the year. They want the cloud to automatically add or remove compute resources based on real-time demand. Which cloud computing characteristic does this scenario best describe?
A company is moving its on-premises data center to the cloud. Previously, they purchased servers and paid for maintenance. Now they pay a monthly subscription for compute and storage based on actual usage. This is an example of shifting from capital expenditure (CapEx) to which type of expenditure?
A hospital stores patient health records in the cloud. They are responsible for encrypting the data before storing it, while the cloud provider is responsible for securing the physical datacenter. Which cloud model is being described?
More Describe cloud concepts questions available in the full practice test.