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Free sample question, answered and explained below. The AZ-900 Microsoft Azure Fundamentals Exam practice bank has 688 more like it. Try 10 free: instant score, no account.
An organization is migrating several enterprise workloads to Microsoft Azure using a mix of Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS) offerings. The chief information security officer (CISO) requires a clear division of operational tasks to ensure compliance and security standards are maintained.
Which responsibility always remains solely with the customer across all cloud deployment models?
Operating system (OS) management involves installing, configuring, updating, and patching the system software that sits directly above the virtualization layer, as well as maintaining host-level antimalware and firewall configurations.
Operating system maintenance does not remain the customer's responsibility across all cloud deployment models. In an Infrastructure as a Service (IaaS) model (such as Azure Virtual Machines), the customer manages and patches the guest OS. However, in Platform as a Service (PaaS) (such as Azure App Service or Azure SQL Database) and Software as a Service (SaaS) environments (such as Microsoft 365), Microsoft assumes full responsibility for patching, updating, and securing the underlying operating systems.
The scenario focused strictly on an Infrastructure as a Service (IaaS) implementation where virtual machines require administrative oversight for security updates.
Confusing IaaS OS maintenance obligations with universal cloud responsibilities is a common misconception among professionals transitioning to managed PaaS and SaaS services.
In cloud computing, the shared responsibility model defines which security, operational, and maintenance tasks are handled by the cloud provider (Microsoft Azure) and which tasks belong to the customer. While responsibilities for physical infrastructure, operating systems, and middleware shift depending on whether a service is categorized as IaaS, PaaS, or SaaS, certain foundational assets are universally owned by the customer.
Across all cloud deployment models—from raw compute infrastructure to turnkey SaaS applications—the classification, protection, and governance of data and the administration of user identities and access privileges remain exclusively with the customer. Microsoft provides built-in tools such as Azure Role-Based Access Control (Azure RBAC), Microsoft Entra ID, and data encryption options, but configuring these controls and defining access policies is strictly an organization-level obligation.
Recognizing that data and identity governance never transfer to the cloud provider prevents critical compliance gaps. It ensures security teams prioritize data classification, key management, and robust access controls rather than mistakenly assuming cloud hosting automatically secures sensitive corporate data.
Physical infrastructure management encompasses the physical security of data center buildings, environmental controls (cooling and power redundancy), and the maintenance, replacement, and disposal of physical server hardware, racks, and cabling.
In public cloud environments like Azure, physical data center security and hardware maintenance are never the customer's responsibility. Microsoft owns and manages all global data centers, biometric building access, physical rack security, and hardware lifecycles across IaaS, PaaS, and SaaS models.
The organization operated a private, on-premises data center where physical facility security, power, cooling, and server maintenance were internal responsibilities.
Offloading physical infrastructure capital expenses and perimeter security overhead to the cloud vendor represents one of the primary cost and operational advantages of cloud computing.
This domain includes the type-1 hypervisor, physical network routers, switches, fiber connectivity, and server virtualization software that abstract underlying physical compute resources into virtual machines and cloud services.
Managing the physical network fabric and the hypervisor layer is the exclusive responsibility of Microsoft Azure across all public cloud service tiers. Customers interact with virtual network configurations (such as Network Security Groups and subnets), but they never manage or patch the physical routing hardware or core virtualization host software.
The organization deployed an on-premises virtualization environment (such as Hyper-V or VMware vSphere) where system administrators directly configure the host hypervisors and physical switches.
While customers configure logical boundary rules within virtual networks, the underlying physical infrastructure and hypervisors remain completely managed by Azure.
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