AZ-900 Describe cloud concepts Practice Question
Which of the following best describes the 'shared responsibility' for operating system updates under the IaaS model?
⚠ Common exam trap
It's easy for candidates to assume the cloud provider handles all security updates, confusing IaaS with PaaS or SaaS where the provider does manage the OS, leading them to incorrectly select option A or D.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The customer is responsible for patching the guest OS in IaaS VMs
Under the Infrastructure as a Service (IaaS) model, the cloud provider is responsible for the physical infrastructure and the hypervisor, but the customer retains control over the guest operating system running inside the virtual machine. Therefore, the customer is responsible for patching and updating the guest OS, including applying security updates and managing configuration. This aligns with the shared responsibility model where the customer manages anything they deploy on top of the abstracted infrastructure.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The cloud provider is responsible for patching the OS in IaaS VMs
Why it's wrong here
Under the shared responsibility model for IaaS, the cloud provider's security obligations stop at the virtualization boundary. Azure manages the hypervisor, hardware, and network infrastructure, but does not patch the guest OS running inside a customer's VM. Therefore, claiming the provider handles OS patching for IaaS mistakenly transfers an obligation that remains firmly with the customer.
- ✓
The customer is responsible for patching the guest OS in IaaS VMs
Why this is correct
When deploying an IaaS VM, Azure provides the virtual machine with a preconfigured operating system, but the customer takes on administration duties, including patch management. The customer must regularly update the guest OS with security patches and hotfixes to protect applications and data. Azure's responsibility extends only to the physical host and hypervisor, not to the operating system inside the VM.
- ✗
Both customer and provider share equal responsibility for OS patches in IaaS
Why it's wrong here
In the shared responsibility model, Azure's responsibilities are limited to the physical datacenter, network, and hypervisor. The customer, however, retains full control over the guest OS, making OS patching entirely their obligation, not a 50/50 arrangement. Any suggestion of equal shared patching conflates IaaS with PaaS or SaaS, where the platform provider handles more of the stack.
- ✗
OS patching is not required in cloud environments as Azure handles this automatically
Why it's wrong here
This statement falsely implies patches are unnecessary because Azure automatically secures all cloud workloads. In reality, Azure only applies automatic OS updates to platform-managed services like PaaS or SaaS offerings. For IaaS VMs, the customer is fully accountable for evaluating, approving, and applying guest OS patches, so patching remains mandatory.
Go deeper
Related to this question
Learn chapter
What is Cloud Computing?
Key term
Security
Security in IT is the practice of protecting systems, networks, and data from unauthorized access, damage, or theft.
Key term
Shared responsibility
Shared responsibility is a cloud security model where the cloud provider and the customer each own distinct parts of security and compliance duties.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-900 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AZ-900 exam.