AZ-900 Describe Azure management and governance Practice Question
A company uses Azure Policy to require encryption on storage accounts. They want to automatically deploy an encryption extension to any new storage account that does not have it enabled, without manual intervention. Which policy effect should they use?
⚠ Common exam trap
A common mix-up: candidates confuse AuditIfNotExists (which only audits) with DeployIfNotExists (which deploys), mistakenly thinking auditing alone can enforce compliance without manual remediation.
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
✓
DeployIfNotExists
DeployIfNotExists is the correct effect because it evaluates resources after creation and automatically deploys a required configuration (like an encryption extension) if it is missing, without requiring manual intervention. This effect is specifically designed for scenarios where you need to remediate non-compliant resources by deploying a template or extension, ensuring encryption is enabled on all storage accounts.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
DeployIfNotExists
Why this is correct
DeployIfNotExists is a policy effect that evaluates an existing resource and, if non-compliant, deploys a supplemental resource from a linked template — for example, a storage encryption extension or a customer-managed key configuration. This effect creates new resources (not just edits properties) and is the correct way to automatically enforce encryption on storage accounts. It requires a managed identity and role assignments for the deployment, and it can also be run as a remediation task against existing resources.
- ✗
Modify
Why it's wrong here
Modify alters specific properties or tags of an existing resource during create/update or as a remediation task, but it is limited to changing in-place values and cannot provision any new resource such as an encryption extension. While encryption might be a property on some services, the requirement to deploy an extension (e.g., for Azure Security Center or Azure Backup) exceeds Modify's capability. Since the storage scenario demands a new dependent resource, Modify is incorrect.
When this WOULD be correct
A company wants to ensure all storage accounts have a specific tag (e.g., 'Environment: Production') and automatically add it if missing. Using Modify with a 'addOrReplace' operation would be correct to enforce tag compliance without deploying new resources.
- ✗
Append
Why it's wrong here
Append adds additional fields (like tags or a few allowed properties) to a resource template during deployment, but it cannot inject complex objects or create dependent resources like an encryption key or an extension. Importantly, Append only affects new resource creation or updates and does not remediate already-deployed, non-compliant storage accounts. Therefore, it is not suitable for enforcing encryption on existing storage.
When this WOULD be correct
Use Append when you need to add a tag or a setting (like enabling encryption) to a resource during creation or update, but the resource already supports the property and no extension deployment is needed.
- ✗
AuditIfNotExists
Why it's wrong here
AuditIfNotExists only checks whether a required resource or setting is present and writes a compliance and activity log entry if it is missing; it does not deploy or change anything. It is purely a monitoring effect, so even though it would flag a storage account lacking encryption, it would not satisfy the requirement to 'require encryption' because it takes no remediation action. Thus it cannot enforce the policy.
When this WOULD be correct
Use AuditIfNotExists when you only need to audit and report on resources that do not have a required extension or configuration, without automatic remediation. For example, auditing VMs missing a required monitoring agent.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The AZ-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓DeployIfNotExistsCorrect answer▾
Why this is correct
DeployIfNotExists is a policy effect that evaluates an existing resource and, if non-compliant, deploys a supplemental resource from a linked template — for example, a storage encryption extension or a customer-managed key configuration. This effect creates new resources (not just edits properties) and is the correct way to automatically enforce encryption on storage accounts. It requires a managed identity and role assignments for the deployment, and it can also be run as a remediation task against existing resources.
✗ModifyWrong answer — click to see why▾
Why this is wrong here
Modify is used to add or change tags or other properties on existing resources, but it cannot deploy extensions or remediate non-compliance by deploying resources; DeployIfNotExists is designed for deploying resources like extensions when a condition is not met.
★ When this WOULD be the correct answer
A company wants to ensure all storage accounts have a specific tag (e.g., 'Environment: Production') and automatically add it if missing. Using Modify with a 'addOrReplace' operation would be correct to enforce tag compliance without deploying new resources.
Why candidates choose this
Candidates may confuse 'Modify' with 'DeployIfNotExists' because both can alter resources, but Modify changes properties on the resource itself, while DeployIfNotExists deploys additional resources like extensions.
✗AppendWrong answer — click to see why▾
Why this is wrong here
Append adds fields to a resource but cannot deploy extensions or trigger remediation tasks; it only modifies existing properties, not deploy new resources.
★ When this WOULD be the correct answer
Use Append when you need to add a tag or a setting (like enabling encryption) to a resource during creation or update, but the resource already supports the property and no extension deployment is needed.
Why candidates choose this
Candidates confuse Append with DeployIfNotExists because both can add configurations, but Append cannot deploy new resources like extensions.
✗AuditIfNotExistsWrong answer — click to see why▾
Why this is wrong here
AuditIfNotExists only audits compliance and reports non-compliant resources, but does not deploy any extension or take remediation action, so it cannot automatically enable encryption.
★ When this WOULD be the correct answer
Use AuditIfNotExists when you only need to audit and report on resources that do not have a required extension or configuration, without automatic remediation. For example, auditing VMs missing a required monitoring agent.
Why candidates choose this
Candidates may confuse auditing with remediation, thinking that 'AuditIfNotExists' includes automatic deployment, or they may overlook the requirement for automatic deployment in the question.
Analysis generated from the official AZ-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Go deeper
Related to this question
Learn chapter
Azure Cost Management and Billing
Key term
Azure Policy
Azure Policy is a service in Microsoft Azure that lets you create, assign, and manage rules to ensure your resources stay compliant with your company standards and service-level agreements.
Key term
Storage account
A cloud storage account is a container that holds a set of cloud storage services and their data, providing a unique namespace and access policies for storing and managing unstructured data.
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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.