Azure Resource Locks: Protect Critical Resources from Accidental Changes
Which Azure feature allows you to prevent accidental deletion or modification of critical Azure resources?
Quick Answer
The answer is Azure Resource Locks, the feature designed to prevent accidental deletion of Azure resources and safeguard critical infrastructure from unintended changes. This is correct because Resource Locks operate at the subscription, resource group, or individual resource level, enforcing either a CanNotDelete lock—which blocks deletion while still permitting modifications—or a ReadOnly lock, which prevents both deletion and modification entirely. On the Microsoft Azure Fundamentals AZ-900 exam, this concept tests your understanding of governance and protection mechanisms, often appearing in scenario-based questions where you must choose the right tool to secure a production database or virtual machine from human error. A common trap is confusing Resource Locks with Role-Based Access Control (RBAC); remember that locks override all permissions, even for the Owner role, making them a final safety net. For a quick memory tip, think of a padlock on a door: CanNotDelete locks the door shut but lets you paint it, while ReadOnly locks it completely and throws away the key.
⚠ Common exam trap
Watch out — candidates often confuse Azure Policy (which enforces rules during creation) with Resource Locks (which protect existing resources from deletion/modification), or they assume RBAC alone is sufficient to prevent accidental changes by authorized users.
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
✓
Azure Resource Locks
Azure Resource Locks are designed to prevent accidental deletion or modification of critical Azure resources by applying a lock at the subscription, resource group, or resource level. There are two types: CanNotDelete (prevents deletion but allows modifications) and ReadOnly (prevents both deletion and modification). This directly addresses the scenario of protecting resources from unintended changes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Azure RBAC
Why it's wrong here
Azure RBAC controls who may perform operations by assigning roles, but a permitted contributor can still delete a resource; it governs authorisation, not deletion protection. It is correct when the requirement is least-privilege access management rather than guarding against accidental removal.
- ✗
Azure Policy
Why it's wrong here
Azure Policy evaluates and audits or denies non-compliant resource configurations, but it does not place a lock on an existing resource to block deletion. It is the right choice for enforcing organisational standards such as allowed SKUs or required tags.
- ✓
Azure Resource Locks
Why this is correct
Resource Locks apply a deny assignment over a subscription, resource group or individual resource, blocking deletion (CanNotDelete) or any modification (ReadOnly) regardless of RBAC permissions. This directly prevents accidental changes to critical resources, satisfying the stated requirement.
- ✗
Azure Blueprints
Why it's wrong here
Azure Blueprints packages role assignments, policies and ARM templates for repeatable environment deployment, so it governs how resources are provisioned, not their ongoing protection. Resource locks are the mechanism that blocks deletion or modification. Blueprints would be the right choice when standardising compliant landing zones across subscriptions.
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Azure Resource Locks and Tags
Key term
Resource group
A logical container in Microsoft Azure that holds related resources for an application or solution, enabling unified management, security, and billing.
Key term
Feature
A feature is a distinct unit of functionality that delivers value to the user, often managed and tracked throughout the software development lifecycle.
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Same concept, more angles
1 more way this is tested on AZ-900
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which Azure security feature prevents accidental deletion of a critical production resource group?
medium- A.Assigning Reader role to all users
- ✓ B.Applying a CanNotDelete resource lock to the resource group
- C.Setting an Azure Policy to deny resource group deletion
- D.Enabling Azure Backup for the resource group
Why B: A CanNotDelete resource lock prevents any user or process from deleting the resource group, regardless of their permissions (including Owner). This is the correct mechanism to guard against accidental deletion of critical production resources because it overrides role-based access control (RBAC) permissions for delete operations.
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.