Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A company uses Azure Blueprints to enforce a standard landing zone for all development subscriptions. The blueprint includes a virtual network, subnets, and network security groups. After the blueprint is assigned to a subscription, a development team manually adds a new subnet to the virtual network. The company plans to update the blueprint to add a new network security group rule. When the updated blueprint is published and the assignment is updated, what will happen to the manually added subnet?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
The manually added subnet will be removed because the blueprint definition now takes precedence.
This is incorrect. Azure Blueprints use incremental deployment mode, which does not delete resources that exist but are not defined in the blueprint. The manually added subnet is not part of the blueprint definition, so it is not removed.
B
Best answer
The manually added subnet will be preserved because blueprints do not manage resources after creation.
This is correct. By default, Azure Blueprints do not actively manage resources after they are deployed. When the blueprint assignment is updated, only the resources defined in the blueprint are added or modified; manually added resources that are not in the blueprint remain unchanged.
C
Distractor review
The manually added subnet will be overwritten by the updated blueprint definition.
This is incorrect. The updated blueprint definition includes only the original subnets and a new network security group rule; it does not include the manually added subnet. Therefore, it will not be overwritten.
D
Distractor review
The blueprint update will fail because the subnet already exists.
This is incorrect. The presence of an extra subnet that is not defined in the blueprint does not cause a failure. The blueprint update simply applies its template; existing resources that conflict may cause an error only if the template attempts to create a resource that already exists and the properties are different, but a manually added subnet is not being recreated by the blueprint.
Common exam trap
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Technical deep dive
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
- CIDR notation defines the prefix length.
- Block size helps identify subnet boundaries.
- Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
- The required host count determines the smallest suitable subnet.
TExam Day Tips
- Write the block size before choosing the subnet.
- Check whether the question asks for hosts, subnets or a specific address range.
- Do not confuse /24, /25, /26 and /27 host counts.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
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Question 2
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Question 3
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Question 4
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Question 5
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Question 6
A company develops a web API that runs on Azure App Service. The development team wants to deploy a new version of the API to a staging environment, run integration tests against it, and then gradually shift production traffic to the new version. If any issues are detected, they want to immediately roll back to the previous version without redeploying. Which Azure App Service feature should the team use to meet these requirements?
FAQ
Questions learners often ask
What does this AZ-900 question test?
CIDR notation defines the prefix length.
What is the correct answer to this question?
The correct answer is: The manually added subnet will be preserved because blueprints do not manage resources after creation. — Azure Blueprints deploy resources using Azure Resource Manager templates in incremental mode by default. When a blueprint assignment is updated, only the resources defined in the blueprint are affected. Resources that were manually created and are not part of the blueprint definition—such as the manually added subnet—are preserved and not removed or overwritten. To prevent manual modifications, a resource lock can be applied via the blueprint assignment, but that is not the case in this scenario.
What should I do if I get this AZ-900 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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