AZ-104 Deploy and Manage Azure Compute Practice Question
You need to deploy several identical virtual machines and ensure that the failure of a single Azure host does not affect all of them. Which feature should you use?
⚠ Common exam trap
It's easy for candidates to confuse availability sets with availability zones, thinking zones are required for host failure isolation, but availability sets provide fault domain isolation within a single datacenter, which is sufficient for the stated requirement.
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
✓
An availability set
An availability set distributes virtual machines across multiple fault domains (physical hosts) and update domains within an Azure datacenter. By placing VMs in an availability set, you ensure that a failure of a single Azure host (fault domain) does not affect all VMs, as each VM is placed on a different physical host. This meets the requirement for isolation from a single host failure.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
An availability set
Why this is correct
An availability set ensures the deployed VMs are placed on different fault domains (distinct physical hardware, power, and network) and update domains (distinct maintenance schedules). This configuration guarantees that at least one VM remains available during either planned Azure maintenance or an unexpected hardware failure, and it is required to qualify for the 99.95% VM SLA. For identical, redundant VMs, an availability set is the standard resilience mechanism.
- ✗
A proximity placement group
Why it's wrong here
A proximity placement group logically aligns VMs within the same Azure region and possibly the same data center to achieve the lowest possible network latency between them. This grouping increases the blast radius because all VMs can share the same rack and power source, so a single failure can take down the entire group. It is designed for performance-sensitive workloads, not for resilience, and can actually worsen availability.
When this WOULD be correct
You need to deploy several VMs that require the lowest possible network latency between them, such as for a high-performance computing (HPC) application or a latency-sensitive distributed database. The question would specify that high network performance is the primary requirement, not fault tolerance.
- ✗
A private endpoint
Why it's wrong here
A private endpoint assigns a network interface with a private IP address in a virtual network to an Azure PaaS service such as Storage or SQL Database, enabling traffic to remain on the Microsoft backbone. It applies to platform services, not to placement of virtual machines, and has no effect on fault domains, update domains, or VM uptime. Therefore, it is irrelevant to making several identical VMs resilient.
When this WOULD be correct
You need to ensure that traffic to an Azure Storage account from a virtual network does not traverse the public internet. A private endpoint would be the correct answer.
- ✗
A custom script extension
Why it's wrong here
The custom script extension is an Azure VM extension that downloads and executes a script on the VM after provision, enabling software installation or configuration drift correction. It performs no placement or redundancy functions, and it cannot influence which physical server, rack, or data center a VM runs on. Thus, while useful for setup, it provides zero protection against hardware failures or maintenance outages.
When this WOULD be correct
When the question asks how to automatically install software or run configuration scripts on a VM after it is provisioned, such as installing an antivirus agent or joining a domain.
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-104 exam frequently reuses these exact scenarios with slightly different constraints.
✓An availability setCorrect answer▾
Why this is correct
An availability set ensures the deployed VMs are placed on different fault domains (distinct physical hardware, power, and network) and update domains (distinct maintenance schedules). This configuration guarantees that at least one VM remains available during either planned Azure maintenance or an unexpected hardware failure, and it is required to qualify for the 99.95% VM SLA. For identical, redundant VMs, an availability set is the standard resilience mechanism.
✗A proximity placement groupWrong answer — click to see why▾
Why this is wrong here
A proximity placement group reduces network latency between VMs by placing them close together, but it does not protect against the failure of a single Azure host. In fact, it increases the risk of simultaneous failure because VMs are placed in close proximity, potentially on the same host.
★ When this WOULD be the correct answer
You need to deploy several VMs that require the lowest possible network latency between them, such as for a high-performance computing (HPC) application or a latency-sensitive distributed database. The question would specify that high network performance is the primary requirement, not fault tolerance.
Why candidates choose this
Candidates may confuse 'proximity' with 'availability' or think that grouping VMs together somehow provides redundancy, not realizing that proximity actually increases the risk of correlated failures.
✗A private endpointWrong answer — click to see why▾
Why this is wrong here
A private endpoint provides secure connectivity to Azure PaaS services over a private IP address, not fault tolerance for VMs. It does not isolate VMs from host failures.
★ When this WOULD be the correct answer
You need to ensure that traffic to an Azure Storage account from a virtual network does not traverse the public internet. A private endpoint would be the correct answer.
Why candidates choose this
Candidates may confuse 'private' with 'isolated' or think that a private endpoint provides some form of redundancy or fault isolation.
✗A custom script extensionWrong answer — click to see why▾
Why this is wrong here
A custom script extension is used to run scripts on VMs after deployment, not to provide high availability or fault isolation across hosts.
★ When this WOULD be the correct answer
When the question asks how to automatically install software or run configuration scripts on a VM after it is provisioned, such as installing an antivirus agent or joining a domain.
Why candidates choose this
Candidates may confuse the need for post-deployment automation with the requirement for fault tolerance, thinking that running a script can somehow mitigate host failures.
Analysis generated from the official AZ-104blueprint 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
Managed Identities for Azure Resources
Key term
Availability
Availability is the measure of how often a system or service is operational and accessible when needed, typically expressed as a percentage of uptime.
Key term
Azure datacenter
An Azure datacenter is a physical facility that houses Microsoft's cloud computing infrastructure, including servers, storage, and networking equipment, to deliver Azure services globally.
About these practice questions
Courseiva writes every AZ-104 question from scratch — 1,049 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-104 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-104 exam.