AZ-104 Deploy and Manage Azure Compute Practice Question
Two line-of-business VMs in a single region must stay available if one physical host is patched or fails. A zone failure is not part of the requirement. Which three actions should the administrator take? Select three.
⚠ Common exam trap
A common mix-up: candidates confuse availability sets (protecting against host failure) with availability zones (protecting against datacenter failure), leading them to select zone-based deployment when the requirement only specifies a single host failure scenario.
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
✓
Create an availability set for the application VMs before deployment.
An availability set ensures that VMs are placed on different fault domains (physical hosts) and update domains within a single Azure region, protecting against physical host patching or failure. This meets the requirement of keeping VMs available during a single host event without requiring zone-level redundancy.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Create an availability set for the application VMs before deployment.
Why this is correct
Creating an availability set before deploying the VMs is mandatory because Azure does not allow you to add an existing VM into an availability set after creation; the VM must be placed into the set at the time of provisioning. By defining the availability set first, you ensure that both VMs are created with the set's fault and update domain constraints applied from the start, which is the foundational step for achieving the 99.95% availability SLA for multi-instance deployments. Without this upfront creation, the workload cannot be properly distributed across distinct failure boundaries.
- ✓
Deploy both VMs into the same availability set.
Why this is correct
Deploying both VMs into the same availability set is what enables Azure to place them across different fault domains and update domains automatically. If the VMs were in separate availability sets, they could end up sharing the same physical rack (fault domain) or be rebooted together during a planned maintenance event (update domain), eliminating the redundancy benefit. Only a single availability set groups the VMs so that Azure's placement algorithm can maximize their isolation from each other, reducing the blast radius of host-level failures.
- ✓
Allow Azure to place the VMs across different fault and update domains within the availability set.
Why this is correct
Fault and update domain distribution is the main benefit of an availability set. Azure handles the placement automatically once the VMs are in the set, reducing the chance that a single maintenance event affects all instances.
- ✗
Deploy the VMs in separate availability zones to protect against a datacenter outage.
Why it's wrong here
Availability zones protect against a full datacenter outage by placing VMs in different physical zones, but this far exceeds the stated requirement of remaining available during host-level maintenance or hardware failures. Moreover, availability sets and availability zones are mutually exclusive placement mechanisms for standard VMs—you cannot place a VM in both simultaneously, and zone deployment introduces cross-zone network latency and additional cost. For a two-VM workload that only needs resilience within a single datacenter, an availability set is the targeted, cost-effective solution, making zones an overprovisioned and less precise choice.
When this WOULD be correct
If the requirement were to protect against a full datacenter outage (e.g., due to power or network failure), deploying VMs across separate availability zones would be the correct answer to ensure high availability across zones.
- ✗
Use a single larger VM and rely on snapshots for uptime.
Why it's wrong here
Using a single larger VM removes redundancy entirely, creating a single point of failure; if the host experiences a hardware fault or the VM crashes, the application goes down with no automatic failover. Snapshots are point-in-time backups that restore data to a new disk, but restoring from a snapshot can take minutes and requires manual intervention or an external orchestration tool, so it does not provide continuous availability. This approach addresses disaster recovery, not high availability, because it cannot seamlessly redirect traffic or restart the workload within the required uptime window.
When this WOULD be correct
This option would be correct in a scenario where the requirement is to minimize downtime during planned maintenance or failure by using Azure Site Recovery or backup, and the focus is on disaster recovery rather than high availability within a single region. For example, if the question asked for a cost-effective solution to protect against data loss with a recovery time objective (RTO) of hours, not minutes.
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.
✓Create an availability set for the application VMs before deployment.Correct answer▾
Why this is correct
Creating an availability set before deploying the VMs is mandatory because Azure does not allow you to add an existing VM into an availability set after creation; the VM must be placed into the set at the time of provisioning. By defining the availability set first, you ensure that both VMs are created with the set's fault and update domain constraints applied from the start, which is the foundational step for achieving the 99.95% availability SLA for multi-instance deployments. Without this upfront creation, the workload cannot be properly distributed across distinct failure boundaries.
✗Deploy the VMs in separate availability zones to protect against a datacenter outage.Wrong answer — click to see why▾
Why this is wrong here
The requirement specifies that a zone failure is not part of the requirement, so deploying VMs in separate availability zones is unnecessary and does not address the need to protect against a single physical host failure or patching event.
★ When this WOULD be the correct answer
If the requirement were to protect against a full datacenter outage (e.g., due to power or network failure), deploying VMs across separate availability zones would be the correct answer to ensure high availability across zones.
Why candidates choose this
Candidates may confuse availability zones with availability sets, thinking that zones provide similar protection against host failures, or they may over-engineer the solution by adding zone-level redundancy when it is not required.
✗Use a single larger VM and rely on snapshots for uptime.Wrong answer — click to see why▾
Why this is wrong here
Using a single larger VM with snapshots does not provide high availability; if the host fails, the VM is unavailable until restored from a snapshot, which can take significant time and may lose data. The requirement is for continuous availability during host patching or failure, not just data protection.
★ When this WOULD be the correct answer
This option would be correct in a scenario where the requirement is to minimize downtime during planned maintenance or failure by using Azure Site Recovery or backup, and the focus is on disaster recovery rather than high availability within a single region. For example, if the question asked for a cost-effective solution to protect against data loss with a recovery time objective (RTO) of hours, not minutes.
Why candidates choose this
Candidates may think that a larger VM with snapshots offers redundancy or failover capability, confusing data protection (backups) with high availability (redundant instances). They might also assume that snapshots can be used to quickly spin up a new VM, overlooking the time and manual intervention required.
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 set
An Availability set is a cloud computing feature that groups virtual machines across multiple fault domains and update domains to ensure high availability during hardware failures or planned maintenance.
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.
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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.