Azure Virtual Machines

What is an Azure virtual machine?

VM options in Azure

Azure Virtual Machines (standard)

The core IaaS offering. You choose:

• Size — from 1 vCPU / 0.5 GB RAM to 416 vCPUs / 12 TB RAM
• Image — Windows Server, Ubuntu, Red Hat, custom images
• Region — where the VM physically runs
• Disk — OS disk + optional data disks

Azure Virtual Machine Scale Sets

Scale Sets let you deploy and manage a group of identical VMs that automatically scale based on demand:

Feature	Single VM	VM Scale Set
Number of VMs	1	1 to 1,000+
Auto-scaling	No (manual)	Yes (rules-based)
Load balancing	Must add separately	Built-in
Identical config	N/A	All VMs are identical
Best for	Dev/test, single workloads	Web apps, APIs, batch processing

Summit Construction uses a Scale Set for their project portal:

• Normal: 2 VMs
• Peak (quarterly reviews): auto-scales to 8 VMs
• After peak: scales back to 2 VMs

Availability sets

Availability sets protect against hardware failures within a datacenter by spreading VMs across:

• Fault domains — separate physical racks (protects against rack-level failures)
• Update domains — VMs that can be rebooted during maintenance without all going down at once

Concept	What It Protects Against
Fault domains	Physical hardware failure (rack, power, network switch)
Update domains	Planned maintenance (Azure reboots VMs in one update domain at a time)

💡 Availability sets vs availability zones

Both protect against failures, but at different scales:

• Availability sets protect within a single datacenter (rack-level failures)
• Availability zones protect across datacenters within a region

For the highest availability within a region, use availability zones. Availability sets are the older approach and still work, but zones provide stronger protection.

Exam tip: If a question asks for the HIGHEST availability, the answer is usually availability zones, not availability sets.

Azure Virtual Desktop

Azure Virtual Desktop (AVD) is a desktop and app virtualisation service:

• Users access a full Windows desktop or individual apps from any device
• The desktop runs in Azure, not on the user’s computer
• Supports multi-session Windows 11 (unique to Azure — no other cloud offers this)

Harbour Health use case: Doctors access patient records from personal devices through Azure Virtual Desktop. The data never leaves Azure — only screen pixels are sent to the device. This satisfies compliance requirements while enabling remote work.

Resources required for a VM

When you create a VM, Azure also creates (or requires) these supporting resources:

Resource	Required?	Purpose
Virtual network (VNet)	Yes	Network connectivity
Network interface (NIC)	Yes	Connects the VM to the VNet
OS disk	Yes	Stores the operating system (managed disk)
Public IP address	Optional	Allows internet access to the VM
Network security group (NSG)	Recommended	Firewall rules for inbound/outbound traffic
Data disks	Optional	Additional storage for applications and data

Key exam concept: A VM is not just a VM — it’s a collection of resources. When you delete a VM, you should also clean up the NIC, disks, and public IP, or they’ll keep incurring charges.

ℹ️ VM sizing families

Azure organises VM sizes into families based on workload type:

Family	Optimised For	Example Use Case
B-series	Burstable, low cost	Dev/test, small web servers
D-series	General purpose	Most production workloads
E-series	Memory-optimised	Databases, in-memory analytics
F-series	Compute-optimised	Batch processing, gaming servers
N-series	GPU-enabled	AI/ML training, video rendering

The AZ-900 exam doesn’t test specific VM sizes, but understanding the concept of families and that VMs come in different sizes for different workloads is important.

🎬 Video walkthrough

🎬 Video coming soon

Azure Virtual Machines — AZ-900

Azure Virtual Machines — AZ-900

~10 min

Flashcards

Question

What is a Virtual Machine Scale Set?

Click or press Enter to reveal answer

Answer

A group of identical VMs that automatically scale based on demand. They include built-in load balancing and can scale from 1 to 1,000+ instances based on rules you define.

Click to flip back

💡 Show hint

Question

What is the difference between fault domains and update domains?

Click or press Enter to reveal answer

Answer

Fault domains protect against physical hardware failures (separate racks). Update domains protect against planned maintenance downtime (Azure reboots one update domain at a time, not all at once).

Click to flip back

Question

What resources are REQUIRED when creating an Azure VM?

Click or press Enter to reveal answer

Answer

Virtual network (VNet), network interface (NIC), and OS disk. Public IP, NSG, and data disks are optional but recommended.

Click to flip back

💡 Show hint

Question

What is Azure Virtual Desktop?

Click or press Enter to reveal answer

Answer

A desktop and app virtualisation service that runs Windows desktops in Azure. Users access them from any device. Supports multi-session Windows 11 (unique to Azure). Data stays in Azure — only screen pixels are transmitted.

Click to flip back

Knowledge Check

Knowledge Check

Summit Construction's project portal experiences unpredictable traffic spikes during quarterly reviews. Which Azure VM feature automatically adds more VMs during high demand and removes them when demand drops?

AAvailability sets — distribute VMs across fault domainsBAzure Virtual Desktop — provide remote desktop accessCVM Scale Sets — automatically scale the number of identical VMsDAvailability zones — distribute VMs across datacenters

Check Answer

Knowledge CheckSelect all that apply

Which of the following resources are REQUIRED when creating an Azure VM? (Select THREE)

AVirtual network (VNet)BPublic IP addressCNetwork interface (NIC)DOS diskEData disk

Check Answer

---

Next up: More Azure compute options — containers, Azure Functions, and Azure App Service.