Challenge 09: Virtual Machines & Availability
20-30 min | Cost: Free (exploration only) | Domain: Azure Architecture & Services (35-40%)
Exam skills covered
- Describe VM options (Azure VMs, VM Scale Sets, availability sets, Azure Virtual Desktop)
- Describe resources required for virtual machines
- Compare compute types (VMs, containers, functions)
Overview
Azure Virtual Machines (VMs) are IaaS compute resources that let you run Windows or Linux operating systems in the cloud. When you create a VM, Azure also creates several supporting resources: a virtual network interface, a disk, and (optionally) a public IP address.
To make VMs highly available, Azure offers Availability Sets (protect against hardware failures within a datacenter) and Availability Zones (protect against entire datacenter failures).
Explore
Task 1: Explore VM creation (don't create!)
- In the Azure Portal, click Create a resource → Virtual Machine
- Explore each tab without creating:
Basics tab:
- Subscription, Resource Group, VM name, Region
- Availability options: None, Availability Zone, Availability Set, Scale Set
- Image (OS): Windows Server, Ubuntu, Red Hat, etc.
- Size: Choose CPU/RAM combination
Disks tab:
- OS disk type: Premium SSD, Standard SSD, Standard HDD
Networking tab:
- Virtual network, subnet, public IP, NSG
- Click Cancel — just understanding what's needed
Task 2: Understand VM-related resources
When you create a VM, Azure creates:
| Resource | Purpose | Required? |
|---|---|---|
| Virtual Machine | The compute instance | Yes |
| OS Disk (Managed Disk) | Storage for the operating system | Yes |
| Network Interface (NIC) | Connects VM to a virtual network | Yes |
| Virtual Network | Network for the VM to communicate | Yes (new or existing) |
| Public IP Address | Allow internet access to the VM | Optional |
| Network Security Group | Firewall rules for the VM | Recommended |
Task 3: Understand availability options
| Option | Protects against | How it works |
|---|---|---|
| Availability Set | Hardware failures in a datacenter | VMs spread across fault domains and update domains |
| Availability Zone | Datacenter failures | VMs placed in different physical zones |
| VM Scale Set | Demand changes | Auto-scale number of identical VMs |
Fault domains = separate physical racks (power + network) Update domains = groups that can be rebooted together during maintenance
Task 4: Explore VM sizes
- In the Azure Portal, go to Virtual Machines → Create
- Click See all sizes (or the size selector)
- Browse the VM family categories:
| Family | Prefix | Best for |
|---|---|---|
| General purpose | B, D | Testing, dev, small databases |
| Compute optimized | F | CPU-intensive workloads |
| Memory optimized | E, M | Large databases, caching |
| Storage optimized | L | Big data, data warehousing |
| GPU | N | ML training, graphics rendering |
- Click Cancel
Task 5: Azure Virtual Desktop
Azure Virtual Desktop (AVD) is a related VM service:
- Provides virtual Windows desktops and apps
- Users access from any device via a browser or client
- IT manages the desktop centrally in Azure
- Multi-session Windows 10/11 (unique to Azure — not possible on-prem)
# List available VM sizes in a region
az vm list-sizes --location eastus --query "[0:10].{Name:name, Cores:numberOfCores, RAM_MB:memoryInMb}" --output table
# List available VM images
az vm image list --output table
# List VM images for Ubuntu
az vm image list --offer Ubuntu --all --query "[0:5]" --output table
Key Concepts
| Concept | Description |
|---|---|
| Azure VM | IaaS compute — you manage the OS and applications |
| Availability Set | Distributes VMs across fault/update domains within a datacenter |
| Availability Zone | Distributes VMs across physically separate datacenters |
| VM Scale Set | Group of identical VMs that auto-scale based on demand |
| Azure Virtual Desktop | Cloud-hosted desktops accessible from any device |
| Fault domain | Separate physical rack (protects against hardware failure) |
| Update domain | Logical grouping for planned maintenance reboots |
Knowledge Check
1. Which Azure feature distributes VMs across physically separate datacenters within a region?
2. When you create an Azure VM, which resource is automatically created to store the operating system?
3. A company needs to provide 100 employees with Windows 10 desktops that can be accessed from any device, anywhere. Which service should they use?
4. What is the purpose of VM Scale Sets?
5. In an Availability Set, what does a "fault domain" represent?
Learn More
- 📚 Study Guide AZ-900 — Curated study materials
- Microsoft Learn: Describe Azure compute and networking
- Azure VMs documentation