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Deploying Windows Servers in an Azure Availability Set

This guide demonstrates deploying Windows Server an Azure Availability Set for Windows Server IIS workloads.

An availability set logically groups virtual machines across fault domains and update domains within a single Azure data center. Fault domains provide physical hardware isolation (separate racks, power, and network switches), while update domains ensure Azure staggers platform maintenance, rebooting only one domain at a time with 30-minute recovery windows. VMs must be assigned to availability sets during creation and you cannot add existing VMs later.

Creating the First VM

1. Navigate to Azure Portal > Virtual Machines > Create


2. Create a new resource group (e.g., “Zava IIS”)


3. Name the VM (e.g., “Zava IIS 1”) and select region (e.g., East US 2)


4. Under Availability Options, select “Availability set” > Create New


5. Name the availability set and accept defaults (2 fault domains, 2 update domains)


6. Configure local admin account (avoid using “Administrator”)


7. Select “No inbound ports” for security


8. Enable Azure Hybrid Benefit if you have existing Windows Server licenses


9. Verify Premium SSD is selected under Disks (required for 99.95% SLA)


10. Note the virtual network name for subsequent VMs


11. Under Management, disable automatic shutdown and hotpatch


12. Under Monitoring, disable boot diagnostics


13. Review and create the VMAvailability-Set-Audio-Pre-avatar.txt​

Creating the Second VM

1. Return to Virtual Machines > Create


2. Use the same resource group


3. Name the second VM (e.g., “Zava IIS 2”)


4. Select the existing availability set created in step 4 above


5. Match all settings from the first VM (admin account, no inbound ports, hybrid benefit, Premium SSD)


6. Ensure the VM connects to the same virtual network as the first VM


7. Disable auto shutdown, hotpatch, and boot diagnostics


8. Review and create

Ensure that the VMs are configured with Premium SSD to achieve the highest possible SLA of 99.999%.

In a future post, we’ll cover how to configure Azure Application Gateway to load balance traffic across computers in an availability set as well as protecting against DDoS and OWASP top 10 attacks

Learn more about Azure Availability Sets