Availability Set should have at least 2 fault domains

Medium Azure General availabilitysets-availability-least-fault-domains

Applies to

Microsoft.Compute/availabilitySets

What CGPulse checks

A resource passes this rule when faultDomainCount greaterthanorequal 2. Anything else is reported as a finding with the evaluated property value attached as evidence.

How to fix it

Configure at least 2 fault domains to protect VMs from hardware failures. In Azure Portal: Availability Set > Properties > verify fault domain count. See: https://learn.microsoft.com/en-us/azure/virtual-machines/availability-set-overview

CLI

az vm availability-set update --ids "{id}" --platform-fault-domain-count 2

Bicep

resource availabilitySet 'Microsoft.Compute/availabilitySets@2024-03-01' = {{
  name: '{name}'
  location: location
  properties: {{
    platformFaultDomainCount: 2
    platformUpdateDomainCount: 5
  }}
  sku: {{
    name: 'Aligned'
  }}
}}

Terraform

resource "azurerm_availability_set" "{name}" {
  name                         = "{name}"
  resource_group_name          = "{rg}"
  location                     = var.location
  platform_fault_domain_count  = 2
  platform_update_domain_count = 5
  managed                      = true
}

Compliance frameworks

Cloud Security: Azure Foundations

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