Multi-Region Design

How to design global Azure deployments with multiple regions.

Multi-Region Architecture

Region Selection

Decision Factors

Factor	Consideration
Latency	User proximity
Compliance	Data residency requirements
Service Availability	Not all services in all regions
Cost	Pricing varies by region
Paired Regions	DR failover targets
Availability Zones	HA within region

Azure Paired Regions

Primary	Secondary	Notes
East US	West US	US customers
North Europe	West Europe	EU customers
Southeast Asia	East Asia	APAC customers
Australia East	Australia Southeast	ANZ customers
UK South	UK West	UK customers

Multi-Region Hub-Spoke

Architecture

IP Address Planning

Global Address Space: 10.0.0.0/8
├── East US (Primary): 10.0.0.0/10 (10.0.x.x - 10.63.x.x)
│   ├── Hub: 10.0.0.0/16
│   ├── Corp Spokes: 10.1.0.0/14 (10.1-4.x.x)
│   ├── Online Spokes: 10.16.0.0/14
│   └── Reserved: 10.32.0.0/11
│
├── West Europe (Secondary): 10.64.0.0/10 (10.64.x.x - 10.127.x.x)
│   ├── Hub: 10.100.0.0/16
│   ├── Corp Spokes: 10.101.0.0/14
│   ├── Online Spokes: 10.116.0.0/14
│   └── Reserved: 10.132.0.0/11
│
├── Southeast Asia: 10.128.0.0/10
└── Australia East: 10.192.0.0/10

Multi-Region Virtual WAN

Architecture

Bicep: Multi-Region Virtual WAN

resource virtualWan 'Microsoft.Network/virtualWans@2023-05-01' = {
  name: 'vwan-global-001'
  location: 'eastus'
  properties: {
    type: 'Standard'
    allowBranchToBranchTraffic: true
    allowVnetToVnetTraffic: true
  }
}

// East US Hub
resource hubEastUS 'Microsoft.Network/virtualHubs@2023-05-01' = {
  name: 'vhub-eastus-001'
  location: 'eastus'
  properties: {
    virtualWan: {
      id: virtualWan.id
    }
    addressPrefix: '10.0.0.0/23'
    sku: 'Standard'
  }
}

// West Europe Hub
resource hubWestEurope 'Microsoft.Network/virtualHubs@2023-05-01' = {
  name: 'vhub-westeurope-001'
  location: 'westeurope'
  properties: {
    virtualWan: {
      id: virtualWan.id
    }
    addressPrefix: '10.100.0.0/23'
    sku: 'Standard'
  }
}

// Hub routing intent for secure hub
resource routingIntentEUS 'Microsoft.Network/virtualHubs/routingIntent@2023-05-01' = {
  parent: hubEastUS
  name: 'routing-intent'
  properties: {
    routingPolicies: [
      {
        name: 'InternetTraffic'
        destinations: ['Internet']
        nextHop: firewallEastUS.id
      }
      {
        name: 'PrivateTraffic'
        destinations: ['PrivateTraffic']
        nextHop: firewallEastUS.id
      }
    ]
  }
}

Global Load Balancing

Azure Front Door

Bicep: Azure Front Door

resource frontDoor 'Microsoft.Cdn/profiles@2023-05-01' = {
  name: 'afd-global-001'
  location: 'global'
  sku: {
    name: 'Premium_AzureFrontDoor'
  }
}

resource endpoint 'Microsoft.Cdn/profiles/afdEndpoints@2023-05-01' = {
  parent: frontDoor
  name: 'app-endpoint'
  location: 'global'
  properties: {
    enabledState: 'Enabled'
  }
}

resource originGroupPrimary 'Microsoft.Cdn/profiles/originGroups@2023-05-01' = {
  parent: frontDoor
  name: 'primary-origins'
  properties: {
    loadBalancingSettings: {
      sampleSize: 4
      successfulSamplesRequired: 3
    }
    healthProbeSettings: {
      probePath: '/health'
      probeRequestType: 'HEAD'
      probeProtocol: 'Https'
      probeIntervalInSeconds: 30
    }
  }
}

resource originEastUS 'Microsoft.Cdn/profiles/originGroups/origins@2023-05-01' = {
  parent: originGroupPrimary
  name: 'eastus-origin'
  properties: {
    hostName: 'app-eastus.contoso.com'
    httpPort: 80
    httpsPort: 443
    priority: 1
    weight: 1000
  }
}

resource originWestEurope 'Microsoft.Cdn/profiles/originGroups/origins@2023-05-01' = {
  parent: originGroupPrimary
  name: 'westeurope-origin'
  properties: {
    hostName: 'app-westeurope.contoso.com'
    httpPort: 80
    httpsPort: 443
    priority: 2
    weight: 1000
  }
}

Data Replication

SQL Geo-Replication

Cosmos DB Multi-Region

resource cosmosAccount 'Microsoft.DocumentDB/databaseAccounts@2023-04-15' = {
  name: 'cosmos-global-001'
  location: 'eastus'
  kind: 'GlobalDocumentDB'
  properties: {
    databaseAccountOfferType: 'Standard'
    locations: [
      {
        locationName: 'eastus'
        failoverPriority: 0
        isZoneRedundant: true
      }
      {
        locationName: 'westeurope'
        failoverPriority: 1
        isZoneRedundant: true
      }
      {
        locationName: 'southeastasia'
        failoverPriority: 2
        isZoneRedundant: true
      }
    ]
    enableAutomaticFailover: true
    enableMultipleWriteLocations: true // Multi-master
    consistencyPolicy: {
      defaultConsistencyLevel: 'Session'
    }
  }
}

Deployment Patterns

Active-Passive

Active-Active

Quick Reference Card

Component	Multi-Region Pattern
Network	Hub per region + Global peering
Load Balancing	Azure Front Door / Traffic Manager
SQL	Failover Groups
Cosmos DB	Multi-region writes
Storage	GRS/GZRS
IP Planning	/10 per region

Next Steps

Continue to Hybrid Connectivity to learn about ExpressRoute, VPN, and Azure Arc.