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Create a global load balancer with cross-subscription backends

  • Article

In this article, you learn how to create a global load balancer with cross-subscription backends.

A cross-subscription load balancer can reference a virtual network that resides in a different subscription other than the load balancers. This feature allows you to deploy a load balancer in one subscription and reference a virtual network in another subscription.

Prerequisites

  • Two Azure subscriptions.
  • An Azure account with active subscriptions. Create an account for free
  • A global public IP address deployed in Azure Subscription A.
  • A regional load balancer deployed in Azure Subscription B.
  • Azure PowerShell installed locally or Azure Cloud Shell.

If you choose to install and use PowerShell locally, this article requires the Azure PowerShell module version 5.4.1 or later. Run Get-Module -ListAvailable Az to find the installed version. If you need to upgrade, see Install Azure PowerShell module. If you're running PowerShell locally, you also need to run Connect-AzAccount to create a connection with Azure.

Important

All of the code samples will use example names and placeholders. Be sure to replace these with the values from your environment. The values needing replacement will be enclosed in angle brackets, like this: <example value>.

Sign in to Azure

With Azure PowerShell, you sign into Azure with Connect-AzAccount, and change your subscription context with Set-AzContext to Azure Subscription A. Then get the regional load balancer information with Get-AzLoadBalancer and `Get-AzLoadBalancerFrontendIpConfig. You need the Azure subscription ID, resource group name, and virtual network name from your environment.


# Sign in to Azure
Connect-AzAccount

# Set the subscription context to Azure Subscription A
Set-AzContext -Subscription '<Azure Subscription A>'     

# Get the Virtual Network information with Get-AzVirtualNetwork
$rlb= @{
    Name = '<regional load balancer name>'
    ResourceGroupName = '<Resource Group Subscription A>'
}
$RLB-info = Get-AzLoadBalancer @rlb
$RLBFE = Get-AzLoadBalancerFrontendIpConfig @ RLB-info

Create a resource group

In this section, you create a resource group in Azure Subscription B. This resource group is for all of your resources associate with your load balancer.

With Azure PowerShell, you switch the subscription context with Set-AzContext and create a resource group with New-AzResourceGroup.


# Set the subscription context to Azure Subscription B
Set-AzContext -Subscription '<Azure Subscription B>'  

# Create a resource group  
$rg = @{
    Name = 'myResourceGroupLB'
    Location = 'westus'
}
New-AzResourceGroup @rg

Note

When create the resource group for your load balancer, use the same Azure region as the virtual network in Azure Subscription A.

Create a global load balancer

In this section, you create the resources needed for the cross-region load balancer. A global standard sku public IP is used for the frontend of the cross-region load balancer.

With Azure PowerShell, you:

# Create global IP address for load balancer
$ip = @{
    Name = 'myPublicIP-CR'
    ResourceGroupName = ‘ Resource Group B’
    Location = 'eastus2'
    Sku = 'Standard'
    Tier = 'Global'
    AllocationMethod = 'Static'
}
$publicIP = New-AzPublicIpAddress @ip

# Create frontend configuration
$fe = @{
    Name = 'myFrontEnd-CR'
    PublicIpAddress = $publicIP
}
$feip = New-AzLoadBalancerFrontendIpConfig @fe

# Create backend address pool
$be = @{
    Name = 'myBackEndPool-CR'
}
$bepool = New-AzLoadBalancerBackendAddressPoolConfig @be

# Create the load balancer rule
$rul = @{
    Name = 'myHTTPRule-CR'
    Protocol = 'tcp'
    FrontendPort = '80'
    BackendPort = '80'
    FrontendIpConfiguration = $feip
    BackendAddressPool = $bepool
}
$rule = New-AzLoadBalancerRuleConfig @rul

# Create cross-region load balancer resource
$lbp = @{
    ResourceGroupName = ‘ Resource Group B’
    Name = 'myLoadBalancer-CR'
    Location = ‘eastus2’
    Sku = 'Standard'
    Tier = 'Global'
    FrontendIpConfiguration = $feip
    BackendAddressPool = $bepool
    LoadBalancingRule = $rule
}
$lb = New-AzLoadBalancer @lbp

Add load balancer frontends to cross-region load balancer

In this section, you add a frontend IP configuration to the cross-region load balancer.

With Azure PowerShell, you:


## Create the cross-region backend address pool configuration for region 2 ##
$RLB-BAF = @{
    Name = 'MyBackendPoolConfig-RLB'
    LoadBalancerFrontendIPConfigurationId = $RLBFE.Id
}
$beaddressconfigRLB = New-AzLoadBalancerBackendAddressConfig @region2ap

## Apply the backend address pool configuration for the cross-region load balancer ##
$bepoolcr = @{
    ResourceGroupName = ‘ Resource Group B’
    LoadBalancerName = 'myLoadBalancer-CR'
    Name = 'myBackEndPool-CR'
    LoadBalancerBackendAddress = $beaddressconfigRLB
}
Set-AzLoadBalancerBackendAddressPool @bepoolcr