Azure Cross-Region (Global) Load Balancer – Demo Environment

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As you may have seen, the Cross-Region (Global) Azure Load Balancer has recently become Generally Available (10th July 2023) – https://azure.microsoft.com/en-gb/updates/azure-s-crossregion-load-balancer-is-now-generally-available/. I decided therefore to create a test and demo environment for it – whereby a quick example can be deployed to get started.

✅ For a detailed overview of Cross-Region Load Balancer, please see here: https://learn.microsoft.com/en-us/azure/load-balancer/cross-region-overview 

Overview

The Cross-Region Load Balancer provides a number of key features that extend the functionality of Azure’s Load Balancers across multiple Regions, with a focus on Global Availability. The key features are:

  • Ultra Low Latency
  • IP Controls
  • Ability to scale up/down behind a single endpoint
  • High Availability
  • SLA backing
  • UDP Support
  • Floating IP

You can read more about the features in the announcement blog post here: https://techcommunity.microsoft.com/t5/azure-networking-blog/distribute-global-traffic-with-ultra-low-latency-using-azure/ba-p/3857991.

Demo Environment

To provide an environment to test the features and allow demonstration, I have written a small Lab environment in Terraform that deploys the infrastructure shown in the diagram below. The idea behind this Lab is to show how Cross-Region (Global) Load Balancing could be used to Load Balance a globally distributed Web Application that is deployed across multiple regions.

✅ Click Here for the Lab Environment Code – Feel free to download, use and modify the code for your own Labs and Learning!

Diagram showing Cross Region (Global) Load Balancer environment
Cross Region (Global) Load Balancer demo environment created using Terraform.
This environment provides the following:
  • Resource Groups in 3 Regions.
  • An Azure Key Vault with a Secret that’s used as the VM Admin Password.
  • 3 Virtual Machines in 3 Regions with IIS installed, and a PowerShell script that sets the IIS page to the VM hostname (so we can confirm where the Load Balancer is sending us to).
  • NICs for the VMs
  • VNets, Subnets, and NSGs – note that Standard SKU Load Balancers are secure by default, so require an NSG to allow inbound access.
  • Standard SKU Public IP Addresses in 3 Regions.
  • Standard SKU Regional Load Balancers in 3 Regions.
  • A Cross-Region (Global Load Balancer) that balances traffic across the 3 Regional Load Balancers.

Once deployed, you will have a Cross-Region (Global SKU) Load Balancer deployed that can be used as the access point for testing the Lab:

Cross Region (Global) Load Balancer
Cross Region (Global) Load Balancer

Testing

Testing the environment is simple – each Regional Load Balancer has a Public IP, with a DNS Label, so you can test each Region directly. The Cross-Region (Global) Load Balancer can then be used to test access across the entire infrastructure – and shutting down servers within the environment will force this to failover to another Regional endpoint – all of which can be accessed via the Cross-Region (Global) Load Balancer endpoint.

For example, in normal operation traffic will be sent across all 3 Regions based on the configured Load Balancing Rules, however, in a situation like the below – where a Region is down, traffic would be sent to the remaining Regions, again based on the configured Load Balancing Rules:

Cross Region (Global) Load Balancer demo environment - with a Region shown as down.
Cross Region (Global) Load Balancer demo environment – with a Region shown as down.
Deployment in Terraform

Deployment of the Cross-Region (Global) Load Balancer in Terraform is simple and follows the same conventions as a Standard Load Balancer, albeit with the sku_tier set to “Global“:

# Cross Region Load Balancer
resource "azurerm_lb" "cross-region-lb" {
  name                = "cross-region-lb-${var.regions.region1.location}"
  location            = var.regions.region1.location
  resource_group_name = "rg-${var.regions.region1.location}-con"
  sku                 = "Standard"
  sku_tier            = "Global"

  frontend_ip_configuration {
    name                 = "PublicIPAddress"
    public_ip_address_id = azurerm_public_ip.pip-cr-lb.id
  }
}

✅ I hope this environment is helpful and illustrates how and where the Cross-Region (Global) Load Balancer can be used. Thanks for reading!

Resources and further Reading:
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