Load balance multiple websites

  • 07/15/2024

This script sample creates a virtual network with two virtual machines (VM) that are members of an availability set. A load balancer directs traffic for two separate IP addresses to the two VMs. After running the script, you could deploy web server software to the VMs and host multiple web sites, each with its own IP address.

To run this sample, install the latest version of the Azure CLI. To start, run az login to create a connection with Azure.

Samples for the Azure CLI are written for the bash shell. To run this sample in Windows PowerShell or Command Prompt, you may need to change elements of the script.

If you don't have an Azure trial subscription, create an Azure trial subscription before you begin.

Sample script

# !/bin/bash

RgName="MyResourceGroup"
Location="chinaeast"

# Create a resource group.
az group create \
  --name $RgName \
  --location $Location

# Create an availability set for the two VMs that host both websites.
az vm availability-set create \
  --resource-group $RgName \
  --location $Location \
  --name MyAvailabilitySet \
  --platform-fault-domain-count 2 \
  --platform-update-domain-count 2

# Create a virtual network and a subnet.
az network vnet create \
  --resource-group $RgName \
  --name MyVnet \
  --address-prefix 10.0.0.0/16 \
  --location $Location \
  --subnet-name MySubnet \
  --subnet-prefix 10.0.0.0/24

# Create three public IP addresses; one for the load balancer and two for the front-end IP configurations.
az network public-ip create \
  --resource-group $RgName \
  --name MyPublicIp-LoadBalancer \
  --allocation-method Dynamic
az network public-ip create \
  --resource-group $RgName \
  --name MyPublicIp-Contoso \
  --allocation-method Dynamic
az network public-ip create \
  --resource-group $RgName \
  --name MyPublicIp-Fabrikam \
  --allocation-method Dynamic

# Create a load balancer.
az network lb create \
  --resource-group $RgName \
  --location $Location \
  --name MyLoadBalancer \
  --frontend-ip-name FrontEnd \
  --backend-pool-name BackEnd \
  --public-ip-address MyPublicIp-LoadBalancer

# Create two front-end IP configurations for both web sites.
az network lb frontend-ip create \
  --resource-group $RgName \
  --lb-name MyLoadBalancer \
  --public-ip-address MyPublicIp-Contoso \
  --name FeContoso
az network lb frontend-ip create \
  --resource-group $RgName \
  --lb-name MyLoadBalancer \
  --public-ip-address MyPublicIp-Fabrikam \
  --name FeFabrikam

# Create the back-end address pools.
az network lb address-pool create \
  --resource-group $RgName \
  --lb-name MyLoadBalancer \
  --name BeContoso
az network lb address-pool create \
  --resource-group $RgName \
  --lb-name MyLoadBalancer \
  --name BeFabrikam

# Create a probe on port 80.
az network lb probe create \
  --resource-group $RgName \
  --lb-name MyLoadBalancer \
  --name MyProbe \
  --protocol Http \
  --port 80 --path /

# Create the load balancing rules.
az network lb rule create \
  --resource-group $RgName \
  --lb-name MyLoadBalancer \
  --name LBRuleContoso \
  --protocol Tcp \
  --probe-name MyProbe \
  --frontend-port 5000 \
  --backend-port 5000 \
  --frontend-ip-name FeContoso \
  --backend-pool-name BeContoso
az network lb rule create \
  --resource-group $RgName \
  --lb-name MyLoadBalancer \
  --name LBRuleFabrikam \
  --protocol Tcp \
  --probe-name MyProbe \
  --frontend-port 5000 \
  --backend-port 5000 \
  --frontend-ip-name FeFabrikam \
  --backend-pool-name BeFabrikam

# ############## VM1 ###############

# Create an Public IP for the first VM.
az network public-ip create \
  --resource-group $RgName \
  --name MyPublicIp-Vm1 \
  --allocation-method Dynamic

# Create a network interface for VM1.
az network nic create \
  --resource-group $RgName \
  --vnet-name MyVnet \
  --subnet MySubnet \
  --name MyNic-Vm1 \
  --public-ip-address MyPublicIp-Vm1

# Create IP configurations for Contoso and Fabrikam.
az network nic ip-config create \
  --resource-group $RgName \
  --name ipconfig2 \
  --nic-name MyNic-Vm1 \
  --lb-name MyLoadBalancer \
  --lb-address-pools BeContoso
az network nic ip-config create \
  --resource-group $RgName \
  --name ipconfig3 \
  --nic-name MyNic-Vm1 \
  --lb-name MyLoadBalancer \
  --lb-address-pools BeFabrikam

# Create Vm1.
az vm create \
  --resource-group $RgName \
  --name MyVm1 \
  --nics MyNic-Vm1 \
  --image UbuntuLTS \
  --availability-set MyAvailabilitySet \
  --admin-username azureadmin \
  --generate-ssh-keys

###### ######### VM2 ###############

# Create an Public IP for the second VM.
az network public-ip create \
  --resource-group $RgName \
  --name MyPublicIp-Vm2 \
  --allocation-method Dynamic

# Create a network interface for VM2.
az network nic create \
  --resource-group $RgName \
  --vnet-name MyVnet \
  --subnet MySubnet \
  --name MyNic-Vm2 \
  --public-ip-address MyPublicIp-Vm2

# Create IP-Configs for Contoso and Fabrikam.
az network nic ip-config create \
  --resource-group $RgName \
  --name ipconfig2 \
  --nic-name MyNic-Vm2 \
  --lb-name MyLoadBalancer \
  --lb-address-pools BeContoso
az network nic ip-config create \
  --resource-group $RgName \
  --name ipconfig3 \
  --nic-name MyNic-Vm2 \
  --lb-name MyLoadBalancer \
  --lb-address-pools BeFabrikam

# Create Vm2.
az vm create \
  --resource-group $RgName \
  --name MyVm2 \
  --nics MyNic-Vm2 \
  --image UbuntuLTS \
  --availability-set MyAvailabilitySet \
  --admin-username azureadmin \
  --generate-ssh-keys

Clean up deployment

Run the following command to remove the resource group, VM, and all related resources.

az group delete --name myResourceGroup --yes

Script explanation

This script uses the following commands to create a resource group, virtual network, load balancer, and all related resources. Each command in the table links to command specific documentation.

Command Notes
az group create Creates a resource group in which all resources are stored.
az network vnet create Creates an Azure virtual network and subnet.
az network public-ip create Creates a public IP address with a static IP address and an associated DNS name.
az network lb create Creates an Azure Load Balancer.
az network lb probe create Creates a load balancer probe. A load balancer probe is used to monitor each VM in the load balancer set. If any VM becomes inaccessible, traffic is not routed to the VM.
az network lb rule create Creates a load balancer rule. In this sample, a rule is created for port 80. As HTTP traffic arrives at the load balancer, it is routed to port 80 one of the VMs in the load balancer set.
az network lb frontend-ip create Create a frontend IP address for the Load Balancer.
az network lb address-pool create Creates a backend address pool.
az network nic create Creates a virtual network card and attaches it to the virtual network, and subnet.
az vm availability-set create Creates an availability set. Availability sets ensure application uptime by spreading the virtual machines across physical resources such that if failure occurs, the entire set is not effected.
az network nic ip-config create Creates an IP configuration. You must have the Microsoft.Network/AllowMultipleIpConfigurationsPerNic feature enabled for your subscription. Only one configuration may be designated as the primary IP configuration per NIC, using the --make-primary flag.
az vm create Creates the virtual machine and connects it to the network card, virtual network, subnet, and NSG. This command also specifies the virtual machine image to be used and administrative credentials.
az group delete Deletes a resource group including all nested resources.

Next steps

For more information on the Azure CLI, see Azure CLI documentation.