Azure CLI script example: Load balance traffic to VMs within a specific availability zone
This Azure CLI script example creates everything needed to run several Ubuntu virtual machines configured in a highly available and load balanced configuration within a specific availability zone. After running the script, you will have three virtual machines in a single availability zones within a region that are accessible through an Azure Standard Load Balancer.
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 subscription, create an Azure free account before you begin.
Sample script
#!/bin/bash
# Create a resource group.
az group create \
--name myResourceGroup \
--location westeurope
# Create a virtual network.
az network vnet create \
--resource-group myResourceGroup \
--location westeurope \
--name myVnet \
--subnet-name mySubnet
# Create a zonal Standard public IP address.
az network public-ip create \
--resource-group myResourceGroup \
--name myPublicIP \
--sku Standard
--zone 1
# Create an Azure Load Balancer.
az network lb create \
--resource-group myResourceGroup \
--name myLoadBalancer \
--public-ip-address myPublicIP \
--frontend-ip-name myFrontEndPool \
--backend-pool-name myBackEndPool \
--sku Standard
# Creates an LB probe on port 80.
az network lb probe create \
--resource-group myResourceGroup \
--lb-name myLoadBalancer \
--name myHealthProbe \
--protocol tcp \
--port 80
# Creates an LB rule for port 80.
az network lb rule create \
--resource-group myResourceGroup \
--lb-name myLoadBalancer \
--name myLoadBalancerRuleWeb \
--protocol tcp \
--frontend-port 80 \
--backend-port 80 \
--frontend-ip-name myFrontEndPool \
--backend-pool-name myBackEndPool \
--probe-name myHealthProbe
# Create three NAT rules for port 22.
for i in `seq 1 3`; do
az network lb inbound-nat-rule create \
--resource-group myResourceGroup \
--lb-name myLoadBalancer \
--name myLoadBalancerRuleSSH$i \
--protocol tcp \
--frontend-port 422$i \
--backend-port 22 \
--frontend-ip-name myFrontEndPool
done
# Create a network security group
az network nsg create \
--resource-group myResourceGroup \
--name myNetworkSecurityGroup
# Create a network security group rule for port 22.
az network nsg rule create \
--resource-group myResourceGroup \
--nsg-name myNetworkSecurityGroup \
--name myNetworkSecurityGroupRuleSSH \
--protocol tcp \
--direction inbound \
--source-address-prefix '*' \
--source-port-range '*' \
--destination-address-prefix '*' \
--destination-port-range 22 \
--access allow \
--priority 1000
# Create a network security group rule for port 80.
az network nsg rule create \
--resource-group myResourceGroup \
--nsg-name myNetworkSecurityGroup \
--name myNetworkSecurityGroupRuleHTTP \
--protocol tcp \
--direction inbound \
--source-address-prefix '*' \
--source-port-range '*' \
--destination-address-prefix '*' \
--destination-port-range 80 \
--access allow \
--priority 2000
# Create three virtual network cards and associate with public IP address and NSG.
for i in `seq 1 3`; do
az network nic create \
--resource-group myResourceGroup \
--name myNic$i \
--vnet-name myVnet \
--subnet mySubnet \
--network-security-group myNetworkSecurityGroup \
--lb-name myLoadBalancer \
--lb-address-pools myBackEndPool \
--lb-inbound-nat-rules myLoadBalancerRuleSSH$i
done
# Create three virtual machines, this creates SSH keys if not present.
for i in `seq 1 3`; do
az vm create \
--resource-group myResourceGroup \
--name myVM$i \
--zone 1 \
--nics myNic$i \
--image UbuntuLTS \
--generate-ssh-keys \
--no-wait
done
Clean up deployment
Run the following command to remove the resource group, VM, and all related resources.
az group delete --name myResourceGroup
Script explanation
This script uses the following commands to create a resource group, virtual machine, availability set, 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 LB set. |
| az network lb inbound-nat-rule create | Creates load balancer Network Address Translation (NAT) rule. NAT rules map a port of the load balancer to a port on a VM. In this sample, a NAT rule is created for SSH traffic to each VM in the load balancer set. |
| az network nsg create | Creates a network security group (NSG), which is a security boundary between the internet and the virtual machine. |
| az network nsg rule create | Creates an NSG rule to allow inbound traffic. In this sample, port 22 is opened for SSH traffic. |
| az network nic create | Creates a virtual network card and attaches it to the virtual network, subnet, and NSG. |
| 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.
Additional Azure Networking CLI script samples can be found in the Azure Networking documentation.