Exercise - Create resources using an Azure CLI script

Completed

In this unit, you continue with the example of a company that develops Linux admin tools. The goal is to use Linux virtual machines (VMs) to allow potential customers to test your software. With a resource group already set up, it's time to create the VMs.

Your company secured a booth at a large Linux trade show. You plan to set up a demo area with three terminals, each connected to a separate Linux VM. You must delete the VMs and re-create them at the end of each day so they start fresh every morning. Creating the VMs manually after a long day is error-prone, so you need to write an Azure CLI script to automate the VM creation process.

Write a script to create virtual machines

Follow these steps to write a script in Azure Cloud Shell that automates the creation of virtual machines.

Note

Usually, you'd authenticate to Azure using your credentials with az login, but in Cloud Shell, you're already authenticated, so this step is unnecessary.

1. Open Azure Cloud Shell through the Azure portal or by using the Open Cloud Shell button located in the top right corner of many Azure CLI code blocks.

2. Set your Azure subscription

   az account set --subscription "my subscription name or ID"
   

3. Using a text editor of choice, save the following script to your local drive. In this example, the file is named msdocs-script-expanded.sh.

   #!/bin/bash
   
   # Assign parameters to variables
   vmCount=$1
   resourceGroupPrefix=$2
   location=$3
   vmNamePrefix=$4
   adminUserPrefix=$5
   shift 5
   images=("$@")
   
   # Loop 
   for i in $(seq 1 $vmCount)
   do
     let "randomIdentifier=$RANDOM*$RANDOM"
     resourceGroupName=$resourceGroupPrefix-$randomIdentifier
     location=westus
     adminUserName=$adminUserPrefix-$randomIdentifier
     vmName=$vmNamePrefix-$randomIdentifier
     vmImage=${images[$((i-1)) % ${#images[@]}]}
   
     echo "Creating VM $vmName on $vmImage with admin $adminUserName in resource group $resourceGroupName"
   
     # create the resource group
     az group create --name $resourceGroupName --location $location
   
     # create the VM
     az vm create \
         --resource-group $resourceGroupName \
         --location $location \
         --name $vmName \
         --generate-ssh-keys \
         --admin-username $adminUserName \
         --image $vmImage
   
   done
   
   

4. Upload the file to your Cloud Shell drive. The easiest way is to use the Manage files menu option.

Run the script

1. Execute the script using the following command:

   #!/bin/bash
   # make your file executable
   chmod +x msdocs-script-expanded.sh
   
   # remove Windows line continuation characters
   sed -i -e 's/\r$//' msdocs-script-expanded.sh
   
   # Run the script
   ./msdocs-script-expanded.sh 3 msdocs-rg eastus2 msdocsvm msdocsadmin Debian11 Debian11 Ubuntu2204  
   

2. Wait for completion. The script takes several minutes to complete.

3. Verify the VMs. Once the script finishes, verify it completed successfully by listing the VMs in the resource group:

   az vm list -o table
   

   You should see three VMs, each with a unique name and in a separate resource group.

You successfully created a script that automates the creation of three VMs, each in a specific resource group, ensuring they're ready for daily demos at the trade show. Although the script is short and straightforward, it significantly speeds up a process that would otherwise be time-consuming and error-prone if performed manually through the Azure portal.