Photo by Tadas Sar on Unsplash

Create a Virtual Machine and Attach an osDisk Snapshot using ARM Template

Azure Resource Manager (ARM)| Snapshot | Azure CLI

Have you ever had a need to replicate a Virtual Machine using an Existing Operating System (OS) Disk on Azure? Well, i know i did. So this article will explain how to do this.

Assumptions:

• Assumes you already created a Virtual Network (VNet), Network Security Groups (NSGs), and Subnet to associate to the below Virtual Machine.
• Assumes you have Azure CLI Installed
• Assumes you have the capability to run ARM Templates

Step 1. Creating the Snapshot

You can create a snapshot with easy by using the Azure CLI commands. I have written a powershell script that will do just this:

# Must already have a Virtual Machine with an OS Disk prior to running the script. 
$resourceGroup      = "<your resource group name>"
$virtualMachineName = "<your virtual machine name>"
$snapshotName       = "<name of your new snapshot>"
Write-Output "Getting OS Disk ID for Virtual Machine..."
$osDiskId = az vm list -g $resourceGroup --query "[?name == '$virtualMachineName'].storageProfile.osDisk.managedDisk.id" --output tsv
Write-Output "Creating Snapshot using OS Disk Id"
az snapshot create -g $resourceGroup -n "$snapshotName" --source $osDiskId
Write-Output "Snapshot Created"

Save the file as create-snapshot-from-disk.p1 and then run it.

Step 2. Setup an Azure Resource Manager (ARM) Template

This template will include the following resources:

• Public IP Address to access via RDP
• Network Interface
• Compute Disk
• Virtual Machine

Add the following azuredeploy.jsonc file:

{
    "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
        // Virtual Machine Instance Details
        "virtualMachineName": {
            "type": "string",
            "metadata": {…