Tutorial: Create multiple resource instances with ARM templates

Article
06/20/2024

Learn how to iterate in your Azure Resource Manager template (ARM template) to create multiple instances of an Azure resource. In this tutorial, you modify a template to create three storage account instances.

Diagram showing Azure Resource Manager creating multiple instances.

This tutorial covers the following tasks:

Open a Quickstart template
Edit the template
Deploy the template

If you don't have an Azure subscription, create a free account before you begin.

For a Learn module that covers resource copy, see Manage complex cloud deployments by using advanced ARM template features.

Prerequisites

To complete this article, you need:

Visual Studio Code with Resource Manager Tools extension. See Quickstart: Create ARM templates with Visual Studio Code.

Open a Quickstart template

Azure Quickstart Templates is a repository for ARM templates. Instead of creating a template from scratch, you can find a sample template and customize it. The template used in this quickstart is called Create a standard storage account. The template defines an Azure Storage account resource.

From Visual Studio Code, select File > Open File.

In File name, paste the following URL:

https://raw.githubusercontent.com/Azure/azure-quickstart-templates/master/quickstarts/microsoft.storage/storage-account-create/azuredeploy.json

Select Open to open the file.
There's a Microsoft.Storage/storageAccounts resource defined in the template. Compare the template to the template reference. It's helpful to get some basic understanding of the template before customizing it.
Select File > Save As to save the file as azuredeploy.json to your local computer.

Edit the template

The existing template creates one storage account. You customize the template to create three storage accounts.

From Visual Studio Code, make the following four changes:

Screenshot of Visual Studio Code with Azure Resource Manager creating multiple instances.

Add a copy element to the storage account resource definition. In the copy element, you specify the number of iterations and a variable for this loop. The count value must be a positive integer and can't exceed 800.
```
"copy": {
  "name": "storageCopy",
  "count": 3
},
```
The copyIndex() function returns the current iteration in the loop. You use the index as the name prefix. copyIndex() is zero-based. To offset the index value, you can pass a value in the copyIndex() function. For example, copyIndex(1).
```
"name": "[format('{0}storage{1}', copyIndex(), uniqueString(resourceGroup().id))]",
```
Delete the storageAccountName parameter definition, because it's not used anymore.
Delete the outputs element. It's no longer needed.
Delete the metadata element.

The completed template looks like:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "storageAccountType": {
      "type": "string",
      "defaultValue": "Standard_LRS",
      "allowedValues": [
        "Premium_LRS",
        "Premium_ZRS",
        "Standard_GRS",
        "Standard_GZRS",
        "Standard_LRS",
        "Standard_RAGRS",
        "Standard_RAGZRS",
        "Standard_ZRS"
      ],
      "metadata": {
        "description": "Storage Account type"
      }
    },
    "location": {
      "type": "string",
      "defaultValue": "[resourceGroup().location]",
      "metadata": {
        "description": "Location for the storage account."
      }
    }
  },
  "resources": [
    {
      "type": "Microsoft.Storage/storageAccounts",
      "apiVersion": "2021-06-01",
      "name": "[format('{0}storage{1}', copyIndex(), uniqueString(resourceGroup().id))]",
      "location": "[parameters('location')]",
      "sku": {
        "name": "[parameters('storageAccountType')]"
      },
      "kind": "StorageV2",
      "copy": {
        "name": "storageCopy",
        "count": 3
      },
      "properties": {}
    }
  ]
}

Save the changes.

For more information about creating multiple instances, see Resource iteration in ARM templates

Deploy the template

Sign in to the Azure Cloud Shell
Choose your preferred environment by selecting either PowerShell or Bash (for CLI) on the upper left corner. Restarting the shell is required when you switch.
Select Upload/download files, and then select Upload. See the previous screenshot. Select the file you saved in the previous section. After uploading the file, you can use the ls command and the cat command to verify the file was uploaded successfully.

From the Cloud Shell, run the following commands. Select the tab to show the PowerShell code or the CLI code.

CLI
PowerShell

echo "Enter a project name that is used to generate resource group name:" &&
read projectName &&
echo "Enter the location (i.e. centralus):" &&
read location &&
resourceGroupName="${projectName}rg" &&
az group create --name $resourceGroupName --location "$location" &&
az deployment group create --resource-group $resourceGroupName --template-file "$HOME/azuredeploy.json"

$projectName = Read-Host -Prompt "Enter a project name that is used to generate resource group name"
$location = Read-Host -Prompt "Enter the location (i.e. centralus)"
$resourceGroupName = "${projectName}rg"

New-AzResourceGroup -Name $resourceGroupName -Location "$location"
New-AzResourceGroupDeployment -ResourceGroupName $resourceGroupName -TemplateFile "$HOME/azuredeploy.json"

After a successful template deployment, you can display the three storage accounts created in the specified resource group. Compare the storage account names with the name definition in the template.

CLI
PowerShell

echo "Enter a project name that is used to generate resource group name:" &&
read projectName &&
resourceGroupName="${projectName}rg" &&
az storage account list --resource-group $resourceGroupName &&
echo "Press [ENTER] to continue ..."

$projectName = Read-Host -Prompt "Enter a project name that is used to generate resource group name"
$resourceGroupName = "${projectName}rg"

Get-AzStorageAccount -ResourceGroupName $resourceGroupName
Write-Host "Press [ENTER] to continue ..."

Clean up resources

When the Azure resources are no longer needed, clean up the resources you deployed by deleting the resource group.

From the Azure portal, select Resource group from the left menu.
Enter the resource group name in the Filter by name field.
Select the resource group name. You shall see a total of three resources in the resource group.
Select Delete resource group from the top menu.

Next steps

In this tutorial, you learned how to create multiple storage account instances. In the next tutorial, you develop a template with multiple resources and multiple resource types. Some of the resources have dependent resources.

Create dependent resources

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