Tutorial: Deploy a linked template

In the previous tutorials, you learned how to deploy a template that is stored in your local computer. To deploy complex solutions, you can break a template into many templates, and deploy these templates through a main template. In this tutorial, you learn how to deploy a main template that contains the reference to a linked template. When the main template gets deployed, it triggers the deployment of the linked template. You also learn how to store and secure the templates by using SAS token. It takes about 12 minutes to complete.

Prerequisites

We recommend that you complete the previous tutorial, but it's not required.

Review template

In the previous tutorials, you deploy a template that creates a storage account, App Service plan, and web app. The template used was:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "projectName": {
      "type": "string",
      "minLength": 3,
      "maxLength": 11,
      "metadata": {
        "description": "Specify a project name that is used to generate resource names."
      }
    },
    "location": {
      "type": "string",
      "defaultValue": "[resourceGroup().location]",
      "metadata": {
        "description": "Specify a location for the resources."
      }
    },
    "storageSKU": {
      "type": "string",
      "defaultValue": "Standard_LRS",
      "allowedValues": [
        "Standard_LRS",
        "Standard_GRS",
        "Standard_RAGRS",
        "Standard_ZRS",
        "Premium_LRS",
        "Premium_ZRS",
        "Standard_GZRS",
        "Standard_RAGZRS"
      ],
      "metadata": {
        "description": "Specify the storage account type."
      }
    },
    "linuxFxVersion": {
      "type": "string",
      "defaultValue": "php|7.0",
      "metadata": {
        "description": "Specify the Runtime stack of current web app"
      }
    }
  },
  "variables": {
    "storageAccountName": "[concat(parameters('projectName'), uniqueString(resourceGroup().id))]",
    "webAppName": "[concat(parameters('projectName'), 'WebApp')]",
    "appServicePlanName": "[concat(parameters('projectName'), 'Plan')]"
  },
  "resources": [
    {
      "type": "Microsoft.Storage/storageAccounts",
      "apiVersion": "2021-04-01",
      "name": "[variables('storageAccountName')]",
      "location": "[parameters('location')]",
      "sku": {
        "name": "[parameters('storageSKU')]"
      },
      "kind": "StorageV2",
      "properties": {
        "supportsHttpsTrafficOnly": true
      }
    },
    {
      "type": "Microsoft.Web/serverfarms",
      "apiVersion": "2020-12-01",
      "name": "[variables('appServicePlanName')]",
      "location": "[parameters('location')]",
      "sku": {
        "name": "B1",
        "tier": "Basic",
        "size": "B1",
        "family": "B",
        "capacity": 1
      },
      "kind": "linux",
      "properties": {
        "perSiteScaling": false,
        "reserved": true,
        "targetWorkerCount": 0,
        "targetWorkerSizeId": 0
      }
    },
    {
      "type": "Microsoft.Web/sites",
      "apiVersion": "2020-12-01",
      "name": "[variables('webAppName')]",
      "location": "[parameters('location')]",
      "dependsOn": [
        "[resourceId('Microsoft.Web/serverfarms', variables('appServicePlanName'))]"
      ],
      "kind": "app",
      "properties": {
        "serverFarmId": "[resourceId('Microsoft.Web/serverfarms', variables('appServicePlanName'))]",
        "siteConfig": {
          "linuxFxVersion": "[parameters('linuxFxVersion')]"
        }
      }
    }
  ],
  "outputs": {
    "storageEndpoint": {
      "type": "object",
      "value": "[reference(variables('storageAccountName')).primaryEndpoints]"
    }
  }
}

Create a linked template

You can separate the storage account resource into a linked template:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "storageAccountName": {
      "type": "string",
      "metadata": {
        "description": "Specify the storage account name."
      }
    },
    "location": {
      "type": "string",
      "metadata": {
        "description": "Specify a location for the resources."
      }
    },
    "storageSKU": {
      "type": "string",
      "defaultValue": "Standard_LRS",
      "allowedValues": [
        "Standard_LRS",
        "Standard_GRS",
        "Standard_RAGRS",
        "Standard_ZRS",
        "Premium_LRS",
        "Premium_ZRS",
        "Standard_GZRS",
        "Standard_RAGZRS"
      ],
      "metadata": {
        "description": "Specify the storage account type."
      }
    }
  },
  "resources": [
    {
      "type": "Microsoft.Storage/storageAccounts",
      "apiVersion": "2021-04-01",
      "name": "[parameters('storageAccountName')]",
      "location": "[parameters('location')]",
      "sku": {
        "name": "[parameters('storageSKU')]"
      },
      "kind": "StorageV2",
      "properties": {
        "supportsHttpsTrafficOnly": true
      }
    }
  ],
  "outputs": {
    "storageEndpoint": {
      "type": "object",
      "value": "[reference(parameters('storageAccountName')).primaryEndpoints]"
    }
  }
}

The following template is the main template. The highlighted Microsoft.Resources/deployments object shows how to call a linked template. The linked template cannot be stored as a local file or a file that is only available on your local network. You can either provide a URI value of the linked template that includes either HTTP or HTTPS, or use the relativePath property to deploy a remote linked template at a location relative to the parent template. One option is to place both the main template and the linked template in a storage account.

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "projectName": {
      "type": "string",
      "minLength": 3,
      "maxLength": 11,
      "metadata": {
        "description": "Specify a project name that is used to generate resource names."
      }
    },
    "location": {
      "type": "string",
      "defaultValue": "[resourceGroup().location]",
      "metadata": {
        "description": "Specify a location for the resources."
      }
    },
    "linuxFxVersion": {
      "type": "string",
      "defaultValue": "php|7.0",
      "metadata": {
        "description": "The Runtime stack of current web app"
      }
    }
  },
  "variables": {
    "storageAccountName": "[concat(parameters('projectName'), uniqueString(resourceGroup().id))]",
    "webAppName": "[concat(parameters('projectName'), 'WebApp')]",
    "appServicePlanName": "[concat(parameters('projectName'), 'Plan')]"
  },
  "resources": [
    {
      "name": "linkedTemplate",
      "type": "Microsoft.Resources/deployments",
      "apiVersion": "2021-04-01",
      "properties": {
        "mode": "Incremental",
        "templateLink": {
          "relativePath": "linkedStorageAccount.json"
        },
        "parameters": {
          "storageAccountName": {
            "value": "[variables('storageAccountName')]"
          },
          "location": {
            "value": "[parameters('location')]"
          }
        }
      }
    },
    {
      "type": "Microsoft.Web/serverfarms",
      "apiVersion": "2020-12-01",
      "name": "[variables('appServicePlanName')]",
      "location": "[parameters('location')]",
      "sku": {
        "name": "B1",
        "tier": "Basic",
        "size": "B1",
        "family": "B",
        "capacity": 1
      },
      "kind": "linux",
      "properties": {
        "perSiteScaling": false,
        "reserved": true,
        "targetWorkerCount": 0,
        "targetWorkerSizeId": 0
      }
    },
    {
      "type": "Microsoft.Web/sites",
      "apiVersion": "2020-12-01",
      "name": "[variables('webAppName')]",
      "location": "[parameters('location')]",
      "dependsOn": [
        "[resourceId('Microsoft.Web/serverfarms', variables('appServicePlanName'))]"
      ],
      "kind": "app",
      "properties": {
        "serverFarmId": "[resourceId('Microsoft.Web/serverfarms', variables('appServicePlanName'))]",
        "siteConfig": {
          "linuxFxVersion": "[parameters('linuxFxVersion')]"
        }
      }
    }
  ],
  "outputs": {
    "storageEndpoint": {
      "type": "object",
      "value": "[reference('linkedTemplate').outputs.storageEndpoint.value]"
    }
  }
}

Store the linked template

Both of the main template and the linked template are stored in GitHub:

The following PowerShell script creates a storage account, creates a container, and copies the two templates from a GitHub repository to the container. These two templates are:

Select Try-it to open the Cloud Shell, select Copy to copy the PowerShell script, and right-click the shell pane to paste the script:

Important

Storage account names must be unique, between 3 and 24 characters in length, and use numbers and lowercase letters only. The sample template's storageAccountName variable combines the projectName parameter's maximum of 11 characters with a uniqueString value of 13 characters.

$projectName = Read-Host -Prompt "Enter a project name:"   # This name is used to generate names for Azure resources, such as storage account name.
$location = Read-Host -Prompt "Enter a location (i.e. centralus)"

$resourceGroupName = $projectName + "rg"
$storageAccountName = $projectName + "store"
$containerName = "templates" # The name of the Blob container to be created.

$mainTemplateURL = "https://raw.githubusercontent.com/Azure/azure-docs-json-samples/master/get-started-deployment/linked-template/azuredeploy.json"
$linkedTemplateURL = "https://raw.githubusercontent.com/Azure/azure-docs-json-samples/master/get-started-deployment/linked-template/linkedStorageAccount.json"

$mainFileName = "azuredeploy.json" # A file name used for downloading and uploading the main template.Add-PSSnapin
$linkedFileName = "linkedStorageAccount.json" # A file name used for downloading and uploading the linked template.

# Download the templates
Invoke-WebRequest -Uri $mainTemplateURL -OutFile "$home/$mainFileName"
Invoke-WebRequest -Uri $linkedTemplateURL -OutFile "$home/$linkedFileName"

# Create a resource group
New-AzResourceGroup -Name $resourceGroupName -Location $location

# Create a storage account
$storageAccount = New-AzStorageAccount `
    -ResourceGroupName $resourceGroupName `
    -Name $storageAccountName `
    -Location $location `
    -SkuName "Standard_LRS"

$context = $storageAccount.Context

# Create a container
New-AzStorageContainer -Name $containerName -Context $context -Permission Container

# Upload the templates
Set-AzStorageBlobContent `
    -Container $containerName `
    -File "$home/$mainFileName" `
    -Blob $mainFileName `
    -Context $context

Set-AzStorageBlobContent `
    -Container $containerName `
    -File "$home/$linkedFileName" `
    -Blob $linkedFileName `
    -Context $context

Write-Host "Press [ENTER] to continue ..."

Deploy template

To deploy templates in a storage account, generate a SAS token and supply it to the -QueryString parameter. Set the expiry time to allow enough time to complete the deployment. The blobs containing the templates are accessible to only the account owner. However, when you create a SAS token for a blob, the blob is accessible to anyone with that SAS token. If another user intercepts the URI and the SAS token, that user is able to access the template. A SAS token is a good way of limiting access to your templates, but you should not include sensitive data like passwords directly in the template.

If you haven't created the resource group, see Create resource group.

Note

In the below Azure CLI code, date parameter -d is an invalid argument in macOS. So macOS users, to add 2 hours to current time in terminal on macOS you should use -v+2H.


$projectName = Read-Host -Prompt "Enter the same project name:"   # This name is used to generate names for Azure resources, such as storage account name.

$resourceGroupName="${projectName}rg"
$storageAccountName="${projectName}store"
$containerName = "templates"

$key = (Get-AzStorageAccountKey -ResourceGroupName $resourceGroupName -Name $storageAccountName).Value[0]
$context = New-AzStorageContext -StorageAccountName $storageAccountName -StorageAccountKey $key

$mainTemplateUri = $context.BlobEndPoint + "$containerName/azuredeploy.json"
$sasToken = New-AzStorageContainerSASToken `
    -Context $context `
    -Container $containerName `
    -Permission r `
    -ExpiryTime (Get-Date).AddHours(2.0)
$newSas = $sasToken.substring(1)


New-AzResourceGroupDeployment `
  -Name DeployLinkedTemplate `
  -ResourceGroupName $resourceGroupName `
  -TemplateUri $mainTemplateUri `
  -QueryString $newSas `
  -projectName $projectName `
  -verbose

Write-Host "Press [ENTER] to continue ..."

Clean up resources

Clean up the resources you deployed by deleting the resource group.

  1. From the Azure portal, select Resource group from the left menu.
  2. Enter the resource group name in the Filter by name field.
  3. Select the resource group name.
  4. Select Delete resource group from the top menu.

Next steps

You learned how to deploy a linked template. In the next tutorial, you learn how to create a DevOps pipeline to deploy a template.