ARM Template Structure and Syntax

ARM templates are JSON files that define Azure resources declaratively. In this lesson, you will learn the anatomy of an ARM template, understand each section, and write your first complete template.

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Template Skeleton

Every ARM template has the following top-level structure:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {},
  "variables": {},
  "functions": [],
  "resources": [],
  "outputs": {}
}

Section	Required	Description
$schema	Yes	URL of the JSON schema that validates the template
contentVersion	Yes	Version of your template (e.g., "1.0.0.0")
parameters	No	Input values provided at deployment time
variables	No	Computed values used within the template
functions	No	User-defined functions for reusable logic
resources	Yes	The Azure resources to deploy
outputs	No	Values returned after deployment

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The $schema Field

The schema URL tells ARM which template format to use. The most common schemas are:

Schema	Scope
2019-04-01/deploymentTemplate.json#	Resource group deployments
2019-08-01/managementGroupDeploymentTemplate.json#	Management group deployments
2018-05-01/subscriptionDeploymentTemplate.json#	Subscription deployments
2019-08-01/tenantDeploymentTemplate.json#	Tenant deployments

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The Resources Section

The resources array is the heart of every template. Each resource object has these properties:

{
  "type": "Microsoft.Storage/storageAccounts",
  "apiVersion": "2023-01-01",
  "name": "myuniquestorage2024",
  "location": "[resourceGroup().location]",
  "sku": {
    "name": "Standard_LRS"
  },
  "kind": "StorageV2",
  "properties": {}
}

Property	Description
type	The resource provider and type (e.g., Microsoft.Storage/storageAccounts)
apiVersion	The REST API version to use
name	The resource name (must be unique where required)
location	The Azure region
sku	The pricing tier or size
kind	The resource subtype (varies by resource)
properties	Resource-specific configuration

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A Complete Template Example

Here is a complete ARM template that deploys a storage account and a blob container: