Azure Resource Manager overview

1. Azure Resource Manager is the deployment and management service for Azure. It provides a consistent management layer that enables you to create, update, and delete resources in your Azure subscription. You can use its access control, auditing, and tagging features to secure and organize your resources after deployment.

2. When you take actions through the portal, PowerShell, Azure CLI, REST APIs, or client SDKs, the Azure Resource Manager API handles your request. Because all requests are handled through the same API, you see consistent results and capabilities in all the different tools. All capabilities that are available in the portal are also available through PowerShell, Azure CLI, REST APIs, and client SDKs. Functionality initially released through APIs will be represented in the portal within 180 days of initial release.

3. The following image shows how all the tools interact with the Azure Resource Manager API. The API passes requests to the Resource Manager service, which authenticates and authorizes the requests. Resource Manager then routes the requests to the appropriate service.

Terminology

If you're new to Azure Resource Manager, there are some terms you might not be familiar with.

• resource - A manageable item that is available through Azure. Virtual machines, storage accounts, web apps, databases, and virtual networks are examples of resources.
• resource group - A container that holds related resources for an Azure solution. The resource group includes those resources that you want to manage as a group. You decide how to allocate resources to resource groups based on what makes the most sense for your organization.
• resource provider - A service that supplies Azure resources. For example, a common resource provider is Microsoft.Compute, which supplies the virtual machine resource. Microsoft.Storage is another common resource provider. 
• Resource Manager template - A JavaScript Object Notation (JSON) file that defines one or more resources to deploy to a resource group or subscription. The template can be used to deploy the resources consistently and repeatedly. 
• declarative syntax - Syntax that lets you state "Here is what I intend to create" without having to write the sequence of programming commands to create it. The Resource Manager template is an example of declarative syntax. In the file, you define the properties for the infrastructure to deploy to Azure.

What are benefits of using Resource Manager

Resource Manager provides several benefits:

• You can deploy, manage, and monitor all the resources for your solution as a group, rather than handling these resources individually.
• You can repeatedly deploy your solution throughout the development lifecycle and have confidence your resources are deployed in a consistent state.
• You can manage your infrastructure through declarative templates rather than scripts.
• You can define the dependencies between resources so they're deployed in the correct order.
• You can apply access control to all services in your resource group because Role-Based Access Control (RBAC) is natively integrated into the management platform.
• You can apply tags to resources to logically organize all the resources in your subscription.
• You can clarify your organization's billing by viewing costs for a group of resources sharing the same tag.

Understand scope

Azure provides four levels of scope: 

1. Management groups

2.  Subscriptions

3.  Resource groups

4. Resources. 

The following image shows an example of these layers.

 You apply management settings at any of these levels of scope. The level you select determines how widely the setting is applied. Lower levels inherit settings from higher levels. For example, when you apply a policy to the subscription, the policy is applied to all resource groups and resources in your subscription. When you apply a policy on the resource group, that policy is applied the resource group and all its resources. However, another resource group doesn't have that policy assignment.

You can deploy templates to management groups, subscriptions, or resource groups.

Point to be remember

• Define and deploy your infrastructure through the declarative syntax in Resource Manager templates, rather than through imperative commands.
• Define all deployment and configuration steps in the template. You should have no manual steps for setting up your solution.
• Run imperative commands to manage your resources, such as to start or stop an app or machine.
• Arrange resources with the same lifecycle in a resource group. Use tags for all other organizing of resources.

Resource groups

There are some important factors to consider when defining your resource group:

• All the resources in your group should share the same lifecycle. You deploy, update, and delete them together. If one resource, such as a database server, needs to exist on a different deployment cycle it should be in another resource group.
• Each resource can only exist in one resource group.
• You can add or remove a resource to a resource group at any time.
• You can move a resource from one resource group to another group. For more information.
• A resource group can contain resources that are located in different regions.
• A resource group can be used to scope access control for administrative actions.
• A resource can interact with resources in other resource groups. This interaction is common when the two resources are related but don't share the same lifecycle (for example, web apps connecting to a database).

Resource providers

Each resource provider offers a set of resources and operations for working with those resources. For example, if you want to store keys and secrets, you work with the Microsoft.KeyVault resource provider. This resource provider offers a resource type called vaults for creating the key vault.

The name of a resource type is in the format: {resource-provider}/{resource-type}. The resource type for a key vault is Microsoft.KeyVault/vaults.

Before getting started with deploying your resources, you should gain an understanding of the available resource providers. Knowing the names of resource providers and resources helps you define resources you want to deploy to Azure. Also, you need to know the valid locations and API versions for each resource type.

Template deployment

With Resource Manager, you can create a template (in JSON format) that defines the infrastructure and configuration of your Azure solution. By using a template, you can repeatedly deploy your solution throughout its lifecycle and have confidence your resources are deployed in a consistent state.

To learn about the format of the template and how you construct it, see Understand the structure and syntax of Azure Resource Manager Templates. To view the JSON syntax for resources types, see Define resources in Azure Resource Manager templates.

Resource Manager processes the template like any other request. It parses the template and converts its syntax into REST API operations for the appropriate resource providers. For example, when Resource Manager receives a template with the following resource definition:

JSON

"resources": [
  {
    "apiVersion": "2016-01-01",
    "type": "Microsoft.Storage/storageAccounts",
    "name": "mystorageaccount",
    "location": "westus",
    "sku": {
      "name": "Standard_LRS"
    },
    "kind": "Storage",
    "properties": {
    }
  }
]

It converts the definition to the following REST API operation, which is sent to the Microsoft.Storage resource provider:

https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Storage/storageAccounts/mystorageaccount?api-version=2016-01-01

REQUEST BODY
{
  "location": "westus",
  "properties": {
  }
  "sku": {
    "name": "Standard_LRS"
  },
  "kind": "Storage"
}

How you define templates and resource groups is entirely up to you and how you want to manage your solution. For example, you can deploy your three tier application through a single template to a single resource group.

But, you don't have to define your entire infrastructure in a single template. Often, it makes sense to divide your deployment requirements into a set of targeted, purpose-specific templates. You can easily reuse these templates for different solutions. To deploy a particular solution, you create a master template that links all the required templates. The following image shows how to deploy a three tier solution through a parent template that includes three nested templates.

If you envision your tiers having separate lifecycles, you can deploy your three tiers to separate resource groups. Notice the resources can still be linked to resources in other resource groups.