Azure Resource Manager templates

In an earlier section, we witnessed deployment features such as multi-service, multi-region, extensible, and idempotent provided by the ARM. ARM templates are primary means of provisioning resources in the ARM. ARM templates provide implementation support for ARM deployment features.

ARM templates provide a declarative model through which resources, their configuration, scripts, and extensions are specified. ARM templates are based on JavaScript Object Notation (JSON) format. They use the JSON syntax and conventions to declare and configure resources. JSON files are text-based, human-friendly, and easily readable files.

They can be stored in a source code repository and have version control. They are also a means to represent IAC that can be used to provision resources in an Azure resource group again and again, predictably, consistently, and uniformly. A template needs a resource group for deployment. It can only be deployed to a resource group and the resource group should exist before executing a template deployment. A template is not capable of creating a resource group.

Templates provide the flexibility to be generic and modular in their design and implementation. Templates provide the ability to accept parameters from users, declare internal variables, help in defining dependencies between resources, link resources within same or different resource groups, and execute other templates. They also provide scripting language type expressions and functions that make them dynamic and customizable at runtime.