Azure Resource Manager (ARM) - Infrastructure as Code On Azure

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August 10, 2023


In a manner that the very name subtly implies, Infrastructure as Code (IaC) revolves around the transformation of a given infrastructure into a codified entity. Within the realm of this blog, we shall embark on an exploration of the multifaceted dimensions of IaC - comprehending its essence, delving into its indispensability, and navigating the azure horizons to unearth the treasures it holds for orchestrating the IaC journey.

Infrastructure as Code constitutes the realm where infrastructure orchestration and management, think VM/EC2 VPC, converge with the world of code and configuration files. This intricate marriage empowers us to address infrastructure configuration and provisioning much akin to how we navigate the intricacies of application code. The outcome is a seamless integration of infrastructure into widely embraced version control systems, enabling the harnessing of the prowess of CI/CD pipelines with élan.

What is the need for Azure IaC?

The significance of Azure IaC emerges from the past practices of manual infrastructure management and configuration. In earlier times, each distinct environment demanded its individualized configuration, meticulously crafted by hand. This conventional approach, however, birthed a host of predicaments:

  1. Cost Implications: The necessity to engage a multitude of skilled professionals for infrastructure oversight and maintenance translated into escalated costs.
  2. Scaling Challenges: The laborious nature of manually configuring infrastructure processes rendered the process time-intensive, resulting in an arduous struggle to promptly address surges in demand.
  3. Inherent Inconsistencies: The error-prone nature of manually configuring infrastructure predisposed it to inconsistencies. Given that diverse individuals partook in these manual configurations, errors became almost inevitable.

Why Infrastructure as code on Azure?

On the contrary, Azure IaC shines due to its idempotent nature, ensuring consistent deployment outcomes across specified environments. This modern approach alleviates the need for manual intervention, thereby mitigating costs, streamlining scalability, and eradicating the specter of inconsistencies.

Infrastructure as Code (IaC) on Azure offers significant advantages for managing and deploying resources within the Azure cloud environment. Azure, a favored choice for many Fortune 500 companies, presents a wide array of services that cater to diverse business needs, spanning from storage and AI/ML to identity and access management (IAM), all unified on a single platform. Implementing IaC within Azure brings about streamlined resource management through configuration files, fostering consistency and ultimately leading to reduced errors and heightened precision.

There are two pivotal approaches to employing IaC within the Azure environment:

  1. ARM Templates: Azure Resource Manager (ARM) templates are a native IaC solution provided by Microsoft Azure. These templates are expressed in JSON format and define the desired state of resources and their relationships. This approach allows for the automated creation, updating, and deletion of Azure resources while maintaining consistency across various deployments. ARM templates are particularly suited for Azure-native services and are tightly integrated into the Azure ecosystem.
  2. Terraform: Terraform is a widely-used open-source IaC tool that supports multiple cloud providers, including Azure. It employs its own declarative language called HashiCorp Configuration Language (HCL). Terraform's strength lies in its ability to manage resources across different cloud platforms, making it suitable for organizations with multi-cloud or hybrid cloud strategies. This enables unified management of resources and deployments across various environments, including Azure.

What are ARM Templates?

Azure Resource Manager (ARM) templates are a type of infrastructure as code (IaC) used to define and deploy the infrastructure for applications on the Microsoft Azure cloud platform. These templates are written in JSON format using a declarative syntax, allowing you to specify the desired state of resources without needing to write a sequence of commands or scripts.

How Does Azure Resource Manager Work?

Azure Resource Manager centralizes the management, security, and deployment of resources in Azure. It authenticates and authorizes requests from APIs, tools, or SDKs, and then processes these requests through a unified API, ensuring consistent results. ARM templates define the resources and their properties, enabling you to deploy resources as a group, manage dependencies, and implement access control.

Benefits of IaC with ARM:

Using Azure Resource Manager for infrastructure as code offers several advantages:

  • Declarative Templates: ARM templates use declarative syntax to define the desired infrastructure state, making it easier to manage and maintain.
  • Consistency: Templates are idempotent, ensuring consistent deployment results across environments.
  • Orchestration: ARM manages the deployment order of interdependent resources, simplifying complex deployments.
  • Modularity: Templates can be broken down into reusable components, enhancing organization and maintainability.
  • Extensibility: Scripts can be integrated into templates, allowing additional customizations during deployment.
  • Validation and Tracking: ARM provides built-in validation and tracks deployment history for easy troubleshooting.

Template Limits: ARM templates have some limitations:

  • Maximum template size: 4 MB
  • Maximum parameters: 256
  • Maximum variables: 256
  • Maximum resources (including copy count): 800
  • Maximum output values: 64
  • Maximum characters in a template expression: 24,576

Resource Groups:

Resource groups should be created in the same region as resources. If a resource group deployed in a different region is unavailable, updates to resources within it will be affected.

API Version:

Set the API version property for resource types in templates. Using the latest version during template creation is recommended, and consistency with the version is advised to avoid issues.

Use of Test Toolkit:

A test toolkit can be used to validate templates against best practices. It provides warnings and suggestions for template improvements.

How to Utilize Terraform with Azure?

Following Azure Resource Manager templates, Terraform stands out as the second most popular approach for implementing and adhering to Infrastructure as Code (IaC) principles within the Azure environment. Developed by HashiCorp, Terraform is a widely used open-source tool designed for automating infrastructure tasks. It functions as a versatile solution, applicable across various cloud providers like Azure, AWS, and GCP, employing a uniform workflow. By allowing the definition of infrastructure elements such as virtual machines, storage, and other Azure resources through configuration files, Terraform facilitates the configuration, provisioning, and management of infrastructure as code. One of its key advantages is its ability to provide a consistent set of tools for managing infrastructure across diverse cloud platforms.

Advantages of Implementing IaC on Azure using Terraform:

  • Automated Infrastructure Management: Terraform empowers users to craft, provision, and modify resources using configuration files rooted in templates. This automation streamlines the management of infrastructure components.
  • Cross-Cloud Automation Agnostic to Platforms: Among the full-featured automation solutions available, Terraform uniquely transcends specific platforms, enabling automation not only within cloud environments but also across on-premises systems. Given the prevalence of multi-cloud strategies, this feature becomes particularly advantageous.
  • Enhanced Understanding of Infrastructure Changes: Terraform's capabilities extend to both configuration and documentation, enabling the creation of detailed plans. These plans serve as a guide to comprehending the intricacies of your infrastructure's configuration and anticipating the potential impacts of proposed modifications.
  • By integrating Terraform into your Azure workflow, you can harness the benefits of automated infrastructure management, platform-agnostic automation, and a clearer grasp of the implications of infrastructure adjustments.


Infrastructure as Code (IaC) involves expressing and overseeing infrastructure through code, promoting both consistency and efficiency. Moreover, Azure stands out as a prominent and trustworthy public Cloud Service Provider (CSP) for IaC adoption, owing to its utilization of native ARM templates and its ability to seamlessly integrate with open-source tools such as Terraform.

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