Introduction to Infrastructure as Code (IaC)

What is Infrastructure as Code (IaC)?

IaC is the practice of defining and managing your infrastructure (like servers, databases, networks, etc.) using code that can be versioned, reviewed, and deployed through DevOps pipelines. It replaces manual configurations with repeatable, scalable, and automated processes.

• Ensures consistency across environments like Dev, QA, and Production
• Automates deployment and reduces human errors
• Speeds up disaster recovery and scaling operations
• Reduces configuration drift and makes changes auditable

Types of IaC Approaches

There are two main approaches to defining infrastructure as code:

• Declarative IaC: You describe the desired state, and the tool figures out how to reach it (e.g., Terraform, ARM Templates).
• Imperative IaC: You specify the exact steps to take in sequence (e.g., Ansible, PowerShell DSC).

Why Use Infrastructure as Code?

• Version Control: Track and manage infrastructure like application code in Git or Azure Repos
• Automation: Speed up deployments and reduce manual intervention through CI/CD
• Reproducibility: Easily replicate environments across teams and stages
• Security and Compliance: Apply standardized configurations and security settings every time

How to Implement IaC with Azure DevOps

To get started with IaC in Azure DevOps, follow this step-by-step workflow:

1. Define Infrastructure: Write configuration files using tools like Terraform, Bicep, or ARM Templates.
2. Store the Code: Push the configuration files to a source control system like Azure Repos or GitHub.
3. Configure Pipelines: Use Azure Pipelines to automate the deployment of infrastructure changes.
4. Monitor & Maintain: Observe changes, apply updates, and validate configurations regularly.

Sample YAML: Deploying Terraform using Azure DevOps

stages:
- stage: DeployInfrastructure
  displayName: 'Deploy Infrastructure as Code'
  jobs:
  - job: TerraformApply
    steps:
    - task: TerraformTaskV2
      inputs:
        provider: 'azurerm'
        command: 'apply'
        workingDirectory: '$(Build.SourcesDirectory)/infra'
        

This snippet uses a Terraform task to provision Azure infrastructure in a pipeline.

Best Practices for Using IaC

• Break your infrastructure into modular templates for reusability
• Always use code reviews and approvals for infrastructure changes
• Use RBAC (Role-Based Access Control) to protect sensitive environments
• Run validation tests for syntax and logic before deployment
• Implement state management and locking (e.g., Terraform state files) to avoid conflicts

Conclusion

Infrastructure as Code empowers development and operations teams to manage infrastructure with the same discipline as application code. With Azure DevOps, you can build consistent, secure, and scalable environments faster — and deploy with confidence.

Up next, we'll compare ARM Templates vs Terraform to help you decide which IaC tool best fits your needs.