Infrastructure as Code: ARM, Bicep, and Arc | Guided by A Guide to Cloud

Infrastructure as Code — why it matters

Simple explanation

Imagine building IKEA furniture.

You could build it from memory — but every time, you’d forget a step and the bookshelf would wobble. Or you could follow the instruction manual — identical bookshelf every time.

Infrastructure as Code (IaC) is the instruction manual for your cloud. Instead of clicking through the Azure portal to create resources, you write a file that describes exactly what you want. Then you “deploy” the file, and Azure builds it perfectly — every time.

ARM templates and Bicep are Azure’s IaC languages.

Azure Arc extends Azure management to resources running elsewhere — on-premises servers, other clouds, or edge locations. One control plane to rule them all.

Azure Resource Manager (ARM)

ARM is the management layer that handles all requests to Azure:

Azure Portal ──→ ARM ──→ Azure Resources
Azure CLI    ──→ ARM ──→ Azure Resources
PowerShell   ──→ ARM ──→ Azure Resources
REST API     ──→ ARM ──→ Azure Resources
ARM Template ──→ ARM ──→ Azure Resources

No matter how you interact with Azure, ARM processes the request. This ensures:

Consistent behaviour across all tools
Access control (RBAC is enforced at the ARM layer)
Tagging and resource organisation
Dependency management between resources

ARM templates and Bicep

ARM templates (JSON)

ARM templates are JSON files that define your infrastructure:

Benefit	Description
Declarative	You describe WHAT you want, not HOW to create it
Repeatable	Deploy the same template in dev, test, and production
Idempotent	Deploy the same template twice = no duplicate resources
Version controlled	Store in Git, track changes, review before deploying
Orchestrated	ARM handles dependencies (create the VNet before the VM)

Bicep — cleaner IaC

Bicep is a simpler language that compiles to ARM template JSON. Think of Bicep as the human-friendly version of ARM templates:

Aspect	ARM Template (JSON)	Bicep
Syntax	Verbose JSON	Clean, concise
Learning curve	Steeper	Easier
File extension	.json	.bicep
Capabilities	Full Azure support	Same (compiles to JSON)

Exam scope: AZ-900 tests whether you understand the PURPOSE and benefits of IaC, ARM, and Bicep — not the syntax details. Know that Bicep is simpler than JSON ARM templates but produces the same results.

Declarative vs imperative

IaC can be declarative or imperative:

Declarative (ARM templates, Bicep, Terraform): “I want 2 VMs, a VNet, and a database.” The tool figures out how to create them.
Imperative (CLI scripts, PowerShell): “Step 1: Create VNet. Step 2: Create VM-1. Step 3: Create VM-2. Step 4: Create database.”

ARM templates and Bicep are declarative — you define the desired state, and Azure makes it happen.

Azure Arc — manage beyond Azure

Azure Arc extends Azure management to resources outside Azure:

What It Manages	Where It Runs	Example
Arc-enabled servers	On-premises, AWS, GCP	Apply Azure Policy to an on-prem Windows server
Arc-enabled Kubernetes	Any Kubernetes cluster	Manage an on-prem K8s cluster from Azure portal
Arc-enabled data services	On-premises, edge	Run Azure SQL Managed Instance on your own hardware

Why Arc matters:

Single control plane — manage Azure and non-Azure resources from the Azure portal
Consistent governance — apply Azure Policy to servers running anywhere
Unified monitoring — use Azure Monitor for on-prem and cloud resources

Summit Construction uses Azure Arc to manage the Windows servers still running in their office. From the Azure portal, they can view health, apply policies, and monitor performance — even though those servers aren’t in Azure.

Exam tip: Azure Arc scenarios

If a question mentions managing resources in multiple clouds or on-premises through Azure, the answer is Azure Arc. Key phrases:

“Manage on-premises servers from Azure”
“Apply Azure Policy to non-Azure resources”
“Single management plane across hybrid environments”

🎬 Video walkthrough

🎬 Video coming soon

Infrastructure as Code — AZ-900

~9 min

Flashcards

Question

What is Infrastructure as Code (IaC)?

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Answer

Managing infrastructure through machine-readable files instead of manual configuration. Benefits: consistency, repeatability, version control, and automation. ARM templates and Bicep are Azure's IaC tools.

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Question

What is Azure Resource Manager (ARM)?

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Answer

The management layer that processes ALL Azure requests — whether from the portal, CLI, PowerShell, API, or templates. ARM enforces RBAC, manages dependencies, and ensures consistent behaviour.

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Question

How does Bicep relate to ARM templates?

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Answer

Bicep is a simpler, cleaner language that COMPILES to ARM template JSON. Same capabilities, easier syntax. Bicep files (.bicep) are converted to ARM templates (.json) before deployment.

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Question

What is Azure Arc?

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Answer

Extends Azure management and governance to non-Azure resources — on-premises servers, Kubernetes clusters, and multi-cloud resources. Provides a single control plane in the Azure portal.

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Knowledge Check

Summit Construction wants to deploy identical environments for each new project — same VMs, networking, and database every time. What approach ensures consistency?

Knowledge Check

Harbour Health has servers in Azure AND in their on-premises datacenter. They want to manage both from a single Azure portal experience. Which service enables this?

Next up: Azure Advisor and Service Health — your cloud consultant and health dashboard.