What is Azure Arc?
Azure Arc is a set of technologies that extends Azure management, governance, and services to any infrastructure — whether it's running on-premises in your own data centre, on another cloud provider like AWS or GCP, or at the edge.
With Azure Arc, a Linux server sitting in your Mumbai office appears in the Azure Portal just like an Azure VM. You can apply Azure Policies to it, monitor it with Azure Monitor, secure it with Microsoft Defender — even if it never moves to Azure.
The Problem Azure Arc Solves
Consider a typical enterprise that has:
- 50 on-premises Windows and Linux servers in their Chennai data centre
- A Kubernetes cluster running on AWS EKS
- Some VMs on Azure
- Edge devices in retail stores
Without Arc, managing these requires four separate consoles, four sets of policies, four monitoring dashboards, and four different ways to apply security. Teams use different tools, policies drift, and security gaps appear.
With Arc, all of these appear in the Azure Portal. One set of policies. One monitoring view. One security baseline. One place to manage access control.
How Azure Arc Works
Azure Arc works by installing a lightweight agent on the machine you want to manage — called the Azure Connected Machine agent (for servers) or the Arc-enabled Kubernetes agent.
Once installed, the agent:
- Registers the machine with Azure Resource Manager
- Makes the machine appear as an Azure resource in the portal
- Allows Azure policies, tags, RBAC, and monitoring to be applied to it
- Reports health and compliance status back to Azure
Arc-Enabled Servers
Azure Arc-enabled Servers lets you manage physical and virtual machines running Windows or Linux — anywhere — through the Azure Portal, just as if they were Azure VMs.
What You Can Do with Arc-Enabled Servers
- Apply Azure Policies — Enforce configuration standards (e.g., "All servers must have the monitoring agent installed")
- Use Azure Monitor — Collect logs and metrics from on-premises servers in the same Azure Monitor workspace as your Azure VMs
- Microsoft Defender for Servers — Get threat detection and security recommendations on non-Azure servers
- Azure Automation — Run update management and inventory tracking on on-premises servers
- Tags and RBAC — Tag on-premises servers and control who manages them using Azure RBAC
Arc-Enabled Kubernetes
Azure Arc-enabled Kubernetes lets you attach any Kubernetes cluster — running on-premises, on AWS EKS, on Google GKE, or anywhere else — to Azure. Once attached, you can manage and govern it from the Azure Portal.
What You Can Do
- View cluster health and inventory in the Azure Portal
- Deploy applications to the cluster using GitOps (Flux)
- Apply Azure Policies to enforce cluster configuration standards
- Monitor with Azure Monitor for containers
- Use Microsoft Defender for Kubernetes threat protection
Arc-Enabled Data Services
Azure Arc-enabled Data Services lets you run Azure data services — specifically Azure SQL Managed Instance and PostgreSQL — on any infrastructure, while still being managed like Azure services.
This means you can run Azure SQL Managed Instance on your on-premises servers and get:
- Automatic updates and patching (Microsoft manages the data service layer)
- Elastic scale — add or remove vCores without downtime
- Built-in high availability
- Azure data security features
Governance with Azure Arc
One of Arc's biggest value propositions is applying Azure's governance tools to non-Azure resources:
| Azure Governance Tool | Works on Arc Resources? | What It Does |
|---|---|---|
| Azure Policy | ✅ Yes | Enforce configuration standards on any Arc resource |
| Azure RBAC | ✅ Yes | Control who can manage Arc resources |
| Azure Tags | ✅ Yes | Organise and track costs for non-Azure resources |
| Azure Monitor | ✅ Yes | Collect logs and metrics from anywhere |
| Microsoft Defender | ✅ Yes | Security monitoring and threat detection |
| Azure Update Manager | ✅ Yes | Patch management for on-premises servers |
When to Use Azure Arc
| Scenario | Use Arc? | Why |
|---|---|---|
| On-premises servers you can't migrate | ✅ Yes | Bring Azure governance to servers that must stay on-prem |
| Kubernetes clusters on AWS/GCP | ✅ Yes | Manage multi-cloud K8s from one place |
| Hybrid cloud strategy | ✅ Yes | Consistent governance across cloud and on-prem |
| All resources already in Azure | ❌ Not needed | Azure-native resources are already managed by Azure |
| Edge devices and IoT | ✅ Yes | Arc can manage edge devices like retail kiosks or factory machines |
Azure Arc vs Azure Stack
These are two different Microsoft products for hybrid cloud — they're often confused:
| Azure Arc | Azure Stack Hub | |
|---|---|---|
| What it is | Management layer for non-Azure resources | Azure infrastructure running in your data centre |
| Requires Azure hardware? | No — works with any server | Yes — specific Microsoft-validated hardware |
| Runs Azure services locally? | No — management only | Yes — actual Azure VMs, App Service, etc. run on-prem |
| Best for | Governance of existing on-prem and multi-cloud resources | Full Azure IaaS/PaaS capabilities in disconnected environments |
| Cost | Pay per managed resource | Significant hardware investment |