Most organizations don't get to choose one cloud. You've got services in Azure, maybe some workloads in AWS from an acquisition, Kubernetes running on-premises for data residency reasons. Azure Arc is Microsoft's answer to this reality. Instead of giving up on unified management, Arc projects all those resources back into Azure so you can govern them from one place. By mid-2022, the pattern is clear: if you're hybrid or multi-cloud and already invested in Azure, Arc is how you stay sane.
What Arc enables
Azure Arc projects non-Azure resources into Azure Resource Manager: on-premises servers, AWS EC2 instances, GCP VMs, and Kubernetes clusters become objects in Azure that can be managed with the same tools as native Azure resources. Azure Policy applies to Arc-enabled servers. Microsoft Defender for Cloud monitors them. The Azure portal shows them alongside Azure-native resources.
Arc for Kubernetes
Arc-enabled Kubernetes clusters, regardless of where they run, can receive GitOps configurations from Azure. A Flux configuration applied in the Azure portal deploys to on-premises clusters the same way as to AKS clusters. Azure Policy for Kubernetes applies to Arc-enabled clusters using the same Gatekeeper-based mechanism as AKS. For organisations with on-premises Kubernetes that need consistent policy enforcement across cloud and on-premises, Arc for Kubernetes is the practical solution.
Arc-enabled Data Services
Azure Arc-enabled Data Services runs Azure SQL Managed Instance and Azure PostgreSQL Hyperscale on any Kubernetes cluster. The data services are managed by Azure's control plane but run on the customer's infrastructure: on-premises hardware, a competitor's cloud, or an edge location. The pattern addresses the regulatory requirement that certain data not leave specific geographic or network boundaries while maintaining Azure management plane capabilities.
The multi-cloud management case
For CIOs with existing AWS or GCP investments alongside Azure, Arc is the Azure argument for a single management plane. The competing products (AWS Systems Manager for hybrid, GCP Anthos for multi-cloud) offer similar architectures. The decision often comes down to which cloud the organisation's primary identity and governance investment is in: Arc is the right choice when Azure AD and Azure Policy are the organisational standard.