Azure Hybrid Cloud Architecture

The Azure Hybrid Cloud architecture provides a unified, secure, and scalable foundation for extending on‑premises environments to the Azure public cloud. It enables consistent management, governance, and security across both realms.

Core Concepts

Unified Identity: Azure Active Directory (Azure AD) connects on‑premises AD with cloud services.
Hybrid Connectivity: ExpressRoute and VPN gateways ensure low‑latency, private connections.
Consistent Management: Azure Arc brings Azure management to any infrastructure.
Secure Data Flow: Azure Firewall, DDoS Protection, and encryption at rest/in‑flight.

Reference Architecture

Key Components

Component	Purpose
Azure Arc	Brings Azure services and governance to on‑premises and multi‑cloud.
Azure Site Recovery	Disaster recovery and workload replication.
Azure Stack Hub	Runs Azure services in your datacenter.
Azure ExpressRoute	Dedicated private connection between your network and Azure.
Azure Virtual WAN	Unified network and security management.

Network Topology

{
  "onPrem": {
    "subnets": ["10.0.0.0/24","10.0.1.0/24"],
    "gateway": "VPN"
  },
  "azure": {
    "vnet": "10.1.0.0/16",
    "subnets": ["10.1.0.0/24","10.1.1.0/24"],
    "expressRoute": true
  },
  "connectivity": "Site‑to‑Site VPN + ExpressRoute"
}

Security Model

Security is built in layers:

Identity – Azure AD Conditional Access.
Network – Azure Firewall, Network Security Groups.
Data – Azure Key Vault, Transparent Data Encryption.
Compliance – Azure Policy and Blueprints.

Deployment Options

Lift‑and‑Shift: Migrate VMs with Azure Migrate.
Refactor: Re‑architect workloads using Azure Kubernetes Service (AKS).
Hybrid Apps: Deploy parts of the app in Azure while keeping critical data on‑premises.

Microsoft Docs