Azure Architecture Reference

Comprehensive guide for Azure services, patterns, and Cloud Adoption Framework implementation.

Cloud Adoption Framework

Framework Phases

1. Strategy

   • Define business justification
   • Expected business outcomes
   • Business case development
   • First project prioritization

2. Plan

   • Digital estate assessment
   • Initial organization alignment
   • Skills readiness plan
   • Cloud adoption plan

3. Ready

   • Azure landing zone setup
   • Azure setup guide
   • Migration readiness
   • Best practices validation

4. Adopt (Migrate + Innovate)

   • Migration: Assess, migrate, optimize
   • Innovate: Build cloud-native solutions
   • Best practices and patterns

5. Govern

   • Methodology for governance
   • Governance benchmark
   • Initial governance foundation
   • Mature governance evolution

6. Manage

   • Business commitments
   • Operations baseline
   • Platform and workload specialization

Azure Well-Architected Framework

Five Pillars

1. Cost Optimization

   • Azure Cost Management and Billing
   • Reserved instances and Savings Plans
   • Azure Hybrid Benefit
   • Auto-scaling and right-sizing

2. Operational Excellence

   • Infrastructure as Code (ARM, Bicep, Terraform)
   • Azure DevOps and GitHub Actions
   • Azure Monitor and Application Insights
   • Deployment slots and blue-green deployments

3. Performance Efficiency

   • Azure CDN and Front Door
   • Auto-scaling (VMSS, App Service)
   • Caching (Redis, CDN)
   • Performance diagnostics

4. Reliability

   • Availability Zones and regions
   • Azure Site Recovery
   • Load Balancer and Traffic Manager
   • Backup and disaster recovery

5. Security

   • Azure AD (Entra ID)
   • Network Security Groups and Firewalls
   • Azure Key Vault
   • Microsoft Defender for Cloud

Core Services Architecture

Compute

Virtual Machines

• VM sizes: General (D-series), Compute (F-series), Memory (E-series), GPU (N-series)
• Availability Sets (99.95% SLA)
• Availability Zones (99.99% SLA)
• VM Scale Sets for auto-scaling
• Best practices: Use managed disks, enable accelerated networking, use proximity placement groups

App Service

• Web Apps, API Apps, Mobile Apps
• Deployment slots for staging
• Auto-scaling based on metrics or schedule
• Supports .NET, Java, Node.js, Python, PHP, Ruby
• Best practices: Use deployment slots, enable auto-scaling, use App Service Plan efficiently

Azure Functions

• Consumption Plan (serverless)
• Premium Plan (VNet integration, no cold start)
• Dedicated Plan (App Service Plan)
• Durable Functions for orchestration
• Best practices: Keep functions small, use Premium for production, implement retry policies

Azure Kubernetes Service (AKS)

• Managed Kubernetes control plane
• Azure CNI or kubenet networking
• Azure AD integration
• Virtual nodes (Azure Container Instances)
• Best practices: Use system node pools, enable autoscaling, implement network policies

Container Instances

• Serverless containers
• Fast startup without infrastructure management
• Best for batch jobs and burstable workloads

Azure Batch

• Large-scale parallel and HPC workloads
• Auto-scaling compute nodes
• Task scheduling and dependencies

Storage

Blob Storage

• Storage tiers: Hot, Cool, Archive
• Access tiers: Premium, Standard
• Lifecycle management policies
• Immutable storage for compliance
• Best practices: Use lifecycle policies, enable soft delete, implement versioning

Azure Files

• SMB and NFS file shares
• Integration with Azure File Sync
• Premium tier for high performance
• Best practices: Use Premium for databases, implement snapshots

Disk Storage

• Managed Disks: Premium SSD, Standard SSD, Standard HDD, Ultra Disk
• Disk encryption with Azure Disk Encryption
• Snapshots and incremental backups
• Best practices: Use Premium SSD for production, enable encryption

Data Lake Storage Gen2

• Hierarchical namespace for big data
• Built on Blob Storage
• Integration with Azure Synapse and Databricks
• Best practices: Enable hierarchical namespace, use lifecycle policies

Azure NetApp Files

• Enterprise-grade NFS and SMB shares
• High performance and low latency
• Snapshots and data protection

Database

Azure SQL Database

• Serverless and provisioned compute
• Hyperscale for up to 100TB
• Elastic pools for multiple databases
• Auto-tuning and intelligent insights
• Best practices: Use serverless for dev/test, enable geo-replication

Azure SQL Managed Instance

• Near 100% compatibility with SQL Server
• VNet integration for isolation
• Native virtual network implementation
• Best practices: Use for lift-and-shift migrations

Cosmos DB

• Multi-model NoSQL database
• Global distribution with multi-master
• Consistency levels: Strong, Bounded staleness, Session, Consistent prefix, Eventual
• APIs: SQL, MongoDB, Cassandra, Gremlin, Table
• Best practices: Choose appropriate consistency, partition key design critical

Azure Database for PostgreSQL/MySQL/MariaDB

• Flexible Server (newer) vs Single Server (legacy)
• High availability with zone redundancy
• Read replicas for scaling
• Best practices: Use Flexible Server, enable HA, implement connection pooling

Azure Cache for Redis

• In-memory caching
• Clustering for scalability
• Geo-replication for disaster recovery
• Best practices: Use Premium tier for production, enable persistence

Networking

Virtual Network (VNet)

• CIDR planning (avoid overlaps)
• Subnets with Network Security Groups
• Service endpoints and Private Link
• VNet peering for connectivity
• Best practices: Plan IP address space, use NSGs, implement Private Link

Azure Load Balancer

• Layer 4 load balancing
• Standard SKU (zone-redundant, SLA)
• Health probes and distribution algorithms
• Best practices: Use Standard SKU, configure health probes

Application Gateway

• Layer 7 load balancing
• WAF (Web Application Firewall)
• URL-based routing and SSL termination
• Best practices: Enable WAF, use autoscaling

Azure Front Door

• Global load balancing and CDN
• WAF at edge
• Anycast for low latency
• Best practices: Use for global applications, enable caching

VPN Gateway and ExpressRoute

• Site-to-Site VPN for encrypted connectivity
• ExpressRoute for private, dedicated connection
• Virtual WAN for global transit network
• Best practices: Use ExpressRoute for production, implement redundancy

Azure Firewall

• Managed firewall service
• Application and network rules
• Threat intelligence
• Best practices: Use in hub-spoke topology, enable DNS proxy

Azure Private Link

• Private connectivity to Azure services
• No public internet exposure
• Available for PaaS services
• Best practices: Use for all PaaS services in production

Security and Identity

Azure Active Directory (Microsoft Entra ID)

• Identity and access management
• Conditional Access policies
• Multi-factor authentication
• B2B and B2C scenarios
• Best practices: Enable MFA, use Conditional Access, implement PIM

Azure Key Vault

• Secrets, keys, and certificates management
• Hardware Security Module (HSM) backed
• Soft delete and purge protection
• Best practices: Enable soft delete, use RBAC, implement Private Link

Microsoft Defender for Cloud

• Security posture management
• Threat protection for hybrid workloads
• Regulatory compliance dashboard
• Just-in-time VM access
• Best practices: Enable enhanced security, implement recommendations

Azure Policy

• Governance and compliance at scale
• Built-in and custom policies
• Deny, audit, append effects
• Best practices: Assign at management group level, test before enforce

Azure Sentinel

• Cloud-native SIEM and SOAR
• AI-powered threat detection
• Integration with Microsoft 365, third-party tools
• Best practices: Enable data connectors, create custom analytics rules

Architecture Patterns

High Availability

Zone-Redundant Pattern

Azure Front Door (global)
    |
    v
Application Gateway (zone-redundant)
    |
    v
VM Scale Set (across availability zones)
    |
    v
Azure SQL Database (zone-redundant)

Multi-Region Pattern

Azure Traffic Manager (DNS-based routing)
    |
    ├── Region 1: App Service + SQL Database (primary)
    └── Region 2: App Service + SQL Database (geo-replica)

Hub-Spoke Topology

Hub VNet
├── Azure Firewall
├── VPN Gateway
└── Shared Services
    |
    ├── Spoke VNet 1 (Production)
    ├── Spoke VNet 2 (Development)
    └── Spoke VNet 3 (DMZ)

Serverless Architecture

Event-Driven Pattern

Event Grid -> Azure Functions -> Cosmos DB
                    |
                    v
              Service Bus -> Functions (processing)

API-First Pattern

API Management
    |
    ├── Function App 1 (auth)
    ├── Function App 2 (business logic)
    └── Function App 3 (data access)

Microservices on Azure

AKS-Based

Azure Front Door
    |
    v
Application Gateway + WAF
    |
    v
AKS (multiple microservices)
    |
    ├── Cosmos DB (microservice A)
    ├── SQL Database (microservice B)
    └── Service Bus (async communication)

Container Apps Pattern

Azure Container Apps
├── Dapr for state management
├── KEDA for event-driven scaling
└── Azure Monitor for observability

Data Platform

Data Sources
    |
    v
Event Hubs / IoT Hub
    |
    v
Stream Analytics (real-time processing)
    |
    v
Data Lake Storage Gen2
    |
    v
Azure Synapse Analytics
    |
    v
Power BI (visualization)

Landing Zone Design

Enterprise-Scale Landing Zone

Management Group Hierarchy

Tenant Root Group
├── Platform
│   ├── Management (monitoring, automation)
│   ├── Connectivity (hub networks, VPN)
│   └── Identity (domain controllers)
└── Landing Zones
    ├── Corp (internal workloads)
    └── Online (internet-facing workloads)

Network Topology

Hub VNet (Connectivity subscription)
├── Azure Firewall
├── VPN Gateway
├── ExpressRoute Gateway
└── Bastion

Spoke VNets (Workload subscriptions)
├── Production VNet
├── Staging VNet
└── Development VNet

Governance

• Azure Policy for compliance
• Management groups for hierarchy
• RBAC assignments at appropriate scope
• Resource tags for cost allocation
• Azure Blueprints for repeatable deployments

Migration Strategies

Azure Migrate

1. Assess

   • Discovery with Azure Migrate appliance
   • Dependency analysis
   • Performance-based sizing
   • Cost estimation

2. Migrate

   • Azure Migrate: Server Migration (agentless)
   • Database Migration Service
   • App Service Migration Assistant
   • Data Box for large data transfers

3. Optimize

   • Right-sizing recommendations
   • Reserved instances
   • Azure Hybrid Benefit

Migration Patterns

Rehost: Azure Migrate for VMs Replatform: App Service, Azure SQL Database Refactor: Container Apps, AKS, Functions Rebuild: Azure-native services (Cosmos DB, Cognitive Services)

Cost Optimization

Compute Savings

• Azure Reserved Instances (1-year or 3-year, up to 72% savings)
• Azure Savings Plans for Compute (up to 65% savings)
• Spot VMs for fault-tolerant workloads (up to 90% savings)
• Azure Hybrid Benefit (use existing Windows Server/SQL licenses)
• Auto-shutdown for dev/test VMs

Storage Savings

• Blob Storage lifecycle policies (Hot -> Cool -> Archive)
• Azure Files: Standard tier for general use
• Managed Disks: Standard SSD instead of Premium if possible
• Delete unused snapshots and disks

Database Savings

• Serverless tier for Azure SQL Database
• Reserved capacity for Cosmos DB
• DTU model vs vCore (choose based on workload)
• Pause Azure Synapse when not in use

Monitoring

• Azure Cost Management + Billing
• Cost alerts and budgets
• Azure Advisor recommendations
• Resource tagging for cost allocation

Disaster Recovery

Azure Site Recovery

VM Replication

• Azure to Azure replication
• On-premises to Azure (VMware, Hyper-V, physical)
• RPO: 30 seconds to a few minutes
• Automated failover and failback

Recovery Plans

• Multi-tier application recovery
• Customizable scripts and manual actions
• Integration with Azure Automation

Backup Strategies

Azure Backup

• VM backups (application-consistent)
• SQL Server and SAP HANA in Azure VMs
• Azure Files backup
• Cross-region restore

Database Backup

• SQL Database: Automated backups (7-35 days)
• Cosmos DB: Continuous backup (30 days)
• Long-term retention policies

High Availability

RTO/RPO Targets

• Active-Active: Multi-region with Traffic Manager (near-zero)
• Active-Passive: Geo-replication with failover (minutes)
• Backup and Restore: Azure Backup (hours)

Monitoring and Observability

Azure Monitor

Components

• Metrics: Time-series data (1-minute resolution)
• Logs: Log Analytics workspace for queries (KQL)
• Alerts: Metric, log, and activity log alerts
• Dashboards: Custom visualizations

Application Insights

• APM for web applications
• Distributed tracing
• Live Metrics Stream
• Smart detection and anomaly detection
• Best practices: Instrument all applications, set up availability tests

Log Analytics

KQL Queries

// Performance analysis
Perf
| where CounterName == "% Processor Time"
| summarize avg(CounterValue) by bin(TimeGenerated, 5m), Computer
| render timechart

// Failed requests
requests
| where success == false
| summarize count() by resultCode, bin(timestamp, 1h)

Workbooks

• Interactive reports
• Parameterized queries
• Combining metrics and logs

Identity and Access

Azure AD Best Practices

• Enable MFA for all users
• Use Conditional Access policies
• Implement Privileged Identity Management (PIM)
• Regular access reviews
• Break-glass accounts

RBAC Design

Built-in Roles

• Owner: Full access including RBAC
• Contributor: Full access except RBAC
• Reader: Read-only access
• Custom roles for specific needs

Scope Hierarchy

Management Group (highest)
    |
Subscription
    |
Resource Group
    |
Resource (lowest)

Best practices: Assign at highest appropriate scope, use groups not individual users, apply least privilege