Migration Strategy & Assessment
Cloud Adoption Framework, the 5 R's of migration, Azure Migrate, and landing zones — design a migration strategy that gets workloads to Azure safely and efficiently.
Migration strategy design
Migration is like moving house. You wouldn’t throw everything in a truck without a plan. The Cloud Adoption Framework (CAF) is your moving plan — it tells you what to assess, what order to move things, and how to set up your new “house” (landing zone) before the first box arrives.
The 5 R’s describe what to do with each workload: Rehost (lift and shift), Refactor (minor changes), Rearchitect (redesign), Rebuild (start over), or Replace (use SaaS).
Cloud Adoption Framework phases
| Phase | Purpose | Key Activities |
|---|---|---|
| Strategy | Define motivation and business outcomes | Why migrate? Cost reduction? Innovation? Compliance? |
| Plan | Create the migration plan | Inventory workloads, prioritise, create timeline |
| Ready | Prepare the Azure environment | Set up landing zones, networking, governance |
| Adopt (Migrate) | Execute the migration | Assess → migrate → optimise each workload |
| Adopt (Innovate) | Build new cloud-native solutions | Modernise apps, build new capabilities |
| Govern | Establish governance controls | Policies, cost management, compliance |
| Manage | Ongoing operations | Monitor, optimise, maintain |
The 5 R’s of migration
| Strategy | What Changes | Effort | Benefit | Best For |
|---|---|---|---|---|
| Rehost (lift and shift) | Nothing — move as-is to Azure VMs | Lowest | Quick migration, same app | Legacy apps, quick wins, IaaS migration |
| Replatform / Refactor | Minor changes for PaaS compatibility | Low-medium | Reduced management, some PaaS benefits | Apps that work on App Service/containers with small changes |
| Rearchitect | Significant redesign for cloud-native | High | Full cloud benefits, scalability | Apps that need cloud-native features to scale |
| Rebuild | Rewrite from scratch | Highest | Optimal cloud design | Apps where existing code is a liability |
| Replace | Switch to SaaS | Medium | Zero management | Commodity functions (email, CRM, ERP) |
Terminology note: Microsoft uses varying terminology across docs. Azure Migrate assessments use “Replatform” for minor PaaS changes and reserve “Refactor” for heavier code changes. CAF docs use the original “Refactor” for minor changes. The exam may use either — recognise both.
🏗️ Priya’s migration strategy for GlobalTech (15 data centres, 200+ apps):
| Wave | Apps | Strategy | Rationale |
|---|---|---|---|
| Wave 1 | 50 simple web servers | Rehost → Azure VMs | Quick wins, reduce DC footprint fast |
| Wave 2 | 30 .NET web apps | Refactor → App Service | Minor changes, big ops reduction |
| Wave 3 | 10 core business apps | Rearchitect → containers/microservices | Need cloud-native scaling |
| Wave 4 | Legacy ERP | Replace → Dynamics 365 | ERP replacement was already planned |
| Wave 5 | 5 critical custom apps | Rebuild → cloud-native | Old code can’t be migrated meaningfully |
Azure Migrate
| Tool | What It Does |
|---|---|
| Discovery and assessment | Discovers on-prem VMs, databases, web apps. Creates Azure readiness reports with sizing and cost estimates. |
| Server Migration | Replicates VMs (VMware, Hyper-V, physical) to Azure with minimal downtime |
| Database Migration Service | Migrates SQL Server, PostgreSQL, MySQL with near-zero downtime |
| Web app migration assistant | Assesses .NET/Java web apps for App Service compatibility |
| Data Box | Physical device for bulk data transfer (TB to PB scale) |
Exam tip: Azure Migrate is the starting point for ALL migrations
Even if the scenario ultimately uses a different migration tool (DMS for databases, ASR for VMs), the assessment should always start with Azure Migrate. It provides the readiness assessment, sizing recommendations, and cost estimates that inform the migration strategy. If the exam asks “first step in migration assessment” → Azure Migrate discovery and assessment.
Landing zones
A landing zone is a pre-configured Azure environment with networking, identity, governance, and security ready for workloads.
| Component | What It Provides |
|---|---|
| Identity | Entra ID tenant, hybrid identity (Entra Connect), Conditional Access |
| Networking | Hub-spoke VNet, DNS, VPN/ExpressRoute to on-prem |
| Governance | Management groups, Azure Policy, RBAC, cost management |
| Security | Microsoft Defender for Cloud, Sentinel, security baselines |
| Logging | Central Log Analytics workspace, diagnostic settings |
🏛️ David’s landing zone approach: “Never migrate a single VM before the landing zone is ready. I’ve seen organisations rehost 500 VMs into a flat network with no governance — it took 6 months to untangle. Build the foundation first.”
Knowledge check
🏗️ GlobalTech has a legacy .NET application using SQL Agent jobs, CLR stored procedures, and cross-database queries. The code is stable and well-tested. The goal is to migrate to Azure with minimal code changes. Which migration strategy should Priya recommend?
🏦 FinSecure Bank is migrating 500 servers to Azure over 12 months. Some applications span multiple servers with complex interdependencies. Elena needs to determine which servers should migrate together and in what order. The bank cannot afford application outages during migration. Which approach should she recommend?
🎬 Video coming soon
Next up: Executing the actual migration — Executing Migrations.