The 7 Rs (also called migration strategies or “disposition options”) are the standardised framework for deciding how each workload should be treated during a migration programme. The AZ-305 exam tests whether you can match a scenario to the correct R.
flowchart LR
WL["Workload"]
WL --> R1["🗑️ Retire\nDecommission — no business value"]
WL --> R2["🔒 Retain\nStay on-prem — not ready for cloud"]
WL --> R3["🚀 Rehost\nLift-and-shift to IaaS VM"]
WL --> R4["🔧 Replatform\nMinimal change — managed service"]
WL --> R5["🏗️ Rearchitect\nModify code for cloud-native patterns"]
WL --> R6["🔨 Rebuild\nRewrite from scratch — cloud-native"]
WL --> R7["🛒 Replace\nSwitch to SaaS product"]
Detailed 7 Rs Reference
Strategy
Also Called
Description
Azure Example
Effort
Retire
Decommission
Shut the workload down — no business value
—
None
Retain
Revisit
Keep on-premises — compliance, latency, or not yet ready
—
None
Rehost
Lift-and-shift
Move VM as-is to Azure IaaS — no code or config changes
On-prem VM → Azure VM
Low
Replatform
Lift-and-reshape
Minor optimisation for a managed service — minimal code change
SQL Server on VM → Azure SQL MI
Low–Medium
Rearchitect
Refactor
Modify application code to leverage cloud-native capabilities
Monolith → microservices on AKS
High
Rebuild
Rewrite
Build the application from scratch using cloud-native services
Legacy app → Azure Functions + Cosmos DB
Very High
Replace
Drop-and-shop
Retire and adopt an equivalent SaaS product
Custom CRM → Dynamics 365 / Salesforce
Medium
⚠️ Exam Caveat — Rehost vs Replatform: These two are the most commonly confused.
Rehost: VM moves to Azure VM — OS, app, config unchanged. Tool: Azure Migrate.
Replatform: App moves to a managed service (App Service, SQL MI) — app code is unchanged but the runtime or database engine changes slightly. Tool: DMS, App Service Migration Assistant.
If the scenario says “no code changes, move the VM as-is”, the answer is Rehost. If it says “move SQL Server to a managed service with minimal changes”, the answer is Replatform.
Cloud Adoption Framework (CAF)
The Microsoft Cloud Adoption Framework (CAF) is the structured methodology for planning and executing cloud migrations. The migration-specific phases are:
Phase
Activities
1. Strategy
Define business justification, migration motivations, business outcomes
2. Plan
Digital estate inventory (Azure Migrate), prioritise workloads, build migration backlog
An Azure Landing Zone is a pre-configured, governed Azure environment that provides the foundation for migrated workloads — networking, security, identity, management, and compliance baselines are all in place before the first workload arrives.
⚠️ Exam Caveat — Landing Zone Before Migration: The exam expects you to include Landing Zone readiness as a prerequisite step before migrating workloads. If a scenario says “the team wants to start migrating immediately without any Azure preparation”, the correct recommendation is to deploy a Landing Zone first (even a simplified one).