AZ-305 migration questions usually ask for the right modernization depth, not just the name of a migration tool. The decision starts with business drivers, current workload constraints, dependency risk, available skills, outage tolerance, and how much change the application can safely absorb.
Use the strategy words as design signals. Rehost means move quickly with minimal application change. Replatform or refactor means accept limited changes to gain managed platform benefits. Rearchitect means the current architecture must change to meet scale, resiliency, maintainability, or cloud operating goals. Rebuild means the existing codebase is no longer the right modernization base.
Start With Discovery, Not Cutover
When dependencies, sizing, readiness, or migration waves are unknown, assess before planning execution. Azure Migrate supports discovery, assessment, dependency analysis, and migration planning across workload types. In an exam scenario, that means Azure Migrate is often the planning answer before it is the move-the-workload answer.
Do not collapse every migration need into one application strategy. Database and unstructured-data migrations can affect sequencing and tools, but application target choice still needs its own decision model: compatibility, required control, operational effort, modernization value, and dependency risk.
Strategy Comparison for Exam Scenarios
| Scenario signal | Better exam move |
|---|---|
| Stable workload, tight timeline, minimal change allowed | Rehost, while recognizing technical debt may remain. |
| The app can tolerate limited code or platform changes | Replatform or refactor to gain managed platform value without full redesign. |
| Current architecture blocks scale, resilience, maintainability, or operations | Rearchitect because the design itself must change. |
| Existing code or architecture is not a viable base | Rebuild as a new cloud-native solution. |
| Dependencies, sizing, or readiness are unknown | Use discovery, assessment, and dependency analysis before waves or cutover. |
| Application and database moves appear together | Separate the application target decision from data-platform compatibility and cutover tooling. |
One major trap: rehost is not automatically the safest answer. It changes less, but it can also preserve the same operational problems, brittle dependencies, and technical debt that made modernization necessary.
Worked Scenario
A company runs an internal order-processing application on on-premises virtual machines. Leadership wants a fast Azure move before a datacenter exit date, and the application is stable enough to run as-is for the next year. The dependency map shows a few databases and identity integrations, but no requirement for an immediate architecture redesign.
For AZ-305, the first defensible strategy is rehost, supported by discovery, assessment, dependency mapping, migration wave planning, and validation. Replatforming or refactoring might be a later phase, but the scenario's near-term driver is rapid relocation with minimal application change.
Change one fact and the answer changes. If the same application cannot meet required availability or scale because of its current design, rehost becomes a weak answer and rearchitect becomes more defensible. If the codebase is obsolete and the business wants a cloud-native replacement rather than migration of the existing app, rebuild becomes the better strategy.
Compact Decision Rules
Use these rules when answer choices all look plausible:
| Ask this first | Why it matters |
|---|---|
| Is the business driver speed or modernization? | Speed favors rehost; modernization pressure moves the answer toward refactor, rearchitect, or rebuild. |
| How much application change is allowed before cutover? | Minimal change points to rehost; limited change points to replatform or refactor; material design change points to rearchitect. |
| Are dependencies and sizing known? | Unknown dependencies or right-sizing needs require assessment and dependency analysis before execution. |
| Does the target need IaaS control or PaaS operations? | IaaS can preserve control and compatibility; PaaS can reduce operations when the workload fits. |
| Are database or storage moves part of the scenario? | Treat them as adjacent migration decisions that can drive sequencing and tooling. |
Quick Recap
If the interactive checks do not load, remember the exam sequence: define the business driver, discover and assess the estate, map dependencies, choose the migration strategy from modernization depth and change tolerance, then select tooling and migration waves. Rehost is for fast low-change relocation, replatform or refactor is for limited modernization, rearchitect is for material design change, and rebuild is for replacing a nonviable application base.
Ready to test this under realistic constraints? Take the targeted AZ-305 assessment and look for migration scenarios where the right answer changes because of modernization depth, dependency discovery, or tool timing.