The 6 R's: Your Playbook for Cloud Migration
The 6 R's are a strategic menu for migrating apps to the cloud. When planning a move, you use it to decide whether to simply 'Rehost' an app, 'Refactor' it for performance, or even 'Retire' it.
Why it exists
Moving an entire portfolio of applications to the cloud is complex. Without a plan, teams often default to the easiest path, which may not be the best long-term. The 6 R's provide a structured framework to assess each application and choose the most appropriate migration strategy, preventing chaos and optimizing outcomes.
The mental model
Think of the 6 R's as a decision guide for moving houses. Some items you just pack and move as-is (Rehost). Some you fix up a bit to better fit the new house (Replatform). Some you rebuild entirely for the new space (Rebuild). Some you throw away because they're obsolete (Retire). And some you leave behind in storage for now (Retain).
How it works
This framework gives you six distinct strategies for any given application. First, Rehost (lift and shift) moves an application to cloud infrastructure with no code changes. Second, Replatform (lift, tinker, and shift) involves minimal changes to take advantage of cloud platforms, like moving to a managed database. Third, Refactor involves significant code changes to modernize the application for a cloud-native environment. Fourth, Rebuild means starting over and writing a new application from scratch. Fifth, Retire is decommissioning an application that is no longer needed. Finally, Retain means choosing to do nothing and leaving the application where it is for now.
When to use it
Use this framework during the initial planning phase of any cloud adoption or application modernization initiative. It forces you to categorize every application, creating a clear roadmap that aligns business and technical teams on the required effort, cost, and expected benefits for each part of your software portfolio.
When not to use it
The 6 R's framework is a high-level strategic tool, not a detailed technical guide. It won't tell you how to refactor a service, only that refactoring is the chosen strategy. It's also less relevant for a single, new application being built from scratch specifically for the cloud.
One canonical example
A company moving to the cloud assesses its applications. Its internal wiki is Rehosted directly onto a cloud server. Its e-commerce backend is Replatformed to use a managed database service. Its monolithic payment service is Refactored into microservices for scalability. An old, unused reporting tool is Retired. The complex legacy mainframe system is Retained in the on-premise data center for now due to the high risk of moving it.
Interview question
What is the primary purpose of applying the 6 R's framework during cloud migration planning?
- a.To provide a structured approach for assessing existing applications and selecting an appropriate cloud migration strategy.Correct
- b.To automate the entire cloud migration process, reducing manual effort and human error.
- c.To standardize the migration process by ensuring all applications are moved using the "lift and shift" method.
- d.To generate a comprehensive technical blueprint for cloud-native application development.
Why? this is the answer
The 6 R's framework is designed to help organizations evaluate each existing application and choose the most suitable migration strategy from a set of six options. It is a strategic decision-making tool, not a detailed technical guide or an automation solution, nor does it mandate a single migration method like "lift and shift" for all applications.
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