Choosing the Right Cloud Migration Framework: Strategy First, Tools Second
Migrating to the cloud is no longer a technical decision. It’s a strategic one. Organizations moving from legacy systems to modern cloud environments must evaluate not only how to migrate but which framework aligns with their business priorities, workloads, and long-term architecture. Two of the most widely adopted models are:
- AWS’s 6 Rs Migration Framework: A Tactical, application-focused model
- Microsoft’s Cloud Adoption Framework (CAF): A comprehensive, organizational lifecycle model
This guide compares these two cloud migration strategies side-by-side, helping you decide which approach best suits your current stage and future cloud goals.
What Is the AWS 6 Rs Framework?
The AWS 6 Rs framework categorizes six primary migration paths organizations can follow when moving applications to the cloud. These Rs—Rehost, Replatform, Repurchase, Refactor, Retire, and Retain—are designed to match workloads with suitable migration tactics based on technical complexity, budget, and business needs.
1. Rehost (“Lift and Shift”)
Rehosting is the fastest route to the cloud, involving minimal changes to applications. You move your workloads as-is from on-prem to virtualized cloud infrastructure. This approach is common when facing tight timelines or lacking internal resources for major refactoring.
Example: Moving a legacy ERP system to EC2 without code changes.
2. Replatform
Also called “lift, tinker, and shift,” this method includes slight optimizations without altering core app architecture. You might update the OS, switch databases, or modify runtime components to improve performance or reduce licensing costs.
Example: Moving an application to AWS RDS instead of managing SQL Server on a VM.
3. Repurchase
Here, organizations replace the existing system with a cloud-native SaaS offering. This is often driven by cost-efficiency or the desire to retire maintenance-heavy systems.
Example: Replacing an on-prem CRM with Salesforce or HubSpot.
4. Refactor / Re-architect
Refactoring involves deeply modifying or rebuilding applications to take full advantage of cloud-native features. It’s the most resource-intensive but yields the highest agility, scalability, and modernization benefits.
Example: Rebuilding a monolithic app using microservices on AWS Lambda.
5. Retire
After an application inventory assessment, some systems may be decommissioned. Retiring eliminates unnecessary workloads that consume resources and budget.
6. Retain
Some systems, due to regulatory, technical, or strategic reasons, stay on-prem temporarily or permanently. These may be candidates for hybrid infrastructure planning.
Summary Table: AWS 6 Rs at a Glance
| Migration Type | Complexity | Speed | Benefit | Best For |
| Rehost | Low | Fast | Quick migration | Legacy apps |
| Replatform | Low-Med | Medium | Better performance | Minor upgrades |
| Repurchase | Medium | Medium | Reduced maintenance | SaaS-ready needs |
| Refactor | High | Slow | Cloud-native benefits | Scalability, innovation |
| Retire | Low | Fast | Cost savings | Obsolete workloads |
| Retain | Low | None | Strategic hold | Regulatory systems |
For more in-depth analysis of how to apply this framework, explore our guide on cloud migration strategy using AWS 6 Rs.
What Is the Microsoft Cloud Adoption Framework (CAF)?
While AWS focuses on application migration paths, Microsoft’s Cloud Adoption Framework (CAF) offers a structured approach to entire cloud transformation journeys. It guides organizations through strategy, planning, technical readiness, governance, and operations in six interconnected stages.
1. Strategy
This initial phase identifies motivations for cloud adoption, expected business outcomes, and strategic alignment with stakeholders.
Example: Improving uptime, enabling remote access, or meeting compliance mandates.
2. Plan
The planning stage focuses on assessing the current digital estate, building a cloud roadmap, and aligning people, processes, and technology. This includes financial modeling and workload prioritization.
3. Ready
This phase prepares the landing zone—your foundational cloud environment—based on security, network, and identity standards. Microsoft offers tools like Azure Blueprints and Bicep for consistent, policy-based infrastructure setup.
4. Adopt
Workloads are migrated or innovated in this stage. Like AWS’s 6 Rs, this phase covers technical execution—rehosting, refactoring, or rebuilding systems in Azure. However, it is part of a broader transformation cycle.
5. Govern
CAF embeds governance as a core pillar, helping organizations enforce security policies, monitor compliance, and reduce risk using tools like Azure Policy and Defender for Cloud.
6. Manage
Ongoing operations, support, monitoring, and optimization are structured under the Manage phase, ensuring stability, performance, and cost control post-migration.
Microsoft CAF: Lifecycle-Oriented Cloud Adoption Model
| Phase | Focus | Tools & Techniques |
| Strategy | Define motivation and outcomes | Cloud journey tracker |
| Plan | Assessment and roadmap | Azure Migrate |
| Ready | Prepare landing zone | Azure Blueprints, ARM templates |
| Adopt | Migrate and innovate | Azure DevOps, IaaS, PaaS |
| Govern | Security, risk, compliance | Azure Policy, Defender |
| Manage | Monitor, optimize, support | Azure Monitor, Log Analytics |
If you want a step-by-step walkthrough of planning and executing cloud migration holistically, see our post on end-to-end cloud migration strategy.
Core Differences Between AWS 6 Rs and Microsoft CAF
While both frameworks support cloud transformation, they approach the journey from distinct angles:
| Dimension | AWS 6 Rs | Microsoft CAF |
| Model Type | Tactical (workload-focused) | Strategic (organization-focused) |
| Key Users | Cloud engineers, DevOps | CIOs, IT managers, architects |
| Focus Area | Application migration | Full adoption lifecycle |
| Governance | Not embedded | Core phase (Govern) |
| Migration Planning | Pattern-based | Strategy-to-operations model |
| Ecosystem Integration | AWS cloud-native tools | Azure + Microsoft 365 stack |
Use Case Comparison: When to Use AWS 6 Rs vs Microsoft CAF
Choosing between AWS’s 6 Rs and Microsoft’s Cloud Adoption Framework depends on your goals, resources, and how you define “cloud success.” Below is a breakdown of real-world use cases to help clarify which model suits your needs.
When AWS 6 Rs Works Best
1. App-Level Migration Focus
If your main goal is to move specific workloads to the cloud quickly without large-scale change management, AWS 6 Rs provides actionable decision trees.
Example: A logistics company needs to rehost legacy Windows applications during a hardware refresh. They apply Rehost and Replatform to transition their environment in 30 days with minimal code changes.
2. Minimal Organizational Overhaul
You don’t need extensive governance, strategic realignment, or centralized tooling. You want tactical migrations guided by technical teams.
3. DevOps-Led Projects
If your IT staff prefers working within CI/CD pipelines, IaaS, or container services like ECS and EKS, the 6 Rs integrates well with agile DevOps cultures.
📌 Avoid misapplication of the 6 Rs by reviewing our breakdown of common 6 Rs migration mistakes.
When Microsoft CAF Is the Better Fit
1. Enterprise-Wide Transformation
You are not just migrating apps—you’re redefining how IT operates across departments. CAF supports multiple stakeholders, including compliance, finance, and operations.
Example: A healthcare organization needs HIPAA-compliant cloud infrastructure. Microsoft CAF provides a complete governance model, adoption blueprint, and compliance mapping through Azure Policy and Defender.
2. Governance and Cost Control Are Critical
CAF embeds policy creation, access control, and budgeting into its lifecycle—ideal for regulated industries or large organizations with distributed ownership.
3. Cloud Adoption Includes Modernization
Beyond simple lift-and-shift, CAF guides teams through innovation, workload automation, and integration with Microsoft 365, Power Platform, or Dynamics 365.
📌 Use our cloud strategy selection guide to evaluate the right path across business functions.
Mapping AWS 6 Rs to Microsoft CAF Stages
While the frameworks differ, they aren’t mutually exclusive. In fact, AWS’s 6 Rs can be applied within the CAF’s “Adopt” stage. Below is a mapping that helps unify both models:
| AWS Migration Type | CAF Stage | How They Align |
| Rehost | Adopt – Migrate | Lift workloads using Azure Migrate or Site Recovery |
| Replatform | Adopt – Migrate | Use Azure App Services or PaaS models |
| Repurchase | Plan – Rationalize | Replace with SaaS (e.g., Microsoft 365) |
| Refactor | Adopt – Innovate | Use containers, serverless, or microservices in Azure |
| Retire | Plan – Portfolio Assessment | Remove redundant apps |
| Retain | Strategy / Govern | Document for future review or compliance reasons |
Combining both frameworks allows organizations to stay tactical in execution while remaining strategic in planning and governance.
Decision Matrix: Which Framework Should You Choose?
| Business Situation | Recommended Model | Why |
| Need to move 5–10 workloads quickly with minimal effort | AWS 6 Rs | Application-centric, fast time-to-cloud |
| Merging IT environments across departments | Microsoft CAF | Strategy alignment + governance model |
| Migrating custom-built internal software | AWS 6 Rs | Refactor, Replatform, or Rehost as needed |
| Building a compliance-first cloud roadmap | Microsoft CAF | Built-in security, compliance, and cost control |
| Replacing licensed apps with SaaS | Either | Repurchase path + Plan stage both support this |
| Have a hybrid environment (on-prem + cloud) | Microsoft CAF | Supports hybrid identity, networking, and monitoring |
Key Cloud Migration Concepts
| Term | Definition | Context |
| Landing Zone | Preconfigured cloud setup with security, networking, identity controls | Used in CAF Ready stage |
| Rehost | Move apps to cloud without code changes | Common AWS 6 Rs path |
| Azure Policy | Microsoft tool for governance and compliance enforcement | CAF Govern phase |
| Lift and Shift | Move workloads as-is | Simple rehosting approach |
| Refactor | Rewriting apps for cloud-native services | Used in AWS 6 Rs and CAF Adopt stage |
| Cloud-Native | Architecture designed to fully utilize cloud models | Goal of innovation stages |
| Portfolio Assessment | Review of all current applications and infrastructure | Part of CAF Plan phase |
| Governance | Enforced standards, policies, and security rules | Key in CAF but missing in AWS 6 Rs |
| Rationalize | Decide what to migrate, replace, or retire | Planning tool in both frameworks |
| Workload | A specific application, process, or service running in IT environment | Migration unit across both models |
Final Recommendation: Strategy First, Execution Second
If your organization is moving a few apps and needs a straightforward, team-led approach, start with AWS 6 Rs. Match each workload to a migration tactic and move based on resource constraints, budget, and timeline.
If you’re building a sustainable, enterprise-grade cloud operation, especially in Azure, adopt Microsoft CAF. It forces alignment between business, operations, and security from day one, minimizing surprises and maximizing long-term agility.
Most mature cloud teams use a hybrid strategy:
- CAF for stakeholder alignment, governance, and adoption roadmap
- 6 Rs for execution-level migration decisions on a per-app basis
Need a Migration Strategy Built for You?
At CitySource Solutions, we help organizations make the right cloud decisions—no guesswork, no rework. Whether you’re:
- Running apps on AWS and need a clean migration plan
- Migrating into Azure with strict governance and compliance demands
- Navigating hybrid cloud complexity or licensing confusion
…we bring strategy and engineering together to build the right cloud environment.
📞 Schedule a consultation or visit our cloud services page to get started.
Frequently Asked Questions (FAQ)
What’s the main difference between AWS 6 Rs and Microsoft CAF?
AWS 6 Rs focuses on application-level migration tactics—rehost, refactor, retire, etc.—to determine how each workload should move to the cloud. Microsoft CAF addresses the full enterprise adoption lifecycle, from planning and governance to ongoing operations. One is tactical, the other strategic.
Can I use both frameworks together?
Yes. Many organizations use AWS 6 Rs during the “Adopt” phase of Microsoft CAF. For example, once your CAF plan identifies 50 apps to migrate, the 6 Rs framework helps define how each app moves, whether to rehost, refactor, or retire.
Which framework is better for regulatory compliance?
Microsoft CAF offers built-in tools and structured phases for security, governance, and compliance—especially for industries like healthcare, finance, and legal. CAF’s “Govern” phase uses tools like Azure Policy and Microsoft Defender for Cloud to enforce rules across all services.
Which framework is faster to implement?
AWS 6 Rs can be applied quickly to individual workloads, especially when speed-to-cloud is the goal. For example, a rehost strategy can be executed within days or weeks. In contrast, CAF requires broader organizational alignment and planning, which makes it ideal for long-term transformation.
Is Microsoft CAF limited to Azure?
Yes, Microsoft CAF is designed specifically for Azure cloud environments. While its strategic principles can be adapted, the tools and templates (Azure Migrate, Landing Zones, Blueprints) are exclusive to Microsoft’s cloud ecosystem.
Do I need governance if I’m only migrating 2–3 apps?
Even small migrations benefit from light governance. While you may not need CAF’s full lifecycle, defining access controls, logging standards, and budget limits will avoid security gaps or cloud cost surprises. Use a CAF-lite approach for SMBs.
