6Rs of Cloud Migration

What are the 6Rs of cloud migration?

The "6Rs of Cloud Migration" is a framework conceptualized by Amazon Web Services to outline the main approaches organizations can adopt when shifting to cloud computing. Although variations like Gartner's "5Rs" and other models proposing up to 9Rs exist, we focus on the 6Rs for its comprehensive yet pragmatic approach.

This strategy suite—Rehost, Replatform, Rearchitect, Repurchase, Retire, and Retain—covers the full spectrum of migration options, providing a balance between complexity, cost, and cloud optimization. The decision to adopt the 6Rs model is rooted in its widespread adoption and versatility, catering to a diverse range of migration needs and business objectives.

As we explore each R, we will highlight the scenarios in which each is most effective, its advantages, potential drawbacks, and a step-by-step approach to implementation.

By the end of this guide, you will have a comprehensive understanding of how to assess, plan, and execute a cloud migration strategy that is tailored to your organization's requirements. 

📚 Related: Cloud Migration Software

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1. Rehost (Lift and Shift)

Rehosting is the most straightforward strategy in the 6Rs framework, involving the migration of applications and data to the cloud with minimal changes.

Often the first choice for businesses looking to quickly capitalize on the benefits of cloud computing, Rehost enables organizations to move their existing on-premises applications to the cloud without the need to redesign the applications' architecture.

When to use rehosting: Rehosting is ideal for organizations that need to migrate quickly due to time constraints or cost pressures. It is also a suitable strategy for companies looking to scale their operations rapidly without immediate concern for cloud-native features.

Advantages of rehosting:

• Speed: Allows for the fastest migration to the cloud.
• Cost-effective: Minimizes upfront costs by avoiding major redesigns.
• Simplicity: Reduces complexity in the migration process.

Limitations of rehosting:

• Limited optimization: Does not take full advantage of cloud-native features that could improve performance and cost.
• Technical debt: May perpetuate legacy issues and inefficiencies into the cloud environment.

Step-by-step guide for rehosting:

1. Assessment: Identify workloads for migration and ensure they are compatible with the cloud provider's environment.
2. Planning: Develop a detailed migration plan, including resource allocation, scheduling, and risk mitigation strategies.
3. Preparation: Prepare the cloud environment for migration, including setting up virtual machines and storage.
4. Migration: Move applications and data to the cloud using automated tools or services provided by the cloud vendor.
5. Testing: Conduct post-migration testing to ensure functionality and performance match expectations.
6. Optimization: Begin the process of optimizing resources to take advantage of the cloud's scalability and elasticity.

2. Replatform (Lift, Tinker, and Shift)

Replatforming involves making some modifications to applications to take advantage of cloud capabilities without a complete overhaul or re-architecture. This strategy strikes a balance between the simplicity of rehosting and the complexity of rearchitecting.

When to use replatforming: Replatforming is suitable for businesses that are looking to benefit from cloud optimizations but want to avoid the costs and risks associated with a full rearchitecting. It's ideal when core application architecture is sound but could benefit from cloud efficiencies.

Advantages of replatforming:

• Enhanced efficiency: Optimizes applications to leverage cloud-native features like scalability and managed services.
• Cost savings: Can reduce operational costs by using cloud infrastructure more effectively than simple rehosting.
• Reduced risk: Less risky than full rearchitecting as core application architecture remains unchanged.

Limitations of replatforming:

• Limited transformation: While improvements are made, it may not fully harness all cloud-native functionalities.
• Potential adjustments: Some parts of the application may need to be adapted or rewritten to fit into the cloud environment.

Step-by-step guide for replatforming:

1. Evaluation: Assess which aspects of applications can benefit from cloud-native features.
2. Planning: Update the migration plan to incorporate platform-specific optimizations.
3. Adaptation: Make necessary adjustments to the application, such as leveraging managed databases or introducing auto-scaling.
4. Execution: Migrate the adapted applications to the cloud environment.
5. Validation: Test the performance and functionality of applications post-migration to ensure they meet new cloud-based expectations.
6. Enhancement: Continue to identify and implement incremental improvements to fully realize cloud benefits.

3. Rearchitect (Redesign for Cloud)

Rearchitecting, also known as refactoring, involves significant modifications to the existing application design to fully exploit the advantages of cloud-native technologies and services.

When to use rearchitecting: This strategy is apt for applications that need scalability, resilience, or need to add new features that are only feasible with a cloud-native architecture. It’s often chosen when an organization is looking to transform their business processes and capabilities through the cloud.

Advantages of rearchitecting:

• Full optimization: Maximizes the use of cloud-native features, potentially improving performance, scalability, and resilience.
• Long-term savings: Although initially costly, it can lead to greater efficiency and cost reductions in the long run.
• Innovation enablement: Facilitates the adoption of modern development practices and technologies, like microservices and serverless computing.

Limitations of rearchitecting:

• High initial cost: Requires a significant investment in terms of time, resources, and expertise.
• Complexity: Involves complex restructuring that can introduce risks during the transition.
• Business disruption: Potential for greater impact on business operations during the migration process.

Step-by-step guide for rearchitecting:

1. Comprehensive assessment: Conduct an in-depth analysis of the application to determine the feasibility and requirements for rearchitecting.
2. Strategic planning: Outline a clear roadmap for the transition, including timelines, expected benefits, and resource allocation.
3. Architecture redesign: Rebuild the application architecture to align with cloud-native practices, possibly breaking down monolithic applications into microservices.
4. Implementation: Develop and deploy the rearchitected application onto the cloud, often involving continuous integration/continuous deployment (CI/CD) pipelines.
5. Thorough testing: Rigorously test the new cloud-native application to ensure that it meets all functional and non-functional requirements.
6. Iterative optimization: Post-deployment, continually refine and optimize the application to fully leverage cloud capabilities and address emerging needs.

4. Repurchase (Move to a Different Product)

The repurchase strategy, sometimes referred to as "drop and shop," involves moving to a different product, typically by switching to a cloud-native solution or a Software as a Service (SaaS) application.

When to use repurchase: Repurchasing is ideal when existing applications are outdated or when a cloud-native solution offers significant advantages over rehosting or replatforming. It is also a strategic choice when reducing the operational burden of maintaining legacy systems.

Advantages of repurchase:

• Streamlining: Simplifies IT portfolios by reducing the number of applications that need to be managed.
• Access to innovation: Provides access to the latest functionalities and innovations that SaaS platforms frequently offer.
• Reduced maintenance: Shifts the responsibility of application maintenance and updates to the SaaS provider.

• Subscription costs: Can introduce ongoing operational expenses due to subscription models.
• Integration challenges: May require integration with existing systems and data migration efforts.
• Feature parity: There is a risk that the new product may not have all the features of the existing solution.

1. Market research: Identify potential SaaS products that meet the organization’s needs.
2. Cost-benefit analysis: Evaluate the costs, including any subscription fees, against the benefits of moving to the new product.
3. Vendor selection: Choose a vendor based on product capabilities, security, compliance, and support.
4. Data migration: Plan and execute the migration of data from the existing system to the new SaaS platform.
5. Integration: Ensure the new SaaS solution integrates well with the existing IT landscape.
6. User training: Provide training for end-users to effectively utilize the new system.

5. Retire (Get Rid of)

The retire phase involves identifying IT assets that are no longer useful and can be turned off during the migration. This step is crucial for decluttering the IT environment and focusing resources on maintaining and migrating only the necessary systems.

When to use retire: This strategy is applicable when certain applications or components are outdated, redundant, or no longer deliver value to the business. Retiring such assets can simplify the migration process and reduce costs.

Advantages of retire:

• Cost reduction: Eliminates the cost of maintaining and operating outdated systems.
• Simplification: Reduces the complexity of the IT environment and the scope of the migration.
• Focus on value: Allows organizations to focus on migrating and improving systems that provide real business value.
• Limitations of retire:
• Discovery challenges: It can be difficult to accurately identify and agree on which systems should be retired.
• Business alignment: Requires alignment with business units to ensure no critical processes are disrupted.

Identifying candidates for retirement:

1. Inventory assessment: Compile a comprehensive inventory of all IT assets and applications.
2. Usage analysis: Review usage statistics to identify rarely or never used assets.
3. Business consultation: Work with business stakeholders to understand the value and necessity of each asset.
4. Decommissioning plan: Develop a detailed plan for retiring each identified asset, including data archiving strategies if necessary.
5. Communication: Inform all relevant parties about the retirement plan and timeline to ensure a smooth transition.
6. Execution: Carry out the decommissioning process, ensuring all data is securely archived or deleted as appropriate.

6. Retain (Keep as Is)

Retaining involves choosing not to migrate certain applications or workloads to the cloud. This decision is typically based on specific business, technical, or regulatory factors that necessitate maintaining certain systems outside of the cloud.

When to use retain: Retention is a viable option when applications are tightly bound to legacy hardware that cannot be easily moved or when there are stringent regulatory and compliance requirements that are not yet addressed by cloud environments.

Advantages of retain:

• Compliance: Ensures that regulatory and compliance standards are strictly maintained.
• Stability: Preserves the stability of applications that are sensitive to changes.
• Cost management: Avoids unnecessary migration costs for systems that are not cloud-ready or beneficial to move.

Limitations of retain:

• Missed opportunities: May miss out on the benefits of cloud services for retained applications.
• Management complexity: Maintains the complexity of having a separate environment to manage alongside cloud infrastructure.

Managing retained assets:

1. Strategic review: Regularly review the reasons for retaining each asset to ensure they remain valid.
2. Integration considerations: Develop strategies to integrate retained systems with cloud-based services where possible.
3. Monitoring and support: Continue to monitor and support retained systems to ensure they meet business needs.
4. Future assessment: Keep retained systems under review for potential future migration as cloud services evolve and business needs change. 

📚 Related: Data-driven Cloud Transformation

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Choosing the right “R” strategy

The choice of the right cloud migration strategy depends on cloud migration assessment and a variety of factors, including business goals, technical requirements, cost implications, time constraints, and regulatory considerations.

Factors to consider

• Business objectives: Align the migration strategy with the company's broader business goals, such as agility, innovation, or cost savings.
• Application suitability: Consider the cloud readiness of applications and whether they require significant modification to benefit from the cloud.
• Compliance and security: Evaluate regulatory compliance needs and security requirements that may dictate the migration approach.
• Resource availability: Assess internal and external resources, including skills, budget, and time available for the migration.
• Long-term vision: Consider how each strategy fits into the long-term IT and business strategy.

Comparison of the 6Rs

• Rehost offers speed and cost-effectiveness for immediate migration needs.
• Replatform balances minimal changes with some cloud optimizations.
• Rearchitect provides full cloud-native capabilities at a higher cost and complexity.
• Repurchase enables a move to modern SaaS solutions with ongoing subscription costs.
• Retire eliminates unnecessary costs and complexity from legacy systems.
• Retain keeps certain systems in place due to technical or business constraints.

📚 Related: Are the Benefits of Application Migration Becoming Cloudy?

Implementing the 6Rs in your cloud migration plan

Integrating the 6Rs into your cloud migration roadmap (aka application modernization roadmap) requires careful planning and execution. Here are a few best practices for implementing your chosen strategies.

• Comprehensive planning: Develop a detailed plan that addresses the scope, timelines, and resources for the chosen strategy.
• Stakeholder engagement: Ensure all stakeholders are on board and informed throughout the migration process.
• Skills and training: Invest in training for your team to manage the new cloud environment effectively.
• Pilot projects: Run pilot migrations when possible to test the strategy and refine the approach.
• Vendor collaboration: Work closely with cloud service providers to leverage their tools and expertise.
• Continuous optimization: After migration, continuously assess and optimize the cloud environment to ensure it delivers the expected benefits.

By following these best practices, organizations can implement the 6Rs effectively, ensuring a smooth transition to the cloud and alignment with strategic business outcomes.

📚 Related: How to Kickstart your Cloud Migration Journey? and Cloud Migration Challenges

Conclusion

Concluding our journey through the "6Rs of Cloud Migration," remember that each strategy offers a unique path to the cloud. The right choice balances your business needs with the potential of cloud technology, ensuring a migration that's not just about moving to the cloud, but about moving forward.