The 7 Rs of Cloud Migration (AWS)

The 7 Rs of Cloud Migration are a set of strategies that organizations can adopt based on their business goals, application architecture, and technical considerations when moving workloads to the cloud, specifically to AWS. Each strategy is chosen based on factors like cost, performance, effort, business value, and technical complexity.

1. Rehost (Lift and Shift)

definition : Rehosting is involves involve move application to AWS with minimal or no modification . It is often refer to as “ lift and shift ” because the application is literally lift from its exist environment and shift to the cloud without any change in the underlying architecture .

When to use :

• Ideal for organization look for a quick migration and where cost reduction or immediate cloud benefit are a priority .
• common for legacy application that may be difficult to modify or refactor .
• Short-term strategy for getting to the cloud quickly while planning for further optimizations later.

advantage :

• Fastest migration method since there is little re-engineering involved.
• enable immediate cloud adoption .
• Allows for cost reduction in infrastructure management, as the application is moved to a cloud-managed infrastructure.

Tools: AWS Application Migration Service, AWS Server Migration Service (SMS), AWS VM Import/Export.

2. Replatform (Lift, Tinker, and Shift)

Definition: Replatforming involves making minor optimizations or tweaks to the application to take advantage of some AWS cloud benefits without completely overhauling the core application architecture. This might include moving from self-managed databases to AWS-managed services like Amazon RDS.

When to use :

• Suitable for organizations looking for incremental improvements in cloud performance without the complexity of a full refactor.
• Ideal for application that can benefit from specific cloud optimization , such as using AWS – manage database , caching system , or auto – scale infrastructure .

advantage :

• Leverages cloud efficiencies without the complexity and cost of a full refactor.
• Reduces operational overhead by using managed services.
• Improves performance and scalability.

tool : AWS elastic beanstalk , AWS RDS , Amazon EC2 Auto Scaling , AWS Lambda .

3. Repurchase (Drop and Shop)

Definition: Repurchasing refers to abandoning an existing application and switching to a cloud-native, often SaaS (Software-as-a-Service) solution. For example, migrating from an on-premises CRM to a cloud-based SaaS CRM like Salesforce on AWS.

When to use :

• Suitable when the current application does not meet business needs, or the cost of re-architecting it outweighs the value of adopting a new cloud-based solution.
• Often used for applications where there are already mature SaaS offerings available that can provide better functionality, lower cost, or ease of use.

advantage :

• Simplifies operations as the responsibility for management shifts to the SaaS provider.
• Provides access to modern, cloud-based features, security, and scalability.
• Faster time-to-value by adopting ready-made solutions.

example :

• switch from an on – premise ERP system to a cloud – base ERP like SAP s/4hana on AWS .
• Moving to AWS Marketplace solutions for specific business needs.

4. Refactor/Re-architect

Definition: Refactoring or re-architecting involves rethinking the entire application architecture to take full advantage of cloud-native features like microservices, serverless computing, and containerization. This often involves significant changes in the codebase, database structure, and infrastructure design.

When to use :

• Ideal when the application has issues with scalability, performance, or when the existing architecture is outdated.
• Best for applications that require a cloud-first or cloud-native design to optimize for cost, agility, and future growth.
• Suitable for digital transformation projects where innovation, competitive advantage, and business agility are key drivers.

advantage :

• Maximizes the use of cloud-native features like elasticity, serverless architecture, and managed services.
• Offers the greatest long-term benefits in terms of performance, scalability, cost savings, and agility.
• Reduces technical debt by adopting modern architecture principles (microservices, event-driven design).

Challenges: High effort, cost, and time investment due to significant redevelopment.

Tools: AWS Lambda, AWS Fargate, Amazon EKS (Kubernetes), Amazon S3, Amazon DynamoDB, AWS Step Functions.

5. Retire

Definition: Retiring involves decommissioning applications that are no longer needed or relevant. As organizations go through the migration process, they often identify applications that have little to no business value, and it’s more efficient to retire these rather than migrate them.

When to use :

• Suitable for legacy applications that have been replaced or whose functionality is no longer required.
• use when the application is cause technical debt or operational overhead with little benefit .
• good for simplify the application portfolio .

advantage :

• Reduces maintenance costs and complexity.
• free up resource for more critical application and modern infrastructure .

process : perform a portfolio analysis to identify underutilized or obsolete application before migration .

6 . retain ( revisit )

Definition: Retaining or revisiting refers to keeping certain applications on-premises or in their current state because they are not suitable for migration at the moment. This can be due to compliance, latency requirements, or technical limitations that make moving them to the cloud difficult or impractical.

When to use :

• Appropriate when the application still provides business value but is not cloud-ready.
• Suitable for workloads that must remain on-premises due to regulatory requirements, data residency laws, or latency-sensitive applications.
• Used when an application will be re-evaluated for migration in the future.

advantage :

• Ensures critical workloads remain operational without taking on migration risk.
• Provides time for the organization to plan for future migration when the business case improves.

example : Legacy mainframe system that require specialized hardware or application with extreme low – latency requirement .

7. Relocate

definition : Relocating is is is the process of move application to another environment , such as an AWS region or AWS Outposts ( for on – premise cloud service ) . Relocating is change does n’t change the application ’s architecture but simply shift it to a different AWS location .

When to use :

• Appropriate when companies want to maintain an on-premises presence but use AWS-managed infrastructure, such as AWS Outposts, for compliance or latency-sensitive workloads.
• Ideal for businesses operating in hybrid cloud environments, where some workloads are in the cloud and others on-premises.

advantage :

• Provides flexibility to use cloud services in locations where AWS public cloud regions may not be suitable.
• enable low – latency access for on – premise application by bring AWS infrastructure on – site .

tool : AWS Outposts , AWS Direct Connect , AWS Local Zones .

conclusion

The 7 Rs of AWS Cloud Migration provide a flexible framework for planning cloud migrations, allowing businesses to select the best strategy based on their application requirements, cloud readiness, and business priorities. Each strategy has its unique advantages and use cases, ensuring that organizations can tailor their cloud journey for both short-term gains and long-term optimization.