The 7 Rs of Cloud Migration: 7 Strategies Explained

AWS has brought in the 7 Rs model, a detailed framework made to assess various migration strategies and offer customized solutions according to different workloads and business needs. In this blog post, we’ll look at the 7 Rs model closely, pointing out the advantages and practical applications of each strategy. This information will assist you in making well-informed choices when mapping out your cloud migration project.

History of the Rs for Cloud Migration 

The 5 Rs model was introduced by Gartner for evaluating migration strategies to the cloud. It became widely adopted, but AWS recognized the need for a more comprehensive framework and added a sixth R, Retire. The 6 Rs model offers a more complete and flexible approach to cloud migration, tailored to varying workloads and business requirements.

AWS 7 Rs Model

As cloud computing continued to mature, AWS introduced the 7 Rs model, representing the latest iteration of the migration framework. This version added the Retain strategy, acknowledging that not all applications and data can or should be moved to the cloud. The 7 Rs model provides organizations with more flexibility in their migration planning by offering the choice to keep workloads on-premises. This enables businesses to weigh the advantages of cloud computing against the need to retain control over crucial systems and meet regulatory requirements.

The 7 Cloud Migration Strategies in Detail

Exploring the “7 Rs” or cloud migration strategies, as per AWS’s expanded model based on the original “5 Rs” introduced by Gartner, provides a comprehensive understanding. The seven strategies, illustrated in the expanded 7 Rs model, form the foundation for effective cloud migration.

Rehost

The rehost migration strategy uses cloud Infrastructure-as-a-Service (IaaS) to move workloads onto a cloud instance. With this approach, organizations can shift on-premises applications and their related components to the cloud without making significant changes to the underlying infrastructure. With operational and configuration constructs remaining intact, the rehost strategy is easy to perform, making it suitable for enterprises lacking in-house cloud-native expertise.

Use-case:

• Suitable for organizations seeking a quick migration with minimal modifications.
• Ideal for applications with straightforward architecture and minimal dependencies.

Pros:

• Expedited migration process.
• Minimal disruption to operations.

Cons:

• Limited optimization and utilization of cloud-native features.
• Potential missed opportunities for efficiency gains.

Relocate 

A newly introduced strategy, relocating migrates workloads without affecting ongoing operations, rewriting application source code, or acquiring new hardware. This method seamlessly moves servers from on-premises platforms, such as Kubernetes or VMware, to a cloud version of the same platform. Minimizing downtime and disruption, the strategy doesn’t necessitate significant changes in workload configurations, reducing operating expenses.

Use-case:

• Appropriate for businesses with established virtualized environments.
• Useful when aiming to minimize downtime and disruption during migration.

Pros:

• Seamless migration without impacting ongoing operations.
• Effective for scenarios where significant modifications are impractical.

Cons:

• Restricted scalability due to clear limits during migration.
• May not leverage the full potential of cloud-native capabilities.

Replatform

The replatform strategy involves moving an application to the cloud while employing platform optimization to leverage cloud-native capabilities. This strategy retains the source code and core architecture, keeping legacy applications operational while ensuring compliance and security in a cloud-based environment. The replatform migration strategy enhances flexibility, agility, and resilience while enabling cloud-native capabilities such as automation.

Use-case:

• Beneficial when optimizing existing applications for cloud-native capabilities.
• Suitable for organizations aiming for enhanced flexibility and agility.

Pros:

• Retains core architecture while improving agility.
• Saves time and costs by modernizing without extensive code rewriting.

Cons:

• May not achieve the level of optimization seen in more extensive refactoring.
• Limited to enhancements within the existing architecture.

Refactor

Often considered the most complex migration option, refactoring entails re-architecting workloads to support cloud-native capabilities from the ground up. Despite requiring significant effort and resources, this approach is considered the most future-proof, allowing applications to support advanced features such as serverless computing, autoscaling, and distributed load balancing.

Use-case:

• Ideal for applications requiring advanced cloud-native capabilities.
• Suitable for organizations with a long-term vision for cloud infrastructure.

Pros:

• Future-proof migration approach.
• Enables support for serverless computing, autoscaling, and advanced features.

Cons:

• Requires significant investment in effort and resources.
• Complexity and potential high costs during the migration phase.

Repurchase

The repurchase migration strategy involves exchanging internally administered systems for third-party managed services available from the cloud provider. This shift to a SaaS subscription model simplifies migration, reducing downtime, enhancing scalability, and improving regulatory governance. Leveraging cloud-native capabilities, this strategy is commonly adopted for workloads requiring enhanced application performance and user experience while minimizing operational overheads.

Use-case:

• Appropriate for organizations looking to transition to a SaaS subscription model.
• Ideal for enhancing application performance and user experience.

Pros:

• Simplifies and expedites migration with third-party managed services.
• Ties IT costs to generated revenue with a consumption-based model.

Cons:

• Relies on external vendors, reducing control over infrastructure.
• May not be cost-effective for all workloads.

Retire

The retire strategy is employed when terminating or downsizing applications that are no longer useful in production. It plays a crucial role in retiring business-critical workloads operating on inefficient legacy frameworks, paving the way for the adoption of modern, cloud-native deployments.

Use-case:

• Necessary for retiring outdated and inefficient applications.
• A crucial step towards adopting modern, cloud-native deployments.

Pros:

• Reduces operational costs by eliminating obsolete applications.
• Streamlines and declutters the IT landscape.

Cons:

• Requires careful assessment to avoid unintentional elimination of still-relevant components.
• Potential resistance or challenges in retiring certain legacy applications.

Retain 

The retain strategy is suitable for applications that cannot be retired and should continue operating in their existing framework. Enterprises typically choose to retain a workload if it relies on another application that needs to be migrated first or when there is no immediate business value in migrating the application to the cloud. For vendor-based applications, an enterprise may also opt to retain if the service provider plans to eventually release a Software-as-a-Service (SaaS) model.

Use-case:

• Suitable for applications with dependencies or lacking immediate business value.
• Appropriate when migrating another application takes precedence.

Pros:

• Provides flexibility to retain applications in their existing framework.
• Allows enterprises to postpone migration until optimal conditions arise.

Cons:

• Delays the realization of cloud benefits for retained applications.
• Continuous assessment is needed to determine the optimal timing for migration.

Conclusion:

AWS’s 7 Rs model provides a comprehensive framework for evaluating cloud migration strategies. Every strategy comes with its strengths and weaknesses, and organizations need to pick the one that aligns best with their business needs. By grasping the advantages and practical applications of each strategy, organizations can make well-thought-out decisions while planning their cloud migration projects, guaranteeing a seamless transition and long-term cloud success.