Evaluating applications according to the seven common migration strategies (7Rs)

Can you name and briefly describe the seven common migration strategies used for moving applications to AWS?

The seven common migration strategies, also known as the 7Rs, include:

• Rehosting (“Lift and shift”): Moving applications to AWS without making changes.
• Replatforming (“Lift, tinker and shift”): Making slight modifications to applications to take advantage of cloud capabilities without major changes.
• Repurchasing (“Drop and shop”): Moving from a traditional license to a cloud-native product, such as switching from a CRM to Salesforce.
• Refactoring / Rearchitecting: Making significant changes to the application’s architecture to fully exploit cloud-native features and performance.
• Retire: Identifying IT assets that are no longer useful and can be turned off.
• Retain: Keeping applications in the current environment that are not ready for cloud migration.
• Relocate: Moving applications to the cloud without changes, but with a focus on infrastructure. This is typically used in combination with VMware Cloud on AWS.

What are the main factors that would influence an organization to choose the “Rehost” strategy over others during migration to AWS?

The main factors include:

• A large scale migration scenario where speed and simplicity are crucial.
• Licensing constraints that do not allow for significant changes to the application.
• The need to quickly vacate a data center due to cost or contract expiration.
• Lack of in-house skills to perform a more complex migration initially.
• The desire to postpone major application changes until after the applications are running in AWS.

What is a key advantage of choosing “Refactoring/Rearchitecting” as a migration strategy, and what type of application would most benefit from this approach?

A key advantage of refactoring/rearchitecting is that it allows organizations to fully leverage AWS capabilities for better scalability, agility, and cost efficiency. Applications that would most benefit are those with scalability issues, or those requiring significant modernization, or that are strategically important and could benefit from cloud-native features like serverless computing, microservices architecture, and managed services.

Why might an organization opt for the “Retire” strategy as part of their cloud migration journey?

Organizations may opt for the “Retire” strategy when they find IT assets that are no longer useful and can be decommissioned. This reduces complexity and cost by removing unnecessary components as they transition to the cloud.

What considerations need to be taken into account when selecting “Repurchasing” as a migration strategy?

When selecting “Repurchasing,” organizations should consider:

• The compatibility of the new product with existing workflows and systems.
• The potential disruption to business operations during the transition.
• The costs associated with transitioning to a new licensing model.
• Any training requirements for staff to use the new platform.
• Improved features and capabilities that the cloud-native product may offer over the existing solution.

In which scenario would “Replatforming” be a more appropriate migration strategy than “Refactoring”?

“Replatforming” would be more appropriate when the organization aims to gain some benefits from the cloud, such as performance improvements or cost savings, but doesn’t want to invest in the more extensive changes that refactoring requires. A simple example might be modifying the application to move from a self-managed database to a managed service like Amazon RDS.

Can you discuss a scenario where the “Retain” strategy is the best approach for an organization?

The “Retain” strategy is best when certain applications or components have strict compliance or regulatory requirements, if they are tightly coupled to physical hardware, or if the organization has made recent investments in on-premises technology. In such cases, it might be best to keep these systems on-premises until the regulatory landscape changes or the investments are amortized.

How does the “Relocate” strategy differ from “Rehosting,” and what is a common use case for “Relocate”?

The “Relocate” strategy differs from “Rehosting” in that it’s primarily used with infrastructure that can be moved wholesale, like VMware Cloud on AWS. A common use case is moving entire VMware workloads to the cloud without modifications, leveraging the hybrid cloud environment.

What kind of preparation is necessary for an organization to successfully implement the “Repurchasing” strategy for a critical business application?

Necessary preparations include:

• Performing a thorough evaluation of potential products and vendors.
• Ensuring that the new product integrates with existing systems.
• Training employees on the new product.
• Planning the migration to minimize downtime and mitigate risks.
• Developing a data migration strategy that ensures no data loss or corruption.
• Planning for a period of running both old and new systems in parallel.

Can you explain some of the cost implications and potential savings when an organization decides to “Retire” certain IT assets during cloud migration?

Retiring IT assets can result in direct cost savings by eliminating expenses related to maintenance, support, and licensing fees for those assets. It can also reduce indirect costs by simplifying the environment and enabling staff to focus on strategic initiatives rather than maintaining obsolete technology.

What risks or challenges might a company face when choosing to “Refactor/Rearchitect” an application for the cloud, and how can these be mitigated?

Risks include:

• Longer lead times and increased cost compared to simpler strategies.
• The potential for disruptions to business operations during the transition.
• Challenges in acquiring or developing the necessary skills within the team.

Mitigation strategies include:

• Incremental refactoring of the application to reduce risk.
• Implementing strong project management and DevOps practices.
• Training or hiring staff with the required skills.
• Engaging with professional services or obtaining guidance from AWS architects.

Which migration strategy would be most suitable for an application that is heavily dependent on a legacy operating system that cannot be supported in the cloud?

The most suitable migration strategy for such an application would likely be “Retain” because the application cannot easily be moved to the cloud due to the legacy operating system dependency. Alternatively, if the application is vital and must be modernized, “Refactoring/Rearchitecting” may be considered, albeit with a potentially significant effort and cost.

Please note that some of the AWS services and strategies might evolve over time, so it’s crucial to stay updated with the latest best practices and service offerings from AWS for the AWS Certified Solutions Architect – Professional exam.