Comprehensive Guide to R Strategy and The 7Rs of Cloud Migration

Cloud migration is one of the most critical decisions a business can make. The right cloud migration strategy can save your business time and money, while the wrong strategy can be costly and inefficient. This blog post will discuss the R strategy and the 7Rs of cloud migration that will enable you to reap the benefits of cloud computing. We will provide an overview of each option, how it can be applied to different workflows, and explain how it can help your business achieve its goals. Let’s get started!

Migration Strategies and Their Importance

Cloud migration strategies are designed to enable businesses to get the most out of their efforts, putting the right resources in place and preparing for any potential risks. Every cloud migration needs to be well-planned out, with carefully designed cloud migration steps, and managed throughout the entire process if it is to be successful.

A cloud migration strategy outlines the steps necessary for that to become a reality, covering everything from initial assessment and planning to data transfer and support. The R strategy umbrella of cloud migration plans is one of the most popular. It offers clear workflow assessment and direction for businesses to follow when moving their applications and data online.

The 7RS of Cloud Migration by AWS Cloud

Any R strategy will either be one of the current 7Rs, the 6Rs strategy of AWS migration from which the former emerged, or the earlier 5Rs strategy published by Gartner in 2010.

The latter consists of Rehost, Refactor, Revise, Rebuild, and Replace. This approach was adopted and extended by AWS cloud to Rehost, Replatform, Repurchase, Refactor, Retain, and Retire, with Relocate later added as the 7th R.

Relocate – Switching Locations

Used to transfer one or several applications on multiple servers, either from an on-premises platform to a cloud version of it or from one cloud environment to another. Relocating workloads in this way doesn’t require the purchase of any new hardware, code to be rewritten, or current operations modified.

Common Use Cases for the Relocate Strategy

• Transferring multiple servers from on-premises (e.g., VMware) to its cloud platform version (e.g., VMware Cloud on AWS Cloud).
• Migrating current workloads to another virtual private cloud (VPC), account, or region (e.g., from an Amazon Relational Database Service to a different VPC).

Benefits of Relocating Workloads

• Minimal downtime and disruption, since users continued to be served during the migration process.
• Migration costs are reduced and predictable, since no new hardware or staff training is required.

Disadvantages of Relocating Workloads

• Potential performance issues, as relocating workloads does not optimize them for the cloud.
• Continued maintenance and compatibility with existing applications on the new platform can use time and resources.

Rehost – Lift and Shift

The process of moving existing applications in the cloud without making any changes or updates to the existing code or core architecture. It’s useful for businesses who don’t have time or resources to redevelop their applications for a cloud environment, allowing them to quickly move their apps online and take advantage of cloud benefits.

Common Use Cases for the Rehost Strategy

• Moving an application stack from on-premises to the cloud (e.g., Oracle database to Amazon RDS), which can be automated with, for example, AWS Server Migration Service.
• Migrating multiple machines from various source platforms (e.g., virtual, physical, or different cloud environments).

Benefits of Rehosting Workloads

• Minimizes issues concerning compatibility, disruption, long migrations, or long-distance data replications.
• Scale applications without having to implement any time and cost-saving cloud optimizations.
• Easier to integrate, for example, AWS services and, therefore, to optimize or re-factor applications once they have been rehosted to the cloud.

Disadvantages of Rehosting Workloads

• Non-scalability of legacy applications means they don’t take full advantage of cloud-based capabilities.
• Lack of modification or optimization for the cloud can cause migrated applications to suffer from performance and/or other issues.
• The migration process may fail if the application requirements aren’t mapped out accurately to the corresponding cloud configuration, while any existing problems will carry an increased risk.

Replatform – Lift and Reshape

Optimizing an application during the process of migrating it to a cloud platform in order to take full advantage of its features to improve performance or reduce costs. It’s less disruptive than refactoring, which will be discussed below, and allows better optimization for the target platform.

Common Use Cases for the Replatform Strategy

• Upgrading an operating system (OS) to the latest version without any code changes (e.g., migrating legacy Windows Server applications to the latest, supported versions in the cloud).
• Moving an application to a fully managed platform.
• Migrating virtual machines into containers (e.g., modernizing .NET or Java applications into containerized Docker or Kubernetes applications).

Benefits of Replatforming Workloads

• Keeps legacy applications running without security or compliance being compromised.
• Improves performance and reduces costs while avoiding licensing expenses.
• Reduces how long one would spend managing database instances.
• Maximizes ROI by improving application agility, resilience, and flexibility thanks to the modernization of select components enabling cloud-native features (e.g., CI/CD pipeline automation, cloud services, infrastructure as a service approach (IaaS)).

Disadvantages of Replatforming Workloads

• The work scope can creep into refactoring if not managed correctly to prevent any unnecessary changes.
• Necessary to use common rather than specialized cloud components, which tend to require unworthwhile, dramatic changes to the application.
• Some investment in at least basic automation and slight refactoring is required to provide some flexibility, else replatforming will be severely limited.

Repurchase – Replace Drop and Shop

Replacing an application with another version or a different product entirely that provides more business value. Typically, the repurchased application will take advantage of cloud features like from-anywhere accessibility, whilst having an infrastructure that is maintenance free on the client’s side and pay-as-you-go pricing.

Common Use Cases for the Repurchase Strategy

• Moving to a Software as a Service (SaaS) license.
• Replacing applications with the latest version from the vendor or a third-party, cloud-based equivalent.
• Avoiding the need to recode or re-architect an application by repurchasing a SaaS or cloud-based one.

Benefits of Repurchasing Workloads

• Reduces an existing application’s licensing, infrastructure, and maintenance issues and costs.
• Integrating with cloud services allows for leveraging new features and scaling the application more easily.

Disadvantages of Repurchasing Workloads

• The costs can accumulate, particularly if repurchasing multiple applications.
• Having to find an application that meets strong business requirements, especially those concerning compliance and security, but also switching to products that might not fully resemble your current processes.
• The need to train users and teams with the new system takes time, and resources, and further adds to the costs.
• Not an ideal option for feature-rich or greatly customized specialist applications.
• Provider lock-in, it won’t be easy to make the switch if the SaaS solution you pick won’t match your needs.

Refactor – Re-writing and Decoupling Applications

The re-architecture of applications from the ground up in order to gain cloud-native capabilities that allow for greater performance, agility, and scalability without having to fully re-write. It addresses the need to scale and improve business continuity, or release products and features faster, when it would be hard to do so in the application’s existing environment.

Common Use Cases for the Refactor Strategy

• Legacy or monolith application migration whose source code isn’t available, or no one knows how to maintain it, is slowing down product delivery, or can no longer address business needs or customer demands due to its limitations or cost.
• A refactoring journey is also selected when you want to migrate legacy applications to the cloud with a target to update or add features that will support your business case better and boost agility.
• Moving to a service-oriented architecture.
• Redesigning an application for the cloud to make testing easier by integrating automated tools and/or increasing test coverage.
• Refactoring a database to separate and extract some tables that need to be kept on premises (e.g., customer profiles) from those that will undergo cloud migration.

Benefits of Refactoring Workloads

• High ROI thanks to scalability, reducing consumption of resources (and therefore costs) by aligning the cloud infrastructure with the requirements.
• Allows businesses to quickly adapt to changing customer demands thanks to the ability to easily add new features to or modify existing ones of cloud-native architectures.
• Personalized levels of automation and high availability are offered as a result of wiring together managed solutions from de-coupled application components.
• Application migration strategy based on heavy refactoring enables true digital transformation and prepares businesses for novel strategies and technologies (e.g., big data analysis, and machine learning applications).

Disadvantages of Refactoring Workloads

• Applications can become locked into certain public cloud providers due to reliance upon cloud-native features.
• Extensive planning is required to prevent making mistakes at the code or infrastructure level that could cause delays, downtime, and/or increased costs.
• Requires thorough training of existing staff, as well as cloud expertise in the form of advanced coding, automation, and DevOps skills.
• Migration is complex, time-consuming, and requires many resources and constant monitoring, meaning it can take longer than other cloud migration strategies to yield a satisfying ROI.
• Not the best option if planning to migrate a large number of applications all at once.

Retain – Keep Services As Is

Migration strategy for keeping an existing application as is on-premises until a possible later date or after thorough planning. This may be due to security and compliance requirements, dependencies on other applications that require prior migration or physical hardware with no cloud equivalent, or lack of business value in migrating.

Common Use Cases for the Retain Strategy

• Postponing migration of an application that has recently been upgraded.
• Retaining a vendor-based application until the cloud provider releases a SaaS version.
• Conducting a careful assessment of mainframe or mid-range (e.g., Oracle Solaris OS for operating on Oracle Database) and non-x86 Unix applications before cloud migration.

Benefits of Retaining Workloads

• Allows for evaluation of (recently upgraded) applications in order to identify those that require immediate migration or those that could be migrated in the future.
• Saves cloud resources by retaining inefficiencies on-premises.

Disadvantages of Retaining Workloads

• Lack of cloud-native capabilities, meaning no automated scaling or improved performance.
• Requires costly and continuous maintenance of the on-premises hardware.

Retire – Turn Services Of

Decommissioning or archiving an application, allowing the servers within its application stack to be shut down. Possible reasons for retiring an application are to save on its hosting and maintenance costs, reducing the security risks of an unsupported OS or components thereof, or, again, lack of business value in migrating it to the cloud.

Common Use Cases for the Retire Strategy

• Retiring a redundant or legacy application that is no longer in use.
• Turning off a service that has average CPU and memory usage of less than 5% (i.e., a zombie application) or 5-20% in any 90-day period (i.e., an idle application) or to which no inbound connection has been made in that time.

Benefits of Retiring Workloads

• Minimal investment in time, money, and effort is required.
• Reduces expenditure on idle resources.

Disadvantages of Retiring Workloads

• Retiring applications prematurely or without proper planning can cause compatibility issues.

How to Choose the Right R Strategy for Your Applications

The right choice between Relocating, Rehosting, Replatforming, Repurchasing, Refactoring, Retaining, or Retiring an application will depend on its size and complexity, hardware requirements, scalability and availability requirements, technical compatibility with the cloud infrastructure, and the company’s budget, among other factors.

In any case, a well thought-out migration strategy will play a key role in successful cloud migration, reducing the risk of issues and cloud migration challenges along the way and increasing ROI. If you can’t decide which of the 7Rs of cloud migration is best for your applications, it’s worth consulting with cloud engineering experts like those at nexocode, who can help you determine the best course of action and architect custom migration strategies. Contact us, and get started with your cloud journey.

References

Migration Strategies from AWS Cloud