What is a Cloud Migration Strategy?
Migrating to the cloud offers many benefits, including increased performance and scalability, reduced operational costs, and increased resiliency. The cloud expedites business opportunities and technical outcomes while reducing business risks through improved governance and security.
However, migrating to the cloud isn’t a simple “transfer and switch on” process. Common cloud migration challenges include:
- Executive support and other stakeholder buy-in
- Discrepancies between infrastructure types
- Cloud provider configuration difficulties
- New systems to learn.
- Security and cost management considerations in transfer and configuration
- Determining hybrid needs between on-prem and cloud resources.
A cloud migration strategy is a documented plan created by an organization that provides the roadmap for shifting from its current infrastructure to a new cloud version. A successful cloud migration strategy is imperative for ensuring continuous business operations. Beyond that, planning is necessary to implement a highly efficient cloud architecture at low costs for future scaling and integrability.
What are key considerations for a cloud migration strategy?
A solid cloud migration strategy will help get you up and running with as little disruption to business operations as possible and without any unexpected challenges. It begins by first identifying the right cloud capabilities and configurations in the cloud infrastructure of your choice. Also, factor in the following:
Security and compliance requirements
Conduct security assessments before migration to identify potential risks and vulnerabilities. A well-defined governance framework will help enforce policies and ensure compliance throughout the transition.
Automation and migration tooling
Leveraging automation reduces manual effort and minimizes migration risks. It also assists with infrastructure as code (IaC), ensuring configurations remain consistent across environments. Organizations should assess the proper tooling to optimize their migration speed and reliability. The AWS Migration Hub is a good place to start your cloud migration discovery journey.
Training for migration and post-migration operations
A successful cloud transition depends on the readiness of IT teams and end-users. Training programs should cover new cloud technologies, security protocols, and operational best practices. You should also establish a knowledge base and ensure ongoing support and documentation.
Scheduling and timelines
A phased migration approach helps minimize business disruptions. You can create a migration timeline that prioritizes critical workloads first while maintaining operational continuity. Your cloud migration plan should also schedule decommissioning of legacy infrastructure. This includes retiring unused servers, canceling redundant licenses, and ensuring data is securely archived or deleted. You may have to allow sufficient time between migration and decommissioning so everyone gets comfortable with the new infrastructure.
Incremental transformation and ongoing optimizations
Cloud adoption requires an incremental transformation strategy rather than a one-time shift. Gradually modernizing applications reduces risks and allows teams to adjust to new cloud environments. Over time, you can leverage auto-scaling, reserved instances, and rightsizing techniques to minimize expenses. Regular monitoring ensures that cloud resources are used efficiently.
What are the main cloud migration strategies?
Different resources require different approaches to migration. There are seven migration strategies for moving applications to the cloud, known as the 7 Rs.
Retire
This strategy is used when the resource is no longer needed. You can choose to decommission or archive the resource in this case. It simply means turning off servers for applications that are no longer required. Retire when there is no business value in moving an application to the cloud, it uses legacy technology that is no longer supported, and it is more cost-efficient to turn it off.
You can identify such applications by analyzing their average CPU and memory consumption. Applications with consumption below 5 percent can be retired straight away. Applications with consumption between 5 and 20 percent may also be considered, especially if they have no inbound requests over 90 days.
Retain
This strategy involves keeping a resource as-is without migrating to the cloud. This may be due to security reasons, a lack of value-add, physical dependencies, or other complex considerations. For example, you can postpone migrating an application whose infrastructure was recently upgraded with significant investment. Alternatively, you might retain a third-party application until the vendor releases a SaaS version.
Rehost
The rehosting cloud migration strategy is the “lift-and-shift” approach. For example, you can migrate a physical server’s configuration and workloads to the same server in the cloud environment. You can migrate machines from multiple sources to the AWS Cloud without worrying about performance disruption, compatibility, long-distance data replications, or long cutover windows.
Relocate
The relocate strategy moves infrastructure from one environment to another. It is used when the cloud infrastructure has mappings that are equivalent to your existing resources—for example, migrating VMware SDDC to VMware Cloud on AWS. You can also use it to reconfigure existing cloud infrastructure. Within AWS, this may mean moving instances or objects to a different AWS account, region, or virtual private cloud (VPC). For example, you transfer an Amazon RDS DB instance to another AWS account.
Repurchase
Repurchase, or “drop and shop,” involves moving from a current application or infrastructure to a different product. Use cases include moving from an on-premise license to a SaaS license, replacing an application with a similar cloud product, or replacing a custom application with an out-of-the-box cloud solution. Before purchasing, assess the new application according to business requirements, especially security and compliance.
Replatform
The replatform strategy is “lift, tinker, and shift” or “lift and reshape.” It involves reconfiguring an application or infrastructure component and optimizing it in some way for the cloud. It keeps your legacy application running without compromising security. At the same time, you can reduce costs and improve performance by moving virtual machines to containers, migrating to a managed or serverless service, or moving from one operating system to another.
For example, you might re-platform a Microsoft SQL Server database to Amazon RDS for SQL Server or migrate ML workloads to Amazon SageMaker.
Re-architect
The re-architect strategy goes beyond re-platforming by changing the architecture of an application or infrastructure to take advantage of cloud-native features. If you have a legacy application with a monolithic design, poor test coverage, or outdated code that is becoming harder to maintain, consider refactoring. Depending on the application, you may consider reusing some code areas while changing others or redesigning from scratch. Rearchitecting can be a long process that requires both cloud and engineering expertise.
What is the cloud migration process?
The cloud migration process goes beyond current and target technologies to cover all facets of organizational change management. It includes the following three steps:
Step 1—Assess
Before migrating to a cloud environment, you must assess your readiness to ensure the best chance of transformational success. The AWS Cloud Adoption Framework (CAF) considers cloud migration readiness across six perspectives: business, people, governance, platform, security, and operations.
You must also assess your organization’s application portfolio to understand how to migrate and modernize your apps. Complex infrastructure, integrations, security, and identity considerations support existing applications. An application portfolio assessment identifies key stakeholders and data sources and helps with application migration priorities.
You can use the AWS Cloud Readiness Assessment to self-assess your organization’s cloud readiness. AWS also offers a free migration assessment in which our team evaluates and scores your organization across several verticals, including detailed business cases, operations, security, people, and more.
We help you discover the specific areas where your organization has readiness gaps. By working to close these gaps, you can improve your chances of a successful migration program.
Step 2—Mobilize
The mobilize phase involves migration planning and choosing the best migration strategies for your current environment based on your cloud providers’ target architecture. Tasks include, but are not limited to:
- Prioritization of migration resources.
- Development of migration targets such as speed, downtime, and operational capacity.
- Staff training for migration and post-migration service management and operations.
- Creation of target architectures and services
- Test of the migration environment with smaller or less critical applications or services
Using an architectural decision record (ADR) during the mobilize phase is strongly recommended. This living document covers each architectural decision and the reasoning behind the choice.
For instance, many organizations choose to refactor or retain a legacy software system. Refactoring can be lengthy and costly but typically delivers ROI after several years. How an application is refactored also affects these calculations. An ADR can explain how the refactored structure, dependencies, interfaces, and construction techniques deliver the same (or better) performance and reduce the cost of ownership over time.
Step 3—Migrate and modernize
The migration process itself depends on the size and requirements of your organizational shift. Smaller or simpler migrations may roll out one by one using readily available tools without repeatable patterns or automatable commonalities. Larger or more complex migrations require emerging patterns spanning multiple applications, infrastructure elements, organizational areas, or projects.
AWS offers several migration tools, such as the AWS Application Discovery Service and the AWS Database Migration Service, to support complex migrations. You can also consider building migration factories to conduct large cloud migration activities. A migration factory is a collection of concurrently operating teams, with specific teams conducting rehosting, re-platforming, and refactoring migrations. Refactoring teams typically work similarly to software development teams, with DevOps-style support.
Developing automation plans, processes, and tooling based on an initial migration helps speed the cloud migration process across the organization.
How can AWS support your cloud migration strategy?
With AWS cloud services, you can leverage your existing data and applications to scale and grow with AI and beyond from a strong foundational cloud provider. Selecting the right cloud migration strategies is critical to your program’s success. Whether you are considering cloud migration or are ready to start shifting your resources to the cloud, AWS provides guidance, assessment tools, and a range of partners to get started.
The AWS Migration Acceleration Program (MAP) (MAP) is a comprehensive and proven cloud migration program based on AWS's experience migrating thousands of enterprise customers to the cloud. MAP provides tools, tailored training approaches and content, expertise from Partners in the AWS Partner Network, a global partner community, and AWS investment. Consider MAP as your partner to automate and accelerate execution within budget.
Visit AWS Cloud Migration to migrate and modernize with AWS today.