Migrating Applications to AWS: A secret guide

Cloud migration involves the process of moving applications, data, and other business elements from on-premises infrastructure to cloud-based environments. Among the leading cloud service providers, Amazon Web Services (AWS) stands out as a top choice for organizations worldwide due to its robust infrastructure, extensive service offerings, and proven track record.

In this article, we will explore the significance of cloud migration, delve into the benefits of migrating applications to the AWS cloud, examine various migration strategies, outline the migration process recommended by AWS, explore real-world migration scenarios, and conclude with valuable insights and resources for embarking on your own migration journey with AWS.

Why Cloud Migration Matters

Cloud migration is integral to modern business strategies for several reasons. Firstly, it enables organizations to achieve greater scalability and elasticity, allowing them to swiftly adapt to changing workloads and user demands. Unlike traditional on-premises infrastructure, cloud environments can dynamically allocate resources as needed, ensuring optimal performance and cost-efficiency.

Secondly, migrating applications to the AWS cloud offers enhanced security features and compliance capabilities. AWS adheres to stringent security standards and provides a range of tools and services to help customers protect their data and applications from cyber threats and unauthorized access.

Additionally, cloud migration promotes cost-efficiency by reducing capital expenditures on hardware and maintenance. With pay-as-you-go pricing models and the ability to scale resources up or down based on usage, organizations can optimize their IT spending and allocate resources more effectively.

Moreover, migrating applications to the cloud enhances flexibility and agility, empowering teams to innovate and iterate at a faster pace. By leveraging AWS’s extensive portfolio of services, developers can rapidly deploy, test, and iterate on applications, accelerating time-to-market and driving business growth.

Migration Strategies

When embarking on a cloud migration journey, organizations must carefully consider the most suitable migration strategy based on their unique requirements, constraints, and objectives. AWS recommends six common migration strategies, each with its own set of pros and cons:

  1. Rehosting (Lift and Shift): This strategy involves migrating applications to the cloud with minimal modifications, essentially replicating the existing infrastructure in AWS. While rehosting offers a quick and straightforward migration path, it may not fully leverage the benefits of cloud-native services and architectures.
  2. Replatforming (Lift, Tinker, and Shift): Replatforming entails making some optimizations to the application or underlying infrastructure while moving it to the cloud. This approach allows organizations to take advantage of cloud-native features and improve performance and scalability without the need for a complete overhaul.
  3. Repurchasing (Drop and Shop): In some cases, it may be more advantageous to replace an existing application with a cloud-native solution or a third-party SaaS (Software as a Service) offering. While this strategy can lead to significant long-term benefits, it may require substantial upfront investment and disrupt existing workflows.
  4. Refactoring (Re-architect): Refactoring involves re-architecting the application to leverage cloud-native services and architectures fully. Although refactoring requires more time and resources upfront, it can result in significant performance improvements, cost savings, and scalability benefits in the long run.
  5. Retiring: If an application is no longer needed or relevant to the business, retiring it may be the most prudent course of action. By decommissioning obsolete or redundant applications, organizations can streamline their IT infrastructure and reduce maintenance costs.
  6. Retaining: In some cases, certain applications may not be suitable for migration due to technical constraints, compliance requirements, or cost considerations. In such scenarios, organizations may opt to keep these applications on-premises while migrating other workloads to the cloud.

Each migration strategy has its own set of trade-offs, and the optimal approach will vary depending on factors such as application complexity, business objectives, budget constraints, and timeline considerations. Let’s explore each strategy in more detail, along with examples of common use cases:

  • Rehosting (Lift and Shift): Rehosting is often favored for legacy applications that are well-suited to run in virtualized environments with minimal dependencies. By migrating these applications to AWS using services such as Amazon Elastic Compute Cloud (EC2) and Amazon Simple Storage Service (S3), organizations can achieve rapid migration with minimal disruption to existing workflows. For example, a company may choose to rehost its legacy ERP (Enterprise Resource Planning) system to AWS to improve scalability and reduce infrastructure maintenance costs.
  • Replatforming (Lift, Tinker, and Shift): Replatforming is ideal for applications that require some optimization to fully leverage the benefits of cloud infrastructure. For instance, an e-commerce platform may migrate its database to Amazon Aurora, a fully managed relational database service, to improve performance, scalability, and availability while maintaining compatibility with existing applications. By replatforming selective components of the application stack, organizations can achieve significant performance gains without the complexity of a complete overhaul.
  • Repurchasing (Drop and Shop): Repurchasing is commonly chosen for applications that have equivalent or superior cloud-native alternatives available in the market. For example, a company may replace its on-premises email server with Amazon WorkMail, a managed email and calendaring service, to simplify administration, enhance security, and reduce infrastructure overhead. While repurchasing may require upfront migration costs and training for end users, the long-term benefits of adopting a cloud-native solution can outweigh the initial investment.
  • Refactoring (Re-architect): Refactoring is typically reserved for applications that require significant architectural changes to fully exploit the benefits of cloud-native architectures and services. For instance, a monolithic application may be refactored into a microservices-based architecture deployed on Amazon Elastic Kubernetes Service (EKS) to improve scalability, agility, and fault tolerance. While refactoring entails more upfront effort and investment, it enables organizations to unlock the full potential of cloud computing and drive innovation at scale.
  • Retiring: Retiring applications that are obsolete, redundant, or no longer aligned with business objectives can streamline IT operations and reduce maintenance costs. For example, a company may decommission legacy applications that have been replaced by more modern, cloud-native alternatives or integrated into broader platforms. By retiring obsolete applications, organizations can free up valuable resources and focus on strategic initiatives that drive business value.
  • Retaining: In certain cases, organizations may choose to retain certain applications on-premises due to technical constraints, compliance requirements, or cost considerations. For example, applications with strict regulatory compliance requirements or specialized hardware dependencies may be better suited to remain on-premises rather than migrating to the cloud. By carefully evaluating the suitability of each application for migration, organizations can develop a tailored migration strategy that maximizes the benefits of cloud computing while minimizing risks and disruptions.

Migration Process

A successful cloud migration requires careful planning, execution, and ongoing optimization to ensure a seamless transition and maximize the benefits of cloud computing. AWS recommends a three-phase migration process consisting of assessment, mobilization, and migration/modernization:

  1. Assessment: The assessment phase involves evaluating the current state of the application portfolio, identifying suitable candidates for migration, and developing a comprehensive migration strategy. During this phase, organizations should conduct a thorough analysis of each application’s architecture, dependencies, performance characteristics, and business requirements to determine the most appropriate migration approach.


Example Use Case: A company wants to migrate its legacy CRM system to the AWS cloud to improve scalability and availability. By rehosting the application, the company can quickly move its existing infrastructure to AWS EC2 instances without making significant changes to the underlying architecture.


  • Quick and straightforward migration process
  • Minimal disruption to existing workflows
  • Lower upfront investment compared to other migration strategies


  • Limited optimization and scalability benefits
  • May not fully leverage cloud-native features and services

Replatforming, also known as “lift, tinker, and shift,” involves making some optimizations to the application during migration, such as upgrading to a newer version of the operating system or database. This approach strikes a balance between speed and optimization, offering benefits such as improved performance and reduced operational overhead.

Example Use Case: A company wants to migrate its e-commerce platform to the AWS cloud to handle increasing traffic and improve performance. By replatforming the application, the company can upgrade its database to a managed service like Amazon RDS while keeping the rest of the architecture intact.


  • Improved performance and reliability
  • Reduced operational overhead
  • Better alignment with cloud best practices


  • Requires additional planning and testing compared to rehosting
  • May involve some downtime during the migration process

Repurchasing involves replacing the existing application with a cloud-native alternative, such as migrating from an on-premises CRM system to a SaaS solution like Salesforce. This approach offers benefits such as reduced maintenance costs, automatic updates, and access to advanced features.

Example Use Case: A company wants to modernize its HR management system and migrate to a cloud-native solution to improve scalability and flexibility. By repurchasing the application, the company can leverage a SaaS platform like Workday, which offers built-in scalability and regular updates.


  • Reduced maintenance costs
  • Access to advanced features and functionality
  • Automatic updates and scalability


  • Limited customization options compared to on-premises solutions
  • Data sovereignty and security concerns

Refactoring, also known as “re-architecting,” involves redesigning and rebuilding the application to leverage cloud-native features and services fully. This approach offers maximum benefits in terms of scalability, performance, and cost-efficiency but requires significant time and resources.

Example Use Case: A company wants to modernize its monolithic application architecture and migrate to a microservices-based architecture on the AWS cloud. By refactoring the application, the company can break it down into smaller, independently deployable services, allowing for better scalability and agility.


  • Maximum scalability and performance benefits
  • Greater flexibility and agility
  • Cost optimization through efficient resource utilization


  • Requires significant time, resources, and expertise
  • Potential disruptions to existing workflows

Retiring involves decommissioning applications that are no longer needed or useful, thereby reducing complexity and cost. This approach helps organizations streamline their IT infrastructure and focus resources on core business activities.

Example Use Case: A company wants to streamline its application portfolio and reduce maintenance costs by retiring legacy applications that are no longer in use. By decommissioning these applications, the company can free up resources and simplify its IT environment.


  • Reduced maintenance costs
  • Simplified IT environment
  • Focus on core business activities


  • Potential data migration challenges
  • Impact on users accustomed to the retired applications

Retaining involves keeping certain applications on-premises if they are not suitable for migration due to regulatory constraints or technical limitations. This approach allows organizations to maintain control over sensitive data and comply with industry regulations.

Example Use Case: A financial services company wants to migrate its customer data to the cloud but must comply with strict regulatory requirements regarding data sovereignty and privacy. By retaining certain applications on-premises, the company can ensure compliance while leveraging cloud services for non-sensitive workloads.


  • Compliance with regulatory requirements
  • Control over sensitive data
  • Flexibility to leverage cloud services for non-sensitive workloads


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