How to Migrate From On-premise to AWS Cloud

Cloud migration is the process of moving your organization’s digital infrastructure, applications, and data from on-premises systems to cloud-based environments. This involves transitioning from physical servers, storage devices, and networking equipment to virtual resources provided by cloud service providers.

Image source

Organizations are increasingly moving to the cloud to achieve enhanced scalability, improved efficiency, and reduced operational costs. However, many cloud migration projects fall behind schedule and exceed budget.

Cloud adoption brings several strategic advantages for organizations seeking growth, efficiency, and resilience:

• Scalability and flexibility – Operating your own compute infrastructure requires constant forecasting and adds operational overhead. Cloud platforms let businesses scale resources seamlessly up or down based on demand.
• Innovation acceleration – Cloud ecosystems such as AWS provide easy access to advanced services, including AI, machine learning, and serverless computing. This enables teams to focus on building products and innovating rather than managing infrastructure.
• Business continuity – Cloud providers handle the heavy lifting of maintaining secure, highly available infrastructure. This ensures robust disaster recovery and uptime, supporting 24/7 business operations.
• Total cost of ownership optimization – Shifting from capital-heavy hardware investments to operational expenses can change the financial equation. Although cloud isn’t always cheaper, it reduces the hidden costs of hardware, maintenance, and lost opportunities, with ongoing optimization ensuring value.
• Data residency and compliance – Regulations such as GDPR, HIPAA, ISO, and SOC increasingly shape how and where data can be stored and processed. Cloud providers offer certified, region-specific options that help organizations meet these requirements more easily.

Read more: Cloud Infrastructure Management: Components & Tools

Migrating your existing on-premises environment and systems is not easy. Let’s examine some of the common challenges organizations face when planning off-premises migration.

1. Legacy systems

Systems and hardware running on-premises often include legacy and outdated components, unsupported software versions, and difficult-to-move licences. These could pose compatibility issues with modern infrastructure hosting options, so carefully analyzing and understanding your existing footprint is crucial.

2. Skill gaps and organizational readiness

Familiarizing an existing workforce with new technologies is another common issue during a digital transformation or migration. 

AWS and other cloud providers offer powerful options, but it can be difficult to protect this arsenal of new tools from misuse. 

3. Service disruption during migration

Depending on the migration strategy, your systems may not function until you have transitioned fully to the cloud. This challenge can be mitigated, but service disruption, rollback procedures, planned migration windows, and failover processes should be thoroughly analyzed beforehand.

4. Data security and privacy concerns

Unlike traditional on-premises environments, where companies have direct control over their physical infrastructure, cloud migration introduces new security paradigms and extra effort to ensure robust data security and maintain privacy compliance throughout the transition process. 

Cloud environments often present complex configuration requirements that, if improperly set up, can lead to issues such as misconfigured access controls, weak authentication mechanisms, and temporary security gaps created during the transition.

AWS operates under a shared responsibility model where AWS secures the underlying infrastructure while customers remain responsible for securing their applications and data. 

Image source

Organizations must clearly understand this division of responsibilities, particularly regarding operating system security, network configuration, application security, and data encryption. 

5. Cost management

Managing costs effectively and avoiding budget overruns is crucial for a successful migration to the cloud. A common challenge during migration is the duplication of resources for a specific period, where organizations must simultaneously pay for both existing on-premises infrastructure and new cloud resources during the transition period. 

Fortunately, AWS offers significant migration programs, such as the AWS Migration Acceleration Program, and incentives that can offset this cost and other migration efforts needed. 

See also: AWS Cost Optimization: Strategies, Best Practices, and Tools

AWS has expanded the original Gartner “5 Rs” model to include seven comprehensive migration strategies, known as the “7 Rs”.

Image source

• Rehost (Lift and Shift): This is the fastest migration approach involving the movement of applications to AWS without any changes. It is often used as an initial step away from on-premises environments, with the goal of further optimizing the cloud environment according to cloud-native best practices later.
• Replatform (Lift, Tinker, and Shift): This migration incorporates minor optimizations to leverage cloud capabilities. Common examples include using managed services where possible, such as Amazon RDS for hosting relational databases.
• Repurchase (Drop and Shop): This involves replacing applications or tooling with cloud-native SaaS solutions when it makes financial and operational sense.
• Refactor (Re-architect): With this approach, you redesign applications to fully leverage cloud-native features, improving agility, performance, scalability, and availability.
• Relocate: Relocation involves moving on-premises infrastructure without purchasing new hardware or rewriting applications by leveraging cloud versions of platforms, such as VMWare.  You can also use this strategy to move instances or objects to a different virtual private cloud (VPC), AWS Region, or AWS account.
• Retain: Retention involves keeping applications in the existing environment due to various constraints (security, risks, dependencies, performance).
• Retire: This approach involves decommissioning or archiving applications that are no longer needed.

How to choose the right strategy?

In most cases, organizations combine strategies to fit their needs. Factors to consider include costs, business needs and expectations, application complexity, dependencies, modernization requirements, and timelines.

The AWS Migration Acceleration Program (MAP) is a comprehensive, proven, three-stage cloud migration program based on AWS’s experience migrating thousands of enterprise customers to the cloud:

Image source

Phase 1: Assess

The primary objective of the assessment phase is to build a business case and evaluate readiness. During this stage, the team will complete a comprehensive infrastructure assessment and inventory of current systems, applications, data, integration requirements, and dependencies. 

This is often performed using automated discovery tools and existing monitoring systems. The migration readiness assessment helps identify gaps along the six dimensions of the AWS Cloud Adoption Framework: business, process, people, platform, operations, and security.

After the migration readiness assessment, a business case must be developed with a clear return-on-investment projection. If the business case makes sense, and executive sponsorship and organizational buy-in are assured, the next step is a risk assessment. Potential challenges and mitigation strategies should be clearly defined, and key stakeholders should be involved early in the process.

Phase 2: Mobilize

During this phase, the organization prepares and establishes the migration foundation. A prerequisite for a robust AWS setup is the completion of a Landing Zone. This well-architected, AWS environment is scalable, secure, and can serve as a starting point for your organization to quickly launch and deploy workloads and applications with confidence.

Next, assemble a migration team with defined roles and responsibilities, choose appropriate migration tools, and establish project management processes. As a first step, plan a pilot migration and execute a small-scale migration to test methods and tools.

Phase 3: Migrate and modernize

Here, we start the actual migration execution at scale to maintain business continuity in parallel. Key activities include:

• Organizing migrations in logical groups based on dependencies
• Moving applications according to chosen strategies
• Transferring data using appropriate AWS services and tools
• Performing comprehensive testing to ensure functionality
• Executing planned production cutover with minimal downtime.

Now that we’ve seen the three migration phases, let’s take a look at the overall migration process step by step:

Step 1: Infrastructure discovery and inventory – The process begins with the comprehensive collection of data using automated discovery tools. Use tools such as the AWS Application Discovery Service on your on-premises environments to gather a complete inventory documenting detailed configuration data, performance metrics, and dependency mappings.

Step 2: Business case – Next, utilize tools like AWS Migration Evaluator to analyze your current environment and generate data-driven cost projections for AWS, thereby validating your business case for the migration.

Step 3: Migration readiness assessment – Conduct a thorough evaluation across the six dimensions of the AWS Cloud Adoption Framework — business, people, process, platform, operations, and security — to assess your readiness and any gaps you need to tackle.

Step 4: Migration task force – Secure executive leadership support, find the right people from your organization who can drive the planning and execution, and get external help from relevant partners.

Step 5: Landing zone setup – Establish your foundational AWS setup before initiating any migration activities. A landing zone setup can help you scale according to best practices. This also involves setting up base networking architectures, separating testing and production environments, and implementing baseline security controls.

Step 6: Migration planning – During this phase, define the workloads in scope and establish success metrics, such as maximum allowable downtime, and performance baselines to achieve post-cutover. 

Create dependency-driven “move groups” (workloads that must migrate together), then plan these into migration waves based on business criticality and technical complexity. Plan connectivity, identity, and data flows, and schedule the necessary outage windows and communications accordingly.

Step 7: Pre-migration setup and validation – This phase involves setting up and testing the necessary tooling and processes agreed in the planning step. This includes initialization and setup of replication settings and instances, storage configurations, and networking (e.g., testing communication over TCP ports) according to requirements.

Step 8: Pilot migration execution – Once the initial configuration is ready, select a few non-critical applications for a pilot migration to validate your processes and tools. This pilot should encompass the complete end-to-end process, including discovery, migration, testing, and cutover. Document lessons learned and refine your migration runbooks based on pilot results.

Step 9: Main migration execution – Once your pilots have been successful and you are confident in the processes, tooling, and ability to execute, you can proceed with the main migration waves according to your plan. 

Communicate the migration windows well in advance to all relevant stakeholders, along with any identified impacts or risks. Leverage your selected tooling, such as AWS Database Migration Service (DMS) and AWS Application Migration Service (MGN), to replicate data and servers, and set up necessary tooling, including CI/CD pipelines.

Step 10: Post-migration testing – After the migration is complete, perform various tests to ensure the functional and non-functional requirements are met. This can include application testing and basic functionality, database connectivity and data integrity, performance benchmarking, security validation and compliance checks, as well as integration and end-to-end testing of the systems. 

Don’t forget to also validate backup and recovery procedures in the new AWS environment.

Step 11: Migration cutover execution – Until you are 100% confident in the new environment, you will probably operate both the old and new ones for a while. 

Before you are ready to completely cutover to the new environment, confirm there is minimal lag for any live replication, you have successfully passed all the post-migration testing needed, and you have notified all stakeholders of the cutover window and expected timeline.

Ensure that rollback procedures are also documented and tested in case of issues. During the cutover window, allow the final replication cycle to complete, ensuring zero or minimal data loss. Then, update configurations such as DNS records, load balancer configurations, and firewall rules to point to the new AWS resources. 

Verify system functionality, user access, and data integrity within the first few hours after the cutover and coordinate with business users to validate application functionality.

Step 12: Post-migration optimizations – After the migration is declared successful, plan for optimizations. You can start exploring a comprehensive observability setup with tools such as Amazon CloudWatch, resource right-sizing, and auto-scaling based on actual usage patterns. 

Additionally, consider cost analysis and optimizations, including reserved instances or savings plans, as well as security audits of the migrated environment to ensure requirements are met. 

Finally, don’t neglect to update all operational documentation, runbooks, and disaster recovery procedures.

AWS offers an arsenal of migration-focused tools to make your life easier during discovery, planning, building a business case, moving data and applications, and executing migrations.

• AWS Application Discovery Service: This tool automates the process of gathering information about your on-premises data center, including server specifications, application dependencies, and workload patterns. It streamlines discovery by collecting detailed configuration, usage, and performance data, enabling you to make informed migration decisions and accurately estimate costs and resource requirements.
• AWS Application Migration Service (MGN): MGN enables organizations to perform lift-and-shift migrations (rehosting) by replicating physical, virtual, or cloud-based servers to AWS. It is designed for minimal downtime and reduced disruption, allowing for rollbacks or test migrations as needed. The service automatically converts source servers to run natively on AWS with little to no manual intervention, supporting both Windows and Linux workloads.
• AWS Database Migration Service (DMS): DMS supports seamless migration of databases to AWS with minimal downtime. It handles homogeneous migrations (e.g., Oracle to Oracle) as well as heterogeneous migrations (e.g., SQL Server to Amazon Aurora PostgreSQL). The tool constantly replicates data changes throughout the migration process, which allows you to switch over to the new database with virtually no interruption. It also provides features for schema conversion and ongoing data replication.
• AWS Migration Hub: Migration Hub provides a single, unified dashboard to track the progress of your migration projects across multiple AWS and partner tools. You can view discovered resources, create and manage migration tasks, and obtain up-to-date status reports for each application or workload. The centralized visibility helps teams coordinate, troubleshoot, and avoid duplicated effort during complex migrations.
• AWS DataSync: DataSync accelerates and automates online data transfers between on-premises storage, edge locations, and AWS storage services (e.g., S3, EFS, FSx). It offers built-in data validation, encryption in transit, and bandwidth optimization, making it especially useful for large-scale migrations or ongoing hybrid storage needs. DataSync is managed and serverless, reducing operational overhead for data movement.
• AWS Migration Evaluator: This tool helps you build a comprehensive, data-driven business case for migrating to AWS. Migration Evaluator automatically inventories your existing workloads, analyzes patterns of usage, and models future-state cost projections on AWS. It helps organizations identify the most cost-effective migration strategy, estimate the total cost of ownership (TCO), and optimize resource allocation and licensing.
• AWS Optimization and Licensing Assessment: This is used to identify opportunities to reduce license exposure (e.g., BYOL vs. license-included, right-sizing cores/editions), consolidate databases, and move to managed services where appropriate. It also helps to optimize compute, storage, and licensing before migration, especially for Microsoft workloads, Oracle, SQL Server, SAP, and other commercial software.
• AWS Transform for VMware, Mainframe, and .NET: AWS Transform is an agentic AI service that accelerates the modernization of .NET, mainframe, and VMware workloads. It uses specialized AI agents to automate assessments, code analysis, refactoring, dependency mapping, validation, and planning. With a natural language chat interface and shared workspaces, teams can collaborate in real time, track progress, and manage end-to-end delivery. 

These tools are designed to simplify and accelerate the migration journey, minimize downtime, reduce risk, and optimize costs. 

By leveraging the appropriate mix of AWS migration tools based on their specific use cases and requirements, organizations can better ensure a smooth and successful transition to the cloud. During tool selection, prioritize tools that are compatible with your existing systems and offer automation capabilities.

A successful AWS migration is driven by factors that span leadership, planning, and expertise. Addressing these fundamentals builds the foundation for a smooth transition and long-term value realization.

1. Strong executive sponsorship

Having executive commitment is non-negotiable for successful migration projects. Executive sponsorship is essential not only for securing budget and resources but also for setting clear priorities and communicating the strategic importance of the migration across the organization. 

When leadership consistently champions the migration, teams are more engaged and obstacles are resolved more decisively.

2. Comprehensive planning

Thorough upfront assessment and detailed planning mitigate risks and prevent costly missteps. This includes performing a rigorous inventory of existing assets, dependency mapping, TCO analysis, and defining clear business goals for the migration. 

Comprehensive planning enables early identification of technical gaps, compliance requirements, and potential business disruptions, allowing for mitigation before implementation begins.

3. Leveraging AWS Partners to extend your team’s skillset

Engaging an AWS Partner with Migration and Modernization Competency can be a game-changer for organizations embarking on migration journeys, especially when internal cloud expertise or capacity is limited. 

AWS Partners range from consulting firms to managed service providers and specialized migration experts that bring deep technical experience, proven methodologies, and extensive domain knowledge that complement in-house teams.

4. Iterative approach

An iterative, phased approach will be more successful than a “big bang” migration. 

Incrementally moving workloads while prioritizing based on business criticality and complexity reduces operational risk and provides valuable feedback after each stage. Each phase serves as a learning opportunity, informing subsequent waves and allowing teams to refine their processes and tools.

5. Connection with your AWS Account Team

Establishing and nurturing a strategic partnership with AWS and its ecosystem of partners is a key advantage. AWS account teams, solution architects, and managed service providers can offer expert guidance, best practices, and technical support throughout the migration journey. 

Regular communication and collaboration help organizations stay aligned on strategic goals and rapidly address emerging challenges.

6. Innovation pipeline

Migration to AWS is not the end state, but rather the foundation for ongoing innovation. Organizations that excel continually assess AWS’s evolving portfolio, including IoT, machine learning, analytics, and other emerging services to find new opportunities to deliver business value.

Establishing a structured innovation pipeline ensures your cloud environment remains a source of competitive advantage, not just a cost center.

Spacelift takes cloud automation and orchestration to the next level. It is a platform designed to manage infrastructure-as-code tools such as OpenTofu, Terraform, CloudFormation, Kubernetes, Pulumi, Ansible, and Terragrunt, allowing teams to use their favorite tools without compromising functionality or efficiency.

Spacelift provides a unified interface for deploying, managing, and controlling cloud resources across various providers. Still, it is API-first, so whatever you can do in the interface, you could do via the API, the CLI it offers, or even the OpenTofu/Terraform provider.

The platform enhances collaboration among DevOps teams, streamlines workflow management, and enforces governance across all infrastructure deployments. Spacelift’s dashboard provides visibility into the state of your infrastructure, enabling real-time monitoring and decision-making, and it can also detect and remediate drift.

You can leverage your favorite VCS (GitHub/GitLab/Bitbucket/Azure DevOps), and executing multi-IaC workflows is a question of simply implementing dependencies and sharing outputs between your configurations.

With Spacelift, you get:

• Policies to control what kind of resources engineers can create, what parameters they can have, how many approvals you need for a run, what kind of task you execute, what happens when a pull request is open, and where to send your notifications
• Stack dependencies to build multi-infrastructure automation workflows with dependencies, having the ability to build a workflow that, for example, generates your EC2 instances using Terraform and combines it with Ansible to configure them
• Self-service infrastructure via Blueprints, enabling your developers to do what matters – developing application code while not sacrificing control
• Creature comforts such as contexts (reusable containers for your environment variables, files, and hooks), and the ability to run arbitrary code
• Drift detection and optional remediation

If you want to learn more about Spacelift, create a free account today or book a demo with one of our engineers.

Migrating from on‑premises infrastructure to AWS is a transformative endeavour that touches technology, teams, and ways of working. This blog surfaced the most common challenges, offered practical guidance for successful adoption, and highlighted best practices proven in real-world implementations. 

Plan your strategy, and anchor every decision to a measurable business outcome. Leverage proven frameworks, strong governance, and best practices to substantially increase the likelihood of success. Invest in planning and embrace automation. A migration to the cloud is not a finish line; it’s the start of ongoing optimization, modernization, and value realization.