AWS Migration Guide: On-Premises, VMware, and VM Migration to AWS

Why Organizations Migrate to AWS

Before diving into the technical process, it helps to understand what actually drives migration decisions, since this context shapes which migration strategy makes sense for your specific situation. Common drivers include reducing data center overhead and hardware refresh costs, gaining elastic scalability that on-premises infrastructure cannot easily match, improving disaster recovery capabilities, and positioning the organization to adopt cloud native services like managed databases and serverless computing that are simply not available on traditional infrastructure.

Understanding your own primary driver matters because it directly influences whether a quick, minimal change migration or a deeper, more transformative approach makes more sense for your organization.

The AWS Migration Strategies: Understanding the 7 Rs

AWS organizes migration approaches into seven common strategies, often called the 7 Rs, and choosing the right one for each workload is the single most important early decision in any migration project.

Rehost (Lift and Shift)

This involves moving applications to AWS with minimal or no changes to the underlying architecture. It is the fastest approach and works well for a large scale, time sensitive on-premises to AWS cloud migration, particularly when you need to exit a data center quickly or meet a hard deadline like a lease expiration.

Replatform (Lift, Tinker, and Shift)

This involves making a few targeted optimizations during migration without fully re-architecting the application, such as moving a self managed database to Amazon RDS while keeping the application logic largely unchanged. It offers meaningful benefits over rehosting without the full time investment of a complete re-architecture.

Repurchase

This involves moving to a different product entirely, often replacing a self managed or on-premises application with a SaaS alternative. This strategy sits somewhat outside pure infrastructure migration but often gets evaluated alongside it during broader modernization planning.

Refactor or Re-architect

This involves substantially redesigning an application to take full advantage of cloud native features, such as breaking a monolithic application into microservices or adopting serverless components. It requires the most investment but delivers the greatest long term benefits in scalability and operational efficiency.

Relocate

This strategy specifically applies to VMware environments, moving VMware based applications to AWS without purchasing new hardware, rewriting applications, or modifying existing operations. It is worth understanding in detail given how common VMware environments remain in enterprise infrastructure.

Retain

Some workloads are not ready or suitable for migration yet, whether due to compliance requirements, recent infrastructure investment, or application dependencies that need further untangling first. Retaining these workloads temporarily, while migrating everything else, is a legitimate and often necessary part of a realistic migration plan.

Retire

Migration planning frequently uncovers applications that are no longer needed at all. Retiring these systems entirely, rather than migrating them, reduces both migration scope and ongoing operational costs.

VMware to AWS Migration: VMware Cloud on AWS

For organizations running significant VMware infrastructure, VMware Cloud on AWS deserves particular attention as a migration path, since it directly addresses the "relocate" strategy mentioned above.

What VMware Cloud on AWS Actually Offers

This service runs the VMware SDDC stack, including vSphere, vSAN, and NSX, directly on dedicated AWS infrastructure. This means you can migrate VMware based virtual machines to AWS without converting them to a different hypervisor format, without rewriting applications, and largely without retraining your operations team on entirely new tools and workflows.

Why This Matters for VM Migration in Cloud Computing

Converting virtual machines between hypervisor formats, such as from VMware to a native AWS EC2 based environment, introduces genuine technical risk and testing overhead. VMware Cloud on AWS sidesteps much of that complexity by preserving your existing VMware operational model while gaining AWS's underlying infrastructure, elastic capacity, and proximity to native AWS services for workloads that do eventually need deeper integration.

When VMware Cloud on AWS Makes Sense

This approach fits organizations wanting a faster path off aging on-premises hardware without a full re-architecture project, those with substantial existing VMware operational expertise they want to preserve, and those planning a phased, longer term migration where some workloads eventually move to native AWS services while others remain on the VMware stack indefinitely.

AWS Application Migration Service for VM Migration

For organizations pursuing a more traditional rehost strategy, AWS Application Migration Service, commonly called MGN, is the primary tool AWS provides for migrating physical, virtual, and cloud based servers to AWS.

How AWS Application Migration Service Works

The service uses continuous, block level replication from your source servers to AWS, meaning your source environment keeps running normally throughout the migration process rather than requiring extended downtime for a single large data transfer. Once replication is established and tested, cutover to AWS happens in minutes, since the target instances are already synchronized and ready.

Key Advantages for On-Premises to AWS Migration

This approach minimizes downtime significantly compared to older migration methods that required extended maintenance windows. It also supports automated conversion of your servers into fully functional, AWS native instances, meaning you are not simply running a VMware environment nested inside AWS, but genuinely native EC2 instances that can take full advantage of AWS services from day one.

On-Premises to AWS Migration Step by Step

Here is a practical, sequenced approach reflecting how successful migrations are typically structured.

Step 1: Assess Your Current Environment

Before moving anything, build a complete inventory of your existing infrastructure, including servers, applications, dependencies, and data volumes. Tools like AWS Application Discovery Service can automate significant portions of this assessment, mapping application dependencies you might not have fully documented internally.

Step 2: Choose Your Migration Strategy Per Workload

Not every application needs the same approach. Categorize your workloads according to the 7 Rs framework, recognizing that a single migration project often uses several different strategies simultaneously depending on each application's specific requirements and constraints.

Step 3: Design Your Target AWS Architecture

Plan your VPC structure, subnet design, security groups, and IAM policies before migration begins, rather than improvising this during the migration itself. A well planned network architecture prevents significant rework later and establishes proper security boundaries from the outset.

Step 4: Set Up Migration Tooling

Depending on your chosen strategy, this might mean deploying AWS Application Migration Service agents on source servers, setting up VMware Cloud on AWS if pursuing a relocate strategy, or configuring AWS Database Migration Service if you are separately migrating databases alongside application servers.

Step 5: Begin Replication and Testing

Start continuous replication to AWS while your source environment remains fully operational. Use this period to conduct non-disruptive test launches of your migrated instances in an isolated AWS environment, validating that applications function correctly before committing to a full cutover.

Step 6: Execute Cutover

Once testing confirms readiness, schedule your cutover window. With continuous replication based approaches, this window is typically measured in minutes rather than hours, since the target environment is already synchronized and simply needs a final incremental sync before traffic switches over.

Step 7: Optimize Post-Migration

Migration completion is not the finish line. Review your newly migrated instances for right sizing opportunities, evaluate whether specific workloads are now good candidates for further replatforming or refactoring, and implement cost optimization practices like Reserved Instances or Savings Plans once usage patterns stabilize.

Common Challenges in On-Premises to Cloud Migration AWS Projects

A few recurring issues show up across many migration projects, regardless of organization size.

Underestimating Dependency Mapping

Applications rarely exist in isolation, and missing a dependency, such as an internal API another application relies on, can cause unexpected failures during cutover. Thorough dependency discovery before migration begins prevents most of these surprises.

Network Latency and Bandwidth Constraints

Large scale data replication requires adequate bandwidth between your source environment and AWS. For very large data volumes, AWS offers physical data transfer options like AWS Snowball as an alternative to relying entirely on network based replication.

Licensing Considerations

Software licensing models built around on-premises assumptions do not always translate cleanly to cloud environments. Review licensing terms for critical software before migration, since some vendors have specific cloud licensing programs or restrictions worth understanding in advance.

Security and Compliance Gaps

Migrating infrastructure without revisiting security architecture can inadvertently carry forward, or even worsen, existing security gaps. Use migration as an opportunity to implement stronger IAM practices, encryption standards, and network segmentation rather than simply replicating existing on-premises security configurations as is.

Choosing Between Rehost and Relocate for VMware Environments

If you are specifically working through a VMware to AWS migration decision, the choice between AWS Application Migration Service, which converts to native EC2 instances, and VMware Cloud on AWS, which preserves your VMware stack, deserves careful consideration.

Choose native EC2 migration through Application Migration Service if your long term goal is deeper integration with AWS native services and you are comfortable with your operations team adapting to AWS specific tooling. Choose VMware Cloud on AWS if preserving operational continuity and existing VMware expertise matters more in the near term, or if you plan a longer, phased transition rather than an immediate full migration to native AWS services.

Conclusion

A successful AWS migration guide ultimately comes down to matching the right strategy to each specific workload rather than applying a single approach uniformly across your entire environment. Whether you are pursuing a straightforward rehost using AWS Application Migration Service, preserving your VMware environment through VMware Cloud on AWS, or planning a longer term refactoring effort for select applications, thorough assessment and dependency mapping before migration begins prevents the majority of problems that derail these projects. Approach migration as a structured, phased process rather than a single event, and use the post-migration period to genuinely optimize your new AWS environment rather than simply replicating your old infrastructure's configuration in a new location.