Feeling overwhelmed by the options when moving to the cloud? You’re not alone. Deciding between rehosting and replatforming can shape your project’s success, affecting cost, speed, and future flexibility.
Understanding the key differences is crucial before you take the plunge. This article breaks down what each approach means, highlights when to choose one over the other, and offers practical tips to help you make the smartest move for your organization. Let’s clear up the confusion together.
Rehost vs Replatform: Choosing the Right Cloud Migration Approach
When moving your applications and workloads to the cloud, there are several strategies available. Two of the most common approaches are “rehosting” and “replatforming.” If you’re wondering how rehosting compares to replatforming—and which one best fits your organization’s needs—you’re in the right place. Let’s break down the key differences, advantages, challenges, and factors to consider when making this fundamental cloud migration decision.
What Is Rehosting?
Rehosting, often called “lift and shift,” is like moving your belongings from one house to another without rearranging or upgrading anything. The application or workload is moved from its current environment (usually on-premises) to the cloud with little or no modification.
Key Characteristics of Rehosting:
- Minimal changes to the application code or architecture.
- Speed-focused: typically the fastest migration path.
- Reduces risk by maintaining the current application structure.
- Often chosen as a first step toward modernization.
Typical Rehosting Steps
- Assess current infrastructure and applications.
- Select your target cloud platform and map resources.
- Move applications and databases as they are to the cloud.
- Reconfigure network and security settings for the cloud environment.
- Test and validate performance after migration.
What Is Replatforming?
Replatforming is sometimes called “lift, tinker, and shift.” It involves migrating applications to the cloud but making some optimizations or adjustments to benefit from cloud-native capabilities—without changing the core application architecture.
Key Characteristics of Replatforming:
- Selective changes to take advantage of cloud features (like managed databases or auto-scaling).
- Usually requires minor code or configuration adjustments.
- Balances speed and modernization, improving cost or performance vs. a straight rehost.
- Often the middle ground between a simple lift-and-shift and a full refactor.
Typical Replatforming Steps
- Evaluate target cloud platform features.
- Identify potential cloud optimizations (e.g., switching to managed services).
- Adjust application (minor code or configuration changes) for compatibility.
- Migrate application to the cloud environment.
- Test thoroughly to ensure both functionality and improved performance.
Key Differences: Rehost vs Replatform
| Aspect | Rehost | Replatform |
|---|---|---|
| Application Changes | None or minimal | Minor, targeted adjustments |
| Speed of Migration | Fastest option | Moderate—slower than rehost, faster than refactor |
| Complexity | Low | Medium |
| Cloud Optimization | Limited | Moderate |
| Cost (Initial) | Usually lowest upfront | Slightly higher |
| Cloud Benefits Accessed | Basic (primarily infrastructure-as-a-service) | Some cloud-native features |
| Skills Required | General IT/cloud | App development and cloud expertise |
Benefits of Rehosting
Moving fast is sometimes key. Here’s why organizations often choose to rehost:
- Speed to cloud: Rehosting allows you to migrate quickly, which is ideal if you have a tight deadline or data center contract expiration.
- Lower migration risk: Little to no code changes mean fewer chances to break things.
- Cost savings: Potential to reduce operational costs by moving from expensive on-prem infrastructure.
- Eases future modernization: Once in the cloud, it’s easier to gradually update or modernize applications.
Challenges of Rehosting
Despite its appeal, rehosting isn’t perfect for everyone:
- Missed cloud potential: Because applications aren’t optimized, you might not benefit from auto-scaling, cost efficiencies, or improved resilience.
- Technical debt: Legacy issues and inefficiencies are carried into the cloud.
- Limited ROI: Cost savings can be modest when compared to deeper modernization strategies.
Benefits of Replatforming
Replatforming is for teams that want more than just a move:
- Better use of cloud services: Take advantage of managed databases, caching, monitoring, and more.
- Improved performance and cost: Tweaks can enable savings through auto-scaling or resource right-sizing.
- Reduced operational burden: Managed services mean less infrastructure maintenance.
- Competitive edge: Initial optimizations can keep you ahead of slow-moving competitors.
Challenges of Replatforming
It’s not all upside—a few hurdles to keep in mind:
- More complexity: Changes, even minor ones, require testing and reskilling.
- Increased migration time: More tasks mean longer timelines compared to rehosting.
- Potential for unintended issues: Adjustments may affect application stability or require more extensive testing.
How to Choose: Rehost or Replatform?
Selecting between rehosting and replatforming comes down to your priorities. Consider these practical steps to align your choice with your business goals:
1. Assess Your Application Portfolio
- Which applications are cloud-ready?
- Identify mission-critical apps, legacy constraints, and licensing dependencies.
2. Define Business Objectives
- Is speed your priority? (Rehosting)
- Do you need to reduce operational costs and tap into new features? (Replatforming)
- How much downtime is acceptable?
3. Evaluate Resources & Skills
- Do you have cloud and application development skills in-house?
- Are you prepared to support and manage post-migration?
4. Map Out Migration Phases
- Start with less critical workloads to build experience.
- Consider piloting both approaches to compare results.
5. Estimate Costs
- Include direct migration expenses, required cloud services, and ongoing management.
- Replatforming may cost more upfront but unlocks bigger savings or efficiencies over time.
Cost Considerations and Tips
Cloud migration is as much a financial decision as a technical one. Here’s what to keep in mind:
- Rehosting is generally the least expensive up front, as you’re avoiding redevelopment expenses. However, operational costs may not decrease much if you continue running as before in the cloud.
- Replatforming can involve additional costs for development, integration, and validation. However, these upgrades can quickly pay off if they improve efficiency or allow you to use better resources.
- Analyze your cloud provider’s pricing models—using managed or auto-scaled services can lead to ongoing savings that more than offset migration costs.
- Factor in long-term operational and maintenance costs, not just initial migration.
- Seek cloud-native discount options, like reserved instances, which can reduce run costs for either migration type.
Best Practices for a Smooth Migration
Whichever approach you choose, a few key best practices can help you succeed:
- Perform a detailed assessment of all applications and dependencies before migrating.
- Create a migration plan that includes clear goals, timelines, milestones, and rollback strategies.
- Test thoroughly in a staging environment before going live.
- Prepare your team—invest in training and documentation for post-migration support.
- Monitor and optimize after migration—continually tune resources to improve performance and reduce costs.
- Consider a hybrid approach—some applications may be best rehosted while others are replatformed, depending on your portfolio.
Real-World Scenarios
When Rehosting Makes Sense
- Large enterprises facing data center shutdowns and tight timelines.
- Organizations with limited developer resources, needing a quick migration.
- Workloads with complex legacy code that aren’t ready for refactoring.
When Replatforming Is Better
- Apps that would benefit from database-as-a-service, improved monitoring, or managed backup.
- Businesses with some flexibility in timeline wanting better cloud efficiency.
- Teams looking to reduce manual infrastructure management.
A Brief Word on Other Migration Strategies
While rehost and replatform are popular, they’re part of a broader set of cloud migration options:
- Refactor: Rewrite and deeply modernize applications for cloud-native architecture.
- Replace: Swap custom apps for commercial SaaS solutions.
- Retire and Retain: Decommission or leave some apps on-premises.
- Rearchitect: Completely rebuild using new cloud paradigms.
Consider rehost and replatform as pragmatic stepping stones, especially if you’re early in your cloud journey.
Conclusion
In summary, rehosting and replatforming are two tried-and-true approaches for getting applications into the cloud. Rehosting is your quickest, lowest-risk path; perfect for tight deadlines and limited resources. Replatforming, while requiring a bit more effort, unlocks some of the true benefits of cloud such as managed services, auto-scaling, and improved cost efficiency.
There’s no one-size-fits-all answer—the right choice depends on your business goals, current application landscape, and available expertise. With careful planning, thoughtful assessment, and an openness to hybrid approaches, your journey to the cloud can be both smooth and rewarding.
Frequently Asked Questions (FAQs)
What is the main difference between rehosting and replatforming?
Rehosting moves applications to the cloud with minimal or no changes (lift and shift), while replatforming involves minor tweaks to take advantage of some cloud features without changing the core application architecture.
Is rehosting always cheaper than replatforming?
Rehosting usually requires less upfront investment because it avoids modifying applications. However, replatforming, while more costly initially, may lead to better long-term savings through optimized resource use and managed services.
Can I start by rehosting and then replatform later?
Yes! Many organizations initially rehost for speed and simplicity, then gradually replatform or refactor as resources and priorities allow, unlocking more cloud benefits over time.
Which migration strategy is less risky?
Rehosting is generally less risky, as it involves fewer changes. The fewer changes you make during migration, the less likely you are to introduce new issues. However, replatforming can be low-risk if handled with careful testing and planning.
Do I need a cloud expert to replatform?
While some replatforming tasks (like moving to a managed database or enabling auto-scaling) are straightforward, deeper optimization requires expertise in both your app and your cloud provider. Investing in upskilling or working with experienced partners can make the process much smoother.