Navigating Cloud Migration

Navigating Cloud Migration

Published on
Authors

With seven years in the tech industry—spanning both agile startups and global MNCs—I’ve witnessed firsthand how cloud migration transforms business operations. Whether you’re a startup sprinting to scale or a multinational optimizing legacy systems, the move to the cloud promises agility, cost-efficiency, and resilience.

But successful migration hinges on one crucial factor: choosing the right strategy for each application.

☁️ Introduction to Cloud Migration

Cloud migration refers to moving applications, infrastructure, and data from on-premises environments to platforms like AWS, Azure, or Google Cloud. It’s not just a technical upgrade—it’s a strategic initiative aligned with broader business goals.

📊 According to AWS Prescriptive Guidance, a well-executed migration reduces downtime, improves performance, and enhances scalability.

The 7Rs framework, an evolved version of Gartner’s 5Rs model, outlines seven migration strategies—each balancing speed, complexity, cost, and long-term value.

🧭 Overview of the 7Rs Framework

Strategy Description
Rehost Lift-and-shift: Move apps to the cloud with no changes.
Replatform Lift-tinker-and-shift: Make minimal optimizations during migration.
Repurchase Drop-and-shop: Replace apps with cloud-based SaaS alternatives.
Refactor Re-architect: Redesign apps to fully utilize cloud-native services.
Relocate Migrate entire environments (e.g., VMs) to the cloud without changes.
Retire Decommission outdated apps to cut costs and simplify the stack.
Retain Keep apps on-premises for now—due to compliance or strategy.

Let’s explore each strategy in detail.

🔁 Rehost (Lift and Shift)

Description: Move applications to the cloud as-is, without modifying architecture or code.

Pros:

  • Quick to implement.
  • Low risk due to minimal changes.

Cons:

  • Doesn’t take advantage of cloud-native features.
  • Potential for inefficient performance or cost.

📌 When to Use: Ideal for time-sensitive migrations or startups needing immediate scalability. At a startup, we rehosted a web app on AWS EC2 to meet sudden demand—fast, effective, and low effort.

🔧 Replatform (Lift, Tinker, and Shift)

Description: Make minor optimizations (e.g., moving a database to RDS) while migrating.

Pros:

  • Balanced trade-off between speed and optimization.
  • Reduces maintenance using managed services.

Cons:

  • Limited improvements over rehost.
  • Requires planning to avoid breaking functionality.

📌 When to Use: Great for teams aiming to cut operational overhead without full re-engineering. At an MNC, we replatformed a legacy database to RDS, improving efficiency without touching the app code.

🛒 Repurchase (Drop and Shop)

Description: Replace existing applications with SaaS alternatives like Salesforce or Google Workspace.

Pros:

  • No infrastructure or app maintenance.
  • Access to latest features and updates.

Cons:

  • Vendor lock-in.
  • Requires data migration and staff training.

📌 When to Use: Best for non-core systems with modern SaaS replacements. A team I worked with migrated from an on-prem CRM to Salesforce, improving usability and cutting IT costs.

🏗️ Refactor (Re-architect)

Description: Rebuild applications to leverage cloud-native capabilities like microservices or serverless.

Pros:

  • Maximizes performance, scalability, and agility.
  • Future-proofs infrastructure.

Cons:

  • Expensive and time-consuming.
  • Requires deep cloud expertise.

📌 When to Use: Best suited for mission-critical or high-value applications. At an MNC, we broke down a monolith into microservices using AWS Lambda and DynamoDB, unlocking incredible deployment speed and scalability.

🚚 Relocate

Description: Move entire environments (like VMware clusters) to the cloud unchanged using services like VMware Cloud on AWS.

Pros:

  • Fast, non-disruptive migration.
  • Keeps existing configurations.

Cons:

  • Doesn’t optimize cloud resources.
  • Niche applicability (e.g., for virtualized workloads).

📌 When to Use: Perfect for VM-heavy infrastructures with looming deadlines. A company facing a lease expiry relocated VMs to AWS within days.

🧹 Retire

Description: Shut down obsolete or redundant applications to reduce clutter and cost.

Pros:

  • Simplifies architecture.
  • Cuts unnecessary costs and risks.

Cons:

  • Risk of retiring something still in use.
  • Archival may be needed.

📌 When to Use: For apps with no business value. We retired outdated tools during one migration, freeing up budget and resources.

🛑 Retain

Description: Postpone migration for select applications due to compliance, complexity, or strategic reasons.

Pros:

  • Maintains control and avoids risk.
  • Gives time to plan a future move.

Cons:

  • Misses immediate cloud benefits.
  • Could create integration challenges.

📌 When to Use: Critical for apps with regulatory restrictions. A financial app handling sensitive data was retained on-prem, with a hybrid cloud roadmap in place.

💡 Real-World Scenarios: Startup vs MNC

Strategy Startup Example MNC Example
Rehost Migrated web app to AWS EC2 during a product launch Lifted legacy app to EC2 during a company merger
Replatform Shifted database to RDS to reduce admin overhead Migrated SQL DB to RDS while retaining logic on EC2
Repurchase Adopted Google Workspace to replace email servers Migrated to SAP S/4HANA ERP for standardization
Refactor Rebuilt app on AWS Lambda for elastic scaling Microservice-based redesign for global rollout
Relocate Moved a small VMware setup to AWS for fast onboarding Shifted large VMware setup to AWS due to data center closure
Retire Shut down unused side-project tools Decommissioned legacy internal applications
Retain Kept prototype app local during MVP development Retained app for regulatory compliance

🧪 Use Case: TechCorp’s Cloud Migration Journey

Let’s look at how TechCorp, a mid-sized tech firm, applied the 7Rs during its AWS migration:

Application Type Strategy Implementation Highlights
Web App (High Traffic) Refactor Migrated to AWS Lambda + DynamoDB for scalability
Internal HR System Repurchase Switched to Workday (SaaS)
Legacy Database Replatform Migrated to Amazon RDS
Dev/Test Environments Rehost Moved to AWS EC2 for flexibility and speed
Old Project Archives Retire Decommissioned and archived
Compliance-Sensitive App Retain Stayed on-prem with hybrid integration plan
Virtualized Servers Relocate Used VMware Cloud on AWS before lease expiration

✅ Result: Balanced speed, cost, and performance—aligning tech decisions with business goals.

🎯 Choosing the Right 7R Strategy

When evaluating each application, consider:

  • 📈 Business Value: High-impact apps justify refactoring.
  • 🧩 Complexity: Simple apps = Rehost; Complex = Replatform or Refactor.
  • 💸 Budget: Rehost is cheap upfront; Refactor pays off long term.
  • ⏱️ Time Constraints: Tight deadlines may require Rehost or Relocate.
  • 🧹 Technical Debt: Refactor can resolve long-standing architectural issues.

Tools like AWS Migration Hub assist in application assessment, helping teams visualize, prioritize, and strategize effectively.

⚠️ Key Challenges & Tips

From real-world experience, watch out for:

  • Data migration dependencies
  • Downtime risks
  • Cloud skills gaps
  • Change management issues

💡 Pro Tip: Don’t underestimate cross-app dependencies—especially during Rehost. Test integration points before the switch.

🌐 Multi-Cloud Notes

While the Relocate strategy typically applies within AWS ecosystems (e.g., VMware Cloud on AWS), multi-cloud strategies are becoming more popular. For example:

  • AWS for compute + Azure for analytics
  • Balances risk and leverages best-in-breed services

⚠️ Note: Multi-cloud adds orchestration complexity and should be approached with caution.

Cheers,

Sim