On-Prem to Cloud: Migration Approaches

Introduction☁️

Migrating applications from on-premises data centers to the cloud is one of the most significant steps an organization can take toward digital transformation. Whether you aim to cut infrastructure costs, modernize outdated systems, improve scalability, or accelerate innovation, the cloud provides an unparalleled platform for growth.

However, application migration is not simply about moving workloads from one location to another—it’s about choosing the right strategy for each application based on its business value, technical readiness, and future requirements. That’s where the “6 R’s” framework comes in, offering a set of tried-and-tested approaches to guide your migration journey.

🚀 Why Move to the Cloud?

Organizations are shifting to the cloud for a va

riety of reasons:

• 🌐 Global reach – Deploy applications in multiple regions to serve customers worldwide.

• 💰 Cost optimization – Reduce capital expenditures and pay only for the resources you use.

• ⚡ Agility – Provision infrastructure in minutes instead of weeks.

• 🔒 Security & compliance – Meet strict industry standards with advanced security tools.

• 🔧 Innovation – Access cutting-edge services like AI, IoT, analytics, and serverless computing.

🛠 The 6 R’s of Cloud Migration

The 6 R’s framework outlines six core strategies for moving applications from on-premises environments to the cloud.

Rehosting, also known as “lift and shift,” involves moving applications as they are—without altering the code—into cloud infrastructure such as virtual machines. It’s the fastest way to migrate with minimal disruption, though it may not take advantage of cloud-native features.

Replatforming makes small but meaningful adjustments during migration, such as upgrading an application version, migrating databases to managed services, or hosting on a managed runtime. This approach balances effort and reward, unlocking some operational benefits without a full rebuild.

Repurchasing replaces an existing application entirely with a Software-as-a-Service (SaaS) product—think CRM, ERP, or HR systems. This approach removes the need for application management and infrastructure upkeep, though it may require adapting business processes to fit the SaaS model.

Refactoring or re-architecting is a deeper transformation, redesigning applications to be fully cloud-native. This often involves adopting microservices, containers, or serverless architectures. While the most resource-intensive, it offers the highest scalability, flexibility, and long-term cost optimization.

Retiring means decommissioning applications that are outdated or no longer provide value. This simplifies the IT environment, reduces costs, and frees resources for higher-priority workloads.

Retaining certain applications on-premises may be necessary for compliance, security, or latency reasons. Many organizations adopt a hybrid model, keeping some workloads in their data centers while integrating with the cloud for others.

📊 Migration Approach Comparison

🧭 A Step-by-Step Guide to Cloud Migration

Successfully migrating to the cloud requires a phased approach that balances planning with execution.

Phase 1: Assessment and Planning

1. Application Portfolio Analysis: Identify all applications, their dependencies, business criticality, and technical complexity. Decide which of the 6 R's applies to each one.

2. Define Objectives and KPIs: Set clear goals for the migration (e.g., cost reduction, better security) and establish metrics to track success.

3. Cloud Provider Selection: Choose a cloud provider like AWS, Azure, or GCP based on your technical and business needs, services offered, and cost.

4. Develop a Migration Strategy: Create a detailed plan with timelines and resources. Prioritize applications based on their business value and migration difficulty.

5. Security and Compliance Planning: Plan your cloud security posture from the start to ensure compliance with relevant regulations.

Phase 2: Execution

1. Pilot Migration: Start with a non-critical application to test your migration processes and identify potential issues. Use the chosen migration approach (e.g., Rehost a simple web server).

2. Implement Migration Waves: Group applications into waves and migrate them systematically.

   • Rehost Example: Lift and shift virtual machines (VMs) running your application to cloud-based VMs (e.g., EC2 in AWS, Azure VMs).

   • Replatform Example: Migrate your on-premises database to a managed cloud database service (e.g., RDS in AWS, Azure SQL Database). Update your application configuration to connect to the new database.

   • Repurchase Example: Migrate users and data from your on-premises CRM system to a cloud-based CRM like Salesforce or Dynamics 365.

   • Refactor/Re-architect Example: Break down a monolithic application into microservices and deploy them using containerization (e.g., Docker, Kubernetes) on a cloud platform.

3. Data Migration: Plan a robust data migration strategy to ensure data integrity and minimal downtime. Choose appropriate tools and techniques for data transfer.

4. Testing and Validation: Thoroughly test migrated applications in the cloud environment to ensure functionality, performance, and security.

Phase 3: Optimization and Management

1. Performance Monitoring: Implement monitoring tools to track the performance and health of your cloud-based applications.

2. Cost Optimization: Continuously analyze your cloud usage and identify opportunities to optimize costs (e.g., rightsizing instances, utilizing reserved instances, leveraging serverless services).

3. Security Hardening: Implement cloud-native security best practices and tools to protect your applications and data.

4. Automation: Automate infrastructure provisioning, deployment, and management tasks to improve efficiency and reduce errors.

Conclusion

Cloud migration is a journey that requires careful planning and the right strategy. By understanding the different approaches and following a structured guide, you can successfully transition your organization to the cloud, driving innovation, agility, and cost efficiency.