Design a Cloud Migration Strategy

To migrate a monolithic on-premise application to a cloud-native architecture, I propose a four-phase strategy aligned with Microsoft's Cloud Adoption Framework. First, the Assessment phase involves inventorying dependencies and defining success metrics. Second, in the Planning phase, we select the right pattern based on specific workloads. For legacy components where downtime is unacceptable, I recommend a 'Lift-and-Shift' to Azure VMs immediately. However, for stateless web tiers, a 'Re-platform' to Azure App Service offers better cost efficiency without full refactoring. Finally, the core database should be targeted for 'Refactoring' into microservices using Azure SQL or Cosmos DB to achieve true scalability. Third, execute the migration in waves, starting with non-critical services to validate our CI/CD pipelines using Azure DevOps. We must implement robust blue-green deployment strategies to ensure zero-downtime transitions. The fourth phase focuses on Optimization, enabling auto-scaling and integrating Azure Monitor for real-time observability. This approach balances immediate business needs with long-term architectural agility, ensuring we leverage cloud elasticity while maintaining system stability throughout the transition.