Cloud migration is the process of moving digital assets — applications, data, workloads, and IT resources — from on-premises infrastructure to cloud-based environments, or between cloud providers. It's a fundamental transformation enabling scalability, agility, and cost optimization across AWS, Azure, GCP, and other platforms. Migration isn't a one-time lift; it requires strategic planning through assessment, execution, and continuous optimization phases. Understanding the 7 R's framework (Rehost, Relocate, Replatform, Refactor, Repurchase, Retire, Retain) is essential, with Azure's Cloud Adoption Framework extending this to 8 R's by splitting Refactor into Refactor, Rearchitect, and Rebuild — each application demands a tailored strategy based on business goals, technical complexity, and ROI timelines.
What This Cheat Sheet Covers
This topic spans 21 focused tables and 138 indexed concepts, 129 flashcards. Below is a complete table-by-table outline of this topic, spanning foundational concepts through advanced details.
A jump-to index of every table row in this cheat sheet.
An interactive map of every table and concept in this topic.
Table 1: Migration Strategies (The 7+ R's)
Every application you move needs one of these decisions made about it, and the choice drives everything downstream — cost, timeline, and how much cloud value you actually capture. They range from the fast-but-shallow Rehost (lift-and-shift, no code changes) all the way to a full Rebuild from scratch, with Retire and Retain reminding you that not everything should move at all. Pick based on business value and technical debt, not habit.
| Strategy | Example | Description | |
|---|---|---|---|
Move VM from vSphere to AWS EC2 with no code changes | • Fastest migration approach — relocate applications as-is to cloud infrastructure • minimal disruption but limited cloud-native benefits. | ||
Migrate SQL Server to Azure SQL Database with minor optimizations | Partial modernization — make small adjustments (e.g., switching to managed databases) to gain cloud benefits without full rearchitecture. | ||
Break monolith into microservices on Kubernetes | • Complete redesign for cloud-native architecture • highest effort but maximizes scalability, resilience, and cost efficiency. | ||
Replace Exchange Server with Office 365 SaaS | • Move to commercial SaaS product • eliminates infrastructure maintenance but may require process changes. | ||
Decommission unused CRM system saving 30% infrastructure costs | • Eliminate obsolete applications identified during portfolio assessment • reduces technical debt and operational overhead. | ||
Keep mainframe on-premises due to compliance constraints | • Delay migration for apps with dependencies, compliance issues, or business reasons • revisit in future migration waves. Use Azure Arc for unified management. | ||
Use AWS Application Migration Service for hypervisor-level transfer | • AWS-specific strategy — move entire VMware workloads to VMware Cloud on AWS with minimal changes • rapid datacenter exit. | ||
Reimagine legacy DHCP server as Azure PaaS service from scratch | • Full redevelopment using cloud-native services when legacy systems are too outdated to modernize • Azure CAF 8th R; highest effort but eliminates legacy constraints entirely. |