Understanding Cloud Migration
Cloud migration is the process of relocating applications, data, and IT workloads from on-premises infrastructure, or from one cloud provider to another, into a target cloud environment such as AWS, Microsoft Azure, or Google Cloud Platform. It covers everything from moving a single virtual machine to re-platforming an entire enterprise data center, and it is usually driven by a specific business trigger: a data center lease expiring, aging hardware needing replacement, a merger requiring infrastructure consolidation, or a push for elasticity that on-prem capacity cannot provide.
The 6 R’s Framework
AWS popularized a framework, often extended to 7 R’s, for categorizing how each application should move:
- Rehost – lift and shift a workload as-is onto cloud infrastructure with minimal changes.
- Replatform – make small optimizations during the move, such as swapping a self-managed database for Amazon RDS, without changing the core architecture.
- Refactor/re-architect – redesign the application to be cloud-native, for example decomposing a monolith into microservices or serverless functions.
- Repurchase – replace the application with a SaaS equivalent, such as moving from a self-hosted CRM to Salesforce.
- Retire – decommission applications that are no longer needed.
- Retain – keep certain workloads on-premises, often due to compliance, latency, or dependency constraints.
How Migration Projects Are Executed
A typical migration follows a discovery and assessment phase, using tools like AWS Application Discovery Service or Azure Migrate to inventory servers, map application dependencies, and estimate right-sized target infrastructure. Teams then build a migration plan organized into waves, grouping applications by complexity, risk, and business priority, an approach often called a “migration factory.” Execution relies on tooling such as AWS Application Migration Service (MGN), Azure Site Recovery, or database-specific tools like AWS Database Migration Service to replicate data with minimal downtime. After cutover, teams validate functionality and performance before decommissioning the source environment.
Example Scenario
A mid-size insurance company running a monolithic .NET application on VMware needs to exit its data center lease within 12 months. It uses Azure Migrate to assess VM sizing and dependencies, replicates the VMs to Azure using Azure Site Recovery, tests the replicated environment in an isolated network, and performs a cutover during a scheduled maintenance window with a rollback plan in place. Post-migration, the team right-sizes VM SKUs and evaluates which components could later be replatformed onto Azure SQL Database.
Why Teams Migrate
Common drivers include eliminating data center capital expenditure, gaining elastic capacity for variable workloads, improving disaster recovery posture using multi-region cloud services, accessing managed services that reduce operational burden, and supporting geographically distributed users through a global provider network.
Trade-offs and Risks
Migrations carry real risk: cutover windows can cause downtime, dual-running costs accumulate while both environments operate in parallel, teams often underestimate the effort required to remediate hard-coded IP addresses, legacy authentication, or unsupported OS versions, and a rushed lift-and-shift can simply relocate technical debt into a more expensive environment if no further optimization follows.
Best Practices
- Run a thorough discovery and dependency-mapping phase before committing to a migration strategy per application.
- Sequence migration waves starting with low-risk, high-learning workloads to build team confidence and tooling maturity.
- Establish the target landing zone and governance guardrails before migrating any production workload.
- Involve FinOps early to model target-state costs and avoid post-migration bill shock.
- Treat migration as phase one of a longer modernization journey rather than a final destination.
Frequently Asked Questions
What is Cloud Migration?
Cloud migration is the process of moving applications, data, and infrastructure from on-premises data centers (or another cloud) into a public cloud platform such as AWS, Azure, or GCP.
How does Cloud Migration work?
Cloud Migration works by combining the components described in the sections above. The main page walks through the architecture, the typical use cases, and the trade-offs to weigh before adopting it.
Why does Cloud Migration matter?
Teams adopt Cloud Migration to ship faster, run more reliably, and reduce the cognitive load on engineers. The benefits, limits, and adjacent tools are covered in the body above.
When should you use Cloud Migration?
Use Cloud Migration when the problems it solves match what your team is hitting today. The page above outlines the signals that mean you should adopt it now, and the cases where a simpler approach is fine.
