Migrating Workloads from AWS to Azure: A Structured Approach for Cloud Architects

Organizations migrating workloads from Amazon Web Services (AWS) to Microsoft Azure face significant technical and operational challenges. Based on proven migration patterns, this structured approach provides cloud architects with a complete lifecycle framework emphasizing risk mitigation through architectural consistency.

Core Migration Principle: Like-for-Like Architecture

The foundation of successful migration is maintaining identical architecture during transition. Replicate existing AWS configurations on Azure using equivalent services, preserving operational patterns and performance characteristics. While this postpones modernization, it strategically manages risk by avoiding scope creep and maintaining operational confidence. Optimization occurs only after stable operation on Azure.

The Five-Phase Migration Lifecycle

Phase 1: Plan
Critical decisions made here determine migration success. Beyond automated discovery tools, engage subject matter experts to identify undocumented dependencies like scheduled scripts and authentication flows. Deliverables include:

• Complete dependency-mapped architecture documentation
• Performance baselines (throughput, latency, error rates)
• Rollback trigger criteria

Service mapping examples:

• AWS RDS → Azure SQL Database
• AWS Lambda → Azure Functions
• Amazon S3 → Azure Blob Storage

Select migration strategy using this comparison:

Strategy	Downtime	Risk Level	Rollback Capability
Big Bang	High	High	Difficult
Phased	Low	Medium	Moderate
Blue/Green	Low	Low	Easy

Blue/green deployment (running both environments simultaneously) is recommended despite temporary cost duplication due to superior risk reduction.

Phase 2: Prepare
Convert planning into executable assets:

• Infrastructure deployment: Implement Infrastructure as Code (IaC) using Bicep, Terraform, or ARM templates
• CI/CD pipeline updates: Enable dual deployment to AWS and Azure
• Code refactoring: Replace AWS SDKs with Azure equivalents (e.g., CloudWatch → Application Insights)
• Chaos engineering: Test failure scenarios with Azure Chaos Studio
• Operations readiness: Replicate monitoring with Azure Monitor dashboards

Phase 3: Execute
The highest-risk phase requiring meticulous execution:

• Follow migration runbooks with validation checkpoints
• Maintain real-time health dashboard using Azure Monitor
• Preserve AWS environment for rollback during validation window
• Conduct post-cutover regression testing before declaring success

Phase 4: Evaluate
Validation beyond basic functionality:

• Performance comparison against AWS baselines
• AWS CloudTrail verification confirming no residual traffic
• Data consistency confirmation after stopping replication
• Operational validation of backup/restore and incident procedures
• Formal sign-off against predefined success criteria
• Post-mortem documentation of lessons learned

Phase 5: Decommission
Often overlooked critical final steps:

• Final AWS backups and snapshots
• Resource inventory via AWS Config
• Identification of orphaned resources
• New Azure performance baseline establishment
• Azure Well-Architected Framework review

Execution Ownership Strategy

Avoid outsourcing the entire migration. While partners like Microsoft Industry Solutions can lead planning and automation development, the workload team must execute production cutover. This ensures:

• Early discovery of workload-specific issues
• Knowledge transfer to operational teams
• Maintained ownership and accountability

Realistic Expectations

Successful migrations require:

• Concrete plans with measurable objectives
• Stakeholder alignment across teams
• Phased validation checkpoints
• Tolerance for unexpected challenges

Conclusion

Migrating from AWS to Azure demands strategic discipline. The like-for-like approach with blue/green deployment provides the safety net needed for enterprise transitions. Post-migration, leverage Azure's native tooling for optimization before tackling technical debt reduction.

Further Reading:
Complete migration guide series: Migrate workloads from AWS to Azure

Share your migration experiences below:

• Which strategies proved most effective?
• What unexpected challenges emerged during validation?
• How did team structure impact outcomes?