.png)
📘 Chapter 8:
- Anand Nerurkar
- Apr 12
- 3 min read
Cloud Migration Strategy (6R + Migration Factory)
1. The Reality of Cloud Migration in BFSI
Most banks started cloud journeys with ambition:
“Move everything to cloud”
“Modernize quickly”
“Reduce cost”
❗ What Actually Happened
Lift-and-shift without optimization
Broken integrations
Security & compliance concerns
Cost overruns
Cloud migration is not a technology exercise—it is a structured transformation program
2. Why BFSI Migration is Complex
Migration in banking is fundamentally different because:
Regulatory constraints (RBI, GDPR, etc.)
Mission-critical systems (24x7 uptime)
Legacy dependencies
Data sensitivity (PII, financial data)
Key Challenges:
Tight coupling across systems
Batch-heavy workloads
Limited documentation
Business continuity risks
You cannot “just migrate”—you must engineer the migration
3. The Foundation: 6R Migration Strategy
Every application must be evaluated using the 6R framework.
🔷 6R Explained
Strategy | Meaning | When to Use |
Rehost | Lift & Shift | Quick migration, low change |
Replatform | Minor optimization | Cloud-native DB, runtime |
Refactor | Code change | Microservices, modernization |
Rearchitect | Full redesign | Strategic systems |
Replace | SaaS adoption | COTS replacement |
Retire | Decommission | No business value |
4. 6R Decision Framework
🔷 Decision Flow
Application → Business Criticality → Technical Complexity → Target State → 6R Strategy🔷 Example
Application | Decision |
Legacy Reporting | Retire |
CRM | Replace (SaaS) |
Lending Core | Rearchitect |
Middleware | Replatform |
Wrong 6R decision = migration failure
5. Migration Factory: The Game Changer
Large enterprises fail when migration is handled as individual projects.
🔥 Solution: Migration Factory
A standardized, scalable, assembly-line model for cloud migration
🔷 Why Migration Factory Works
Repeatable processes
Standard templates
Parallel execution
Predictable outcomes
6. Migration Factory Architecture
┌──────────────────────────────────────────────┐│ MIGRATION FACTORY GOVERNANCE │
│ PMO | Architecture | Security | Compliance │
└────────────────────┬─────────────────────────┘
▼
┌──────────────────────────────────────────────┐
│ DISCOVERY & ASSESSMENT │
│ App Inventory | Dependency Mapping │
└────────────────────┬─────────────────────────┘
▼
┌──────────────────────────────────────────────┐
│ WAVE PLANNING & PRIORITIZATION │
│ 6R Strategy | Business Alignment │
└────────────────────┬─────────────────────────┘
▼
┌──────────────────────────────────────────────┐
│ MIGRATION EXECUTION PODS │
│ Dev | Infra | QA | Security | DevOps │
└────────────────────┬─────────────────────────┘
▼
┌──────────────────────────────────────────────┐
│ VALIDATION & TESTING PIPELINE │
│ Functional | Performance | Security │
└────────────────────┬─────────────────────────┘
▼
┌──────────────────────────────────────────────┐
│ CUTOVER & DEPLOYMENT │
│ Blue-Green | Canary | Rollback │
└────────────────────┬─────────────────────────┘
▼
┌──────────────────────────────────────────────┐
│ OPTIMIZATION & CLOUD FINOPS │
│ Cost | Performance | Scaling │
└──────────────────────────────────────────────┘
7. Migration Lifecycle (Step-by-Step)
🔷 Step 1: Discovery & Assessment
Activities:
Application inventory
Dependency mapping
Infra & DB analysis
Business criticality
Output:
Application catalog
Dependency graph
Risk classification
You cannot migrate what you don’t understand
🔷 Step 2: Application Assessment & 6R Mapping
Evaluate:
Business value
Technical debt
Cloud readiness
Compliance needs
Output:
6R classification
Migration complexity score
🔷 Step 3: Wave Planning
Applications are grouped into waves.
Wave Strategy:
Wave | Type |
Wave 1 | Low-risk apps |
Wave 2 | Medium complexity |
Wave 3 | Core systems |
Start small, scale fast
🔷 Step 4: Landing Zone Setup
Cloud Foundation Includes:
VPC / Networking
IAM / RBAC
Security policies
Monitoring & logging
DevSecOps pipelines
Without landing zone, migration becomes chaos
🔷 Step 5: Migration Execution
Approaches:
Rehost using automation
Replatform DB/services
Refactor into microservices
Tools:
Infrastructure as Code (Terraform)
CI/CD pipelines
Containerization (Docker, Kubernetes)
🔷 Step 6: Testing & Validation
Types:
Functional testing
Performance testing
Security testing
Data validation
Testing is non-negotiable in BFSI
🔷 Step 7: Cutover Strategy**
Techniques:
Blue-Green deployment
Canary releases
Parallel run
Key Focus:
Zero downtime
Rollback readiness
🔷 Step 8: Optimization (FinOps)**
Post-migration:
Cost optimization
Autoscaling
Performance tuning
Cloud cost without governance = new problem
8. Migration Accelerators (Your Differentiation)
🔷 What You Should Highlight
Assessment templates
Automation scripts
Migration runbooks
Validation frameworks
Cost dashboards
These are what make migration scalable and repeatable
9. Governance in Migration
🔷 Governance Layers:
Architecture Review Board
Security approvals
Compliance validation
Risk tracking
🔷 Control Flow
Plan → Review → Approve → Execute → Audit10. Risk Management
Key Risks:
Data loss
Downtime
Performance degradation
Compliance violations
Mitigation:
Backup strategy
Rollback plans
Parallel environments
Monitoring
11. Real Enterprise Example
Scenario:
Migrating 400+ applications
Approach:
Portfolio rationalization (TIME + 6R)
Migration factory setup
Wave-based execution
Parallel squads
Outcome:
30% cost reduction
Faster deployments
Improved scalability
12. Key Success Factors
✔ Strong discovery phase
✔ Correct 6R decisions
✔ Migration factory model
✔ Automation-first approach
✔ Governance & compliance alignment
13. Common Mistakes
❌ Treating migration as lift-and-shift only❌ Ignoring dependencies❌ No governance model❌ No cost optimization strategy❌ No rollback plan
14. Final Thought
Cloud migration is not about moving applications.It is about transforming how technology is built, deployed, and operated.
🔥 Chapter 8 Summary
You now have:
✔ 6R strategy (clear and practical)
✔ Migration factory model
✔ End-to-end lifecycle
✔ Governance & risk framework
✔ Real enterprise execution model
Comments