================================================================================
MIGRATION PLAN: 21031930da18
================================================================================
Source System: Legacy User Service (Java Spring Boot 2.x)
Target System: New User Service (Node.js + TypeScript)
Migration Type: SERVICE
Complexity Level: CRITICAL
Estimated Duration: 500 hours (20.8 days)
Created: 2026-02-16T13:47:34.565896

MIGRATION PHASES
----------------------------------------
1. INTERCEPT (100h)
   Description: Execute intercept phase
   Risk Level: MEDIUM
   Tasks:
     • Complete intercept activities
   Success Criteria:
     ✓ Intercept phase completed successfully

2. IMPLEMENT (100h)
   Description: Execute implement phase
   Risk Level: MEDIUM
   Dependencies: intercept
   Tasks:
     • Complete implement activities
   Success Criteria:
     ✓ Implement phase completed successfully

3. REDIRECT (100h)
   Description: Execute redirect phase
   Risk Level: MEDIUM
   Dependencies: implement
   Tasks:
     • Complete redirect activities
   Success Criteria:
     ✓ Redirect phase completed successfully

4. VALIDATE (100h)
   Description: Execute validate phase
   Risk Level: MEDIUM
   Dependencies: redirect
   Tasks:
     • Complete validate activities
   Success Criteria:
     ✓ Validate phase completed successfully

5. RETIRE (100h)
   Description: Execute retire phase
   Risk Level: MEDIUM
   Dependencies: validate
   Tasks:
     • Complete retire activities
   Success Criteria:
     ✓ Retire phase completed successfully

RISK ASSESSMENT
----------------------------------------
HIGH SEVERITY RISKS:
  • Service compatibility issues
    Category: technical
    Probability: medium | Impact: high
    Mitigation: Implement comprehensive integration testing
    Owner: Development Team

  • Feature parity gaps
    Category: business
    Probability: high | Impact: high
    Mitigation: Document feature mapping and acceptance criteria
    Owner: Product Owner

  • Zero-downtime requirement increases complexity
    Category: business
    Probability: high | Impact: medium
    Mitigation: Implement blue-green deployment or rolling update strategy
    Owner: DevOps Team

  • Regulatory compliance requirements
    Category: compliance
    Probability: medium | Impact: high
    Mitigation: Ensure all compliance checks are integrated into migration process
    Owner: Compliance Team

MEDIUM SEVERITY RISKS:
  • Performance degradation
    Category: technical
    Probability: medium | Impact: medium
    Mitigation: Conduct load testing and performance benchmarking
    Owner: DevOps Team

  • Monitoring gap during transition
    Category: operational
    Probability: medium | Impact: medium
    Mitigation: Set up dual monitoring and alerting systems
    Owner: SRE Team

ROLLBACK STRATEGY
----------------------------------------
Rollback Triggers:
  • Critical system failure
  • Data corruption detected
  • Migration timeline exceeded by > 50%
  • Business-critical functionality unavailable
  • Security breach detected
  • Stakeholder decision to abort

Rollback Phases:
  RETIRE:
    - Revert retire changes
    - Restore pre-retire state
    - Validate retire rollback success
    Estimated Time: 1500 minutes

  VALIDATE:
    - Revert validate changes
    - Restore pre-validate state
    - Validate validate rollback success
    Estimated Time: 1500 minutes

  REDIRECT:
    - Revert redirect changes
    - Restore pre-redirect state
    - Validate redirect rollback success
    Estimated Time: 1500 minutes

  IMPLEMENT:
    - Revert implement changes
    - Restore pre-implement state
    - Validate implement rollback success
    Estimated Time: 1500 minutes

  INTERCEPT:
    - Revert intercept changes
    - Restore pre-intercept state
    - Validate intercept rollback success
    Estimated Time: 1500 minutes

SUCCESS CRITERIA
----------------------------------------
✓ All data successfully migrated with 100% integrity
✓ System performance meets or exceeds baseline
✓ All business processes functioning normally
✓ No critical security vulnerabilities introduced
✓ Stakeholder acceptance criteria met
✓ Documentation and runbooks updated

STAKEHOLDERS
----------------------------------------
• Business Owner
• Technical Lead
• DevOps Team
• QA Team
• Security Team
• End Users
