cloudthinker-ai Monolith to Serverless Migration Plan
Phase 1: Domain Analysis
- Map the monolith's bounded contexts
- Identify distinct business domains within the application
- Document data ownership per domain
- Map synchronous and asynchronous communication patterns
- Identify shared libraries and cross-cutting concerns
- Assess each domain for serverless suitability
Serverless Suitability Matrix
| Domain | Stateless | Event-Driven | Short-Lived | Cold Start OK | Serverless Fit |
|---|---|---|---|---|---|
| [ ] | [ ] | [ ] | [ ] | High/Med/Low |
Phase 2: Architecture Design
- Design event-driven architecture with message broker
- Define API Gateway routes and function mappings
- Plan state management strategy (database per function vs. shared)
- Design authentication and authorization flow
- Plan for cold start mitigation (provisioned concurrency, warm-up)
Component Mapping
| Monolith Component | Serverless Target | Trigger Type | State Store |
|---|---|---|---|
| Function/Step Function/Container | HTTP/Event/Schedule |
Phase 3: Infrastructure Setup
- Provision serverless platform and supporting services
- Set up API Gateway with routing rules
- Configure event bus or message queue
- Set up databases per domain (DynamoDB, Firestore, etc.)
- Implement shared layers/extensions for common code
- Configure monitoring and distributed tracing
Phase 4: Incremental Extraction (Strangler Fig)
- Start with the lowest-risk, most independent domain
- Extract domain logic into serverless functions
- Route traffic through API Gateway with fallback to monolith
- Validate behavior matches monolith
- Repeat for each domain in priority order
Phase 5: Data Migration
- Migrate data from monolith database to domain-specific stores
- Implement data synchronization during transition period
- Handle cross-domain queries with aggregation patterns
- Validate data consistency across services
Phase 6: Optimization & Finalization
- Remove extracted code from monolith
- Optimize function memory and timeout settings
- Implement cost monitoring per function
- Set up auto-scaling policies
- Decommission monolith after all domains extracted
Counter-Rationalizations
| Shortcut | Counter | Why |
|---|---|---|
| "We can skip some steps for this case" | Adapt the workflow steps, don't skip them | Skipped steps are where incidents and oversights originate |
| "The user seems to already know what to do" | Complete all workflow phases with the user | The workflow catches blind spots that experience alone misses |
| "This is a minor case, full process is overkill" | Scale the process down, don't turn it off | Minor cases become major when unstructured; the process scales, not disappears |
| "I'll fill in the details later" | Complete each section before moving on | Deferred details are forgotten; real-time capture is more accurate |
| "The template output isn't necessary" | Always produce the structured output format | Structured output enables comparison, audit trails, and handoff to other teams |
Output Format
- Domain Map: Bounded contexts with dependencies and data ownership
- Architecture Diagram: Serverless target architecture with event flows
- Function Catalog: List of all functions with triggers, inputs, outputs
- Migration Sequence: Ordered extraction plan with dependencies
- Cost Projection: Expected serverless costs vs. current infrastructure
Action Items
- Complete domain analysis and boundary identification
- Design target serverless architecture
- Extract first domain as proof of concept
- Validate performance and cost projections
- Execute remaining domain extractions in priority order
- Decommission monolith after full migration