Microservices Knowledge Enrichment
Additional patterns and concepts to complement the architecture plan.
What You Have Covered Well
- Core patterns (Outbox, CQRS, Event Sourcing, Saga)
- Resilience (Circuit Breaker, Bulkhead, Retry)
- Observability stack
- Security layers
- Event contract structure
Gaps & Enrichment Areas
1. Domain-Driven Design (DDD)
Missing foundational concepts that drive good service boundaries:
| Concept |
Why It Matters |
| Bounded Contexts |
Defines service boundaries, prevents coupling |
| Aggregates |
Consistency boundaries within a service |
| Context Mapping |
How services/teams interact (ACL, Shared Kernel) |
| Anti-Corruption Layer |
Isolates legacy/external systems |
2. Service Discovery
Not mentioned - how do services find each other?
- Kubernetes DNS (if K8s-native)
- Consul / Eureka (traditional)
- Istio Service Registry (since you have Istio)
3. Communication Patterns
You have RabbitMQ but could add:
| Pattern |
Use Case |
| gRPC |
High-performance inter-service calls |
| GraphQL Federation |
Unified API across services |
| Orchestration Saga |
MassTransit state machines (vs choreography) |
| Backpressure |
When consumers can't keep up |
4. Deployment Patterns
| Pattern |
Description |
| Blue/Green |
Zero-downtime deployment |
| Canary Releases |
Gradual rollout to subset of users |
| Rolling Updates |
K8s native approach |
| Strangler Fig |
Incremental migration from monolith |
5. Data Patterns
| Pattern |
Description |
| Database per Service |
State this explicitly as a principle |
| API Composition |
Aggregating data from multiple services |
| Materialized Views |
Pre-computed read models (beyond Redis cache) |
| CDC |
You have Debezium, but worth documenting the pattern |
6. Resilience Additions
| Pattern |
Description |
| Load Shedding |
Rejecting requests under pressure |
| Fallback |
Default responses when dependencies fail |
| Timeout Propagation |
Deadline propagation across services |
| Poison Message Handling |
Beyond DLQ - alerting, manual replay |
7. Observability Maturity
| Concept |
What to Add |
| SLIs/SLOs/SLAs |
Define concrete targets (latency, error rate) |
| Error Budgets |
Balance reliability vs velocity |
| Alerting Strategy |
Symptom-based vs cause-based alerts |
| Runbooks |
Operational playbooks for incidents |
8. Security Additions
| Concept |
Description |
| Zero Trust |
Never trust, always verify |
| OIDC Flows |
Authorization Code, Client Credentials |
| Input Validation |
At service boundaries |
| Rate Limiting per Tenant |
Beyond global rate limits |
9. Anti-Patterns to Document
| Anti-Pattern |
Why Avoid |
| Distributed Monolith |
Tightly coupled "microservices" |
| Shared Database |
Breaks service autonomy |
| Chatty Services |
N+1 calls between services |
| Synchronous Chains |
A→B→C→D creates fragility |
10. Testing Enrichment
| Type |
Tool/Approach |
| Consumer-Driven Contracts |
Pact (you have it, but document the workflow) |
| Service Virtualization |
WireMock, Mountebank |
| Synthetic Monitoring |
Production health checks |
11. Multi-Tenancy
If applicable:
- Tenant isolation strategies (DB per tenant, schema per tenant, row-level)
- Tenant-aware routing
12. Cost & Scaling
| Topic |
Description |
| Right-sizing |
CPU/memory limits based on profiling |
| HPA/VPA |
Autoscaling strategies |
| Spot/Preemptible |
Cost optimization for non-critical |
Recommended Learning Path
- DDD → Eric Evans' book, Vaughn Vernon's "Implementing DDD"
- Patterns → "Microservices Patterns" by Chris Richardson
- Resilience → "Release It!" by Michael Nygard
- Observability → "Observability Engineering" by Charity Majors