API Gateway & Service Mesh Deep Dive (Control Plane, Data Plane, Traffic Management, Istio)

#Glossary (Thuật ngữ nâng cao)

• API Gateway: entry point cho client (north-south)
• Service Mesh: giao tiếp nội bộ (east-west)
• Control Plane: quản lý config
• Data Plane: xử lý request (proxy)
• Sidecar: proxy đi kèm service
• Service Discovery: tìm service runtime
• Circuit Breaker: ngắt request khi lỗi

#1. Bản chất hệ thống

Gateway + Mesh = control layer của distributed system

#2. Control Plane vs Data Plane (CỰC QUAN TRỌNG)

#Data Plane

• Envoy proxy xử lý request

#Control Plane

• push config xuống proxy

#Insight

Control plane quyết định behavior Data plane thực thi

#3. Traffic Flow

Client → Gateway → Service A → Proxy → Proxy → Service B

#4. Traffic Management (Deep)

#4.1 Canary Release

• deploy version mới cho 10% user

#4.2 Blue-Green

• switch toàn bộ traffic

#4.3 Traffic Shifting

v1: 90%
v2: 10%

#Insight

giảm risk deploy

#5. Service Discovery

#Problem

• IP service thay đổi

#Solution

• service registry

#Flow

service register → gateway lookup → route

#6. Retry + Timeout + Circuit Breaker (Deep)

#Problem

config sai → DDOS nội bộ

#Example

retry: 3
timeout: 2s
breaker: open after 5 fails

#Interaction

• retry nhiều + timeout dài → overload

#Insight

retry phải đi cùng timeout + breaker

#7. Sidecar Pattern (Deep)

Service + Envoy sidecar

👉 intercept toàn bộ traffic

#8. Observability (Deep)

#Metrics

• latency
• error rate

#Tracing

• distributed tracing (request flow)

#Logging

• centralized log

#Correlation ID

• trace request xuyên system

#9. Security (Deep)

#mTLS

• encrypt nội bộ

#Auth at Gateway

• JWT validate

#10. Failure Matrix (Cực sâu)

#11. Real Incident

#Case 1: Cascading Failure

• service A chậm → B chờ → C chờ → system sập

#Fix

• timeout + breaker

#Case 2: Retry Storm

• retry đồng loạt

#Case 3: Bad Config Deploy

• config sai → toàn system lỗi

#12. Scaling Strategy

#13. Cost

• proxy tốn CPU/RAM

#Trade-off

• observability vs cost

#14. Advanced Patterns

#Rate Limit tại Gateway

• global control

#API Aggregation

• combine nhiều service

#Fault Injection

• simulate failure

#15. Checklist Production

• control/data plane
• traffic management
• service discovery
• retry + breaker
• observability

#16. Final Architect Insight

Gateway + Mesh = hệ thần kinh của microservices

Trade-off:

• complexity
• latency
• cost