Architecture Overview

graph TB subgraph "External Layer" LB[Load Balancer] DNS[DNS] end subgraph "Ingress Layer" IG[Istio Gateway] subgraph "Service Mesh" Envoy[Envoy Proxies] end end subgraph "Application Layer" App1[Service 1] App2[Service 2] App3[Service N] FastAPI[FastAPI Example] end subgraph "Data Layer" subgraph "Caching" Redis[Redis
Master + Replicas] end subgraph "Relational" PG[PostgreSQL
Cluster] MySQL[MySQL
Cluster] end subgraph "Document" Mongo[MongoDB
Replica Set] end end subgraph "Messaging Layer" Kafka[Kafka
Brokers] ZK[Zookeeper
Ensemble] end subgraph "Observability Layer" OTel[OpenTelemetry
Collector] Jaeger[Jaeger
Tracing] Prom[Prometheus
Metrics] Grafana[Grafana
Dashboards] end DNS --> LB LB --> IG IG --> Envoy Envoy --> App1 Envoy --> App2 Envoy --> App3 Envoy --> FastAPI App1 --> Redis App1 --> PG App2 --> MySQL App3 --> Mongo FastAPI --> Redis FastAPI --> PG FastAPI --> MySQL FastAPI --> Mongo App1 --> Kafka App2 --> Kafka App3 --> Kafka FastAPI --> Kafka Kafka --> ZK App1 --> OTel App2 --> OTel App3 --> OTel FastAPI --> OTel OTel --> Jaeger OTel --> Prom Grafana --> Prom Grafana --> Jaeger style IG fill:#326CE5 style Envoy fill:#326CE5 style Redis fill:#DC382D style PG fill:#336791 style MySQL fill:#4479A1 style Mongo fill:#47A248 style Kafka fill:#231F20 style OTel fill:#FF6F00 style Jaeger fill:#60D0E4 style Prom fill:#E6522C style Grafana fill:#F46800

sequenceDiagram participant Client participant Istio Gateway participant Envoy Sidecar participant Application participant Database participant OTel Collector participant Jaeger Client->>Istio Gateway: HTTPS Request Istio Gateway->>Envoy Sidecar: Forward Request Note over Envoy Sidecar: mTLS Encryption Envoy Sidecar->>Application: HTTP Request Note over Application: Generate Trace Application->>Database: Query Data Database-->>Application: Return Data Application->>OTel Collector: Send Trace OTel Collector->>Jaeger: Store Trace Application-->>Envoy Sidecar: HTTP Response Envoy Sidecar-->>Istio Gateway: Forward Response Istio Gateway-->>Client: HTTPS Response

graph LR subgraph "Application" App[Application Code] OTelSDK[OpenTelemetry SDK] end subgraph "Collection" Collector[OTel Collector] end subgraph "Storage & Visualization" Jaeger[Jaeger
Traces] Prometheus[Prometheus
Metrics] Grafana[Grafana
Dashboards] end App -->|Instrument| OTelSDK OTelSDK -->|OTLP/gRPC| Collector Collector -->|Traces| Jaeger Collector -->|Metrics| Prometheus Prometheus -->|Query| Grafana Jaeger -->|Query| Grafana style App fill:#009688 style Collector fill:#FF6F00 style Jaeger fill:#60D0E4 style Prometheus fill:#E6522C style Grafana fill:#F46800

graph TD App[Application] subgraph "Data Access" Cache{Check Cache} Redis[Redis] DB{Select DB} PG[PostgreSQL] MySQL[MySQL] Mongo[MongoDB] end App --> Cache Cache -->|Hit| App Cache -->|Miss| DB DB -->|Relational| PG DB -->|Alternative| MySQL DB -->|Document| Mongo PG --> App MySQL --> App Mongo --> App style Cache fill:#FFD700 style Redis fill:#DC382D style PG fill:#336791 style MySQL fill:#4479A1 style Mongo fill:#47A248

graph LR subgraph "Producers" Service1[Service 1] Service2[Service 2] Service3[Service 3] end subgraph "Message Broker" Kafka[Kafka Cluster] Topics[Topics:
- orders
- events
- notifications] end subgraph "Consumers" Consumer1[Consumer 1] Consumer2[Consumer 2] Consumer3[Consumer 3] end Service1 -->|Publish| Kafka Service2 -->|Publish| Kafka Service3 -->|Publish| Kafka Kafka --> Topics Topics -->|Subscribe| Consumer1 Topics -->|Subscribe| Consumer2 Topics -->|Subscribe| Consumer3 style Kafka fill:#231F20,color:#fff style Topics fill:#231F20,color:#fff

graph TB subgraph "Scaling Tiers" subgraph "Stateless - Scale Freely" API[API Services
2-10 replicas] OTel[OTel Collectors
2-5 replicas] end subgraph "Stateful - Controlled Scaling" Redis[Redis
1 Master + N Replicas] PG[PostgreSQL
3-7 nodes] Kafka[Kafka
3-9 brokers] end end HPA[Horizontal Pod
Autoscaler] HPA -->|Auto Scale| API HPA -->|Auto Scale| OTel style API fill:#4CAF50 style OTel fill:#FF6F00 style Redis fill:#DC382D style PG fill:#336791 style Kafka fill:#231F20,color:#fff

graph TB subgraph "Region: us-west-2" subgraph "AZ-1" K8s1[Kubernetes Node] PG1[PostgreSQL-0] Kafka1[Kafka-0] App1[App Replicas] end subgraph "AZ-2" K8s2[Kubernetes Node] PG2[PostgreSQL-1] Kafka2[Kafka-1] App2[App Replicas] end subgraph "AZ-3" K8s3[Kubernetes Node] PG3[PostgreSQL-2] Kafka3[Kafka-2] App3[App Replicas] end end LB[Load Balancer] LB --> App1 LB --> App2 LB --> App3 PG1 -.->|Replicate| PG2 PG2 -.->|Replicate| PG3 PG3 -.->|Replicate| PG1 Kafka1 -.->|Replicate| Kafka2 Kafka2 -.->|Replicate| Kafka3 Kafka3 -.->|Replicate| Kafka1 style LB fill:#326CE5 style K8s1 fill:#326CE5 style K8s2 fill:#326CE5 style K8s3 fill:#326CE5

graph TB subgraph "External" Client[Client] end subgraph "Edge Security" WAF[WAF] Gateway[Istio Gateway
TLS Termination] end subgraph "Service Mesh" subgraph "mTLS Zone" Service1[Service 1
+ Envoy] Service2[Service 2
+ Envoy] Service3[Service 3
+ Envoy] end end subgraph "Data Security" Secrets[Sealed Secrets] Encryption[Encryption at Rest] end subgraph "Access Control" RBAC[Kubernetes RBAC] NetworkPolicy[Network Policies] end Client -->|HTTPS| WAF WAF -->|HTTPS| Gateway Gateway -.->|mTLS| Service1 Gateway -.->|mTLS| Service2 Gateway -.->|mTLS| Service3 Service1 -.->|mTLS| Service2 Service2 -.->|mTLS| Service3 Secrets --> Service1 Secrets --> Service2 Secrets --> Service3 RBAC --> Service1 RBAC --> Service2 RBAC --> Service3 NetworkPolicy --> Service1 NetworkPolicy --> Service2 NetworkPolicy --> Service3 style WAF fill:#F44336 style Gateway fill:#326CE5 style Secrets fill:#9C27B0 style RBAC fill:#FF9800 style NetworkPolicy fill:#FF9800

graph LR subgraph "Ephemeral Storage" EmptyDir[EmptyDir
Temporary data] end subgraph "Persistent Storage" PVC[PersistentVolumeClaim] PV[PersistentVolume] Storage[Cloud Storage
EBS, Persistent Disk, etc.] end Pod[Pod] --> EmptyDir Pod --> PVC PVC --> PV PV --> Storage style EmptyDir fill:#FFC107 style PVC fill:#2196F3 style PV fill:#2196F3 style Storage fill:#4CAF50