9 Core Components of Microservice Architecture

A comprehensive microservices architecture consists of several interconnected components that work together to create a scalable, maintainable, and resilient system.

1. API Gateway

The entry point for all client requests. Routes requests to appropriate services, handles cross-cutting concerns like authentication, rate limiting, and request transformation.

2. Service Registry

Maintains a registry of all available service instances and their locations. Services register themselves on startup and the registry enables service discovery.

3. Service Layer

Contains multiple independent services (Service A, B, C, etc.) each handling specific business capabilities. Services communicate through well-defined APIs.

4. Authorization Server

Handles authentication and authorization. Validates user credentials, issues tokens, and manages admin access permissions.

5. Distributed Messaging

Enables asynchronous communication between services using message queues. Provides Queue Management Interface for monitoring and managing message flow.

6. Distributed Cache

Improves performance by caching frequently accessed data. Reduces database load and improves response times.

7. Load Balancer

Distributes incoming requests across multiple service instances. Ensures no single instance is overwhelmed and provides high availability.

8. Metrics & Monitoring

• Grafana: Metrics visualization and dashboards
• Prometheus: Metrics collection and storage
• Collects metrics from all services for observability

9. Logging Stack (ELK)

• Logstash: Log collection and processing
• Elasticsearch: Log storage and indexing
• Kibana: Log visualization and analysis
• Provides centralized logging for debugging and audit trails

Data Layer

Distributed Layer

• Database replication for high availability
• Data distribution across multiple nodes

System Architecture Flow

Client → API Gateway → Service Registry
                    → Service Layer (A, B, C)
                    → Load Balancer
                    → Distributed Cache
                    → Distributed Messaging
                    → Distributed Layer (Databases)

Monitoring: Grafana ← Prometheus ← Services (Metrics)
Logging: Kibana ← Elasticsearch ← Logstash ← Services (Logs)
Security: Authorization Server ← API Gateway

Sources

• Arhitectura/microservices.gif
• Credit: Rocky Bhatia (rockybhatia.substack.com)