Microservices, often referred to as the microservices architecture, is an architectural style that structures an application as a collection of small, independent, and loosely coupled services. Each service is responsible for a specific functionality and can be developed, deployed, and scaled independently. The components and concepts associated with microservices include:
Individual Service/Component: The core of the microservices model. Each microservice is a small application with its specific business logic.
Service Database: Each microservice can have its database to ensure that the services are decoupled from each other. This pattern ensures data consistency and integrity within the respective service.
API Gateway: Acts as the entry point for clients. It is responsible for request routing, composition, and request/response transformation. The API gateway can handle authentication, provide consistent response formats, or aggregate responses from multiple microservices.
Service Discovery: As microservices can be dynamically located in different servers or containers, service discovery tools help in locating and calling the appropriate service instance. Examples include Eureka, Consul, and Zookeeper.
Load Balancer: Helps distribute incoming application traffic across multiple instances of a microservice. It improves the distribution of workloads across multiple computing resources and aims to optimize resource use, maximize throughput, minimize response time, and prevent overload on any single resource.
Configuration Server: Centralized external configuration management helps microservices run in different environments.
Circuit Breaker: Provides resilience in a distributed system. When a microservice fails, the circuit breaker prevents cascading failure by failing fast and redirecting or halting the request chain.
Service Mesh: Examples like Istio or Linkerd help in handling service-to-service communication, load balancing, circuit breaking, policy enforcement, etc., in a more decentralized fashion.
Containerization: Microservices often run inside containers. Docker is the most popular containerization tool, and Kubernetes is a commonly used orchestration platform.
Centralized Logging and Monitoring: Due to the distributed nature of microservices, centralized logging (like ELK stack) and monitoring (like Prometheus) tools are essential to detect and troubleshoot issues.
Continuous Integration/Continuous Deployment (CI/CD): Given the independently deployable nature of microservices, automation of the build and deployment process becomes critical. Tools like Jenkins, Travis CI, and GitLab CI help facilitate this.
Authentication and Authorization: Security can be handled at the microservice level, where each service can be responsible for its authentication and authorization, or it can be managed at the API Gateway level.
Event-Driven Architecture: Often, microservices communicate asynchronously using events. Systems like Apache Kafka or RabbitMQ can be used for this kind of communication.
Versioning: As microservices evolve, versioning helps in ensuring backward compatibility and smooth transitions.
Health Check API: Endpoints within the microservice that allow automated systems and operations teams to check the health and status of the application.
Remember, while the above components and practices are commonly associated with microservices, it doesn’t mean every microservices-based application must use all of them. The architecture can be tailored based on specific project needs.