What are microservices? How do they differ from monolithic architecture?

What Are Microservices?

Microservices, also known as the microservices architecture, is an architectural style that structures an application as a collection of small, autonomous services modeled around a business domain. Each microservice is a self-contained unit that performs a specific function within the application. These services communicate with each other using lightweight protocols, often HTTP/REST or messaging queues.

Key Characteristics of Microservices:

1. Independence: Each microservice can be developed, deployed, and scaled independently.
2. Single Responsibility: Each service focuses on a single business capability.
3. Decentralized Data Management: Each microservice may manage its own database, which helps avoid the complexities of shared databases.
4. Lightweight Communication: Services communicate with each other through APIs, typically RESTful or messaging protocols like RabbitMQ.
5. Resilience: Microservices are designed to be fault-tolerant, meaning that the failure of one service should not cause the entire system to fail.

Differences from Monolithic Architecture:

1. Architecture:

   • Monolithic: A single, unified codebase where all components of the application are tightly coupled and run as a single process.
   • Microservices: A collection of loosely coupled services that interact over a network.

2. Deployment:

   • Monolithic: Deployed as a single unit. Any change requires the entire application to be redeployed.
   • Microservices: Each service can be deployed independently, enabling more frequent and less risky deployments.

3. Scalability:

   • Monolithic: Scaling requires scaling the entire application, even if only one part of it is under heavy load.
   • Microservices: Individual services can be scaled independently, allowing more efficient use of resources.

4. Development:

   • Monolithic: A single team often handles development, leading to potential bottlenecks as the codebase grows.
   • Microservices: Different teams can work on different services concurrently, often using different programming languages or technologies.

5. Flexibility:

   • Monolithic: Changes in one part of the application may require extensive changes in other parts.
   • Microservices: Changes are isolated to individual services, reducing the impact on the overall system.

6. Fault Isolation:

   • Monolithic: A failure in one part of the application can potentially bring down the entire system.
   • Microservices: Failures are isolated to individual services, which reduces the risk of a system-wide outage.

In summary, microservices provide a way to build and maintain complex applications with greater flexibility, scalability, and resilience, but they also introduce complexity in areas such as inter-service communication, data consistency, and overall system management.