DDD (Domain Driven Design ) is the core and most important foundation of Microservices architecture. There will be a huge impact on understanding the beautify of Microservice architecture without understanding DDD. As the name implies, a microservices architecture is an approach to building a server application as a set of small services.
Each service runs in its own process and communicates with other processes using protocols such as HTTP/HTTPS, WebSockets, or AMQP. Each microservice implements a specific end-to-end domain or business capability within a certain context boundary, and each must be developed autonomously and be deployable independently.
Finally, each microservice should own its related domain data model and domain logic (sovereignty and decentralized data management).
What size should a Microservice Architecture be?
When developing a microservice, size shouldn’t be an important point. Instead, the important point should be to create loosely coupled services. Below are the benefits of loosely coupled services (for each service):
- Autonomy of Development
When identifying and designing microservices, try to make them as small as possible as long as no need to have too many direct dependencies with other microservices. More important than the size of the microservice is the internal cohesion it must have and its independence from other services.
Why a microservices architecture?
Microservices architecture applauds and speaks loudly — “I provide long-term agility.” Microservices enable better maintainability in complex, large, and highly-scalable systems by letting you create applications based on many independently deployable services that each have granular and autonomous lifecycles.
As an additional benefit, microservices can scale-out independently. Instead of having a single monolithic application that you must scale out as a unit.
Below are the important benefits:
- You can scale just the functional area that needs more processing power or network bandwidth to support demand, rather than scaling out other areas of the application that don’t need to be scaled.
- The microservices approach allows agile changes and rapid iteration of each microservice because you can change specific, small areas of complex, large, and scalable applications.
- Architecting fine-grained microservices-based applications enables continuous integration and continuous delivery practices. It also accelerates the delivery of new functions into the application.
- Fine-grained composition of applications also allows you to run and test microservices in isolation, and to evolve them autonomously while maintaining clear contracts between them.
- As long as you don’t change the interfaces or contracts, you can change the internal implementation of any microservice or add new functionality without breaking other microservices.
How does Microservice Architecture Help in Production?
The following are important aspects to enable success in going into production with a microservices-based system:
- Monitoring and health checks of the services and infrastructure.
- Scalable infrastructure for the services (that is, cloud and orchestrators).
- Security design and implementation at multiple levels: authentication, authorization, secrets management, secure communication, etc.
- Rapid application delivery, usually with different teams focusing on different microservices.
- DevOps and CI/CD practices and infrastructure.
DDD is a very important concept of microservices architecture. Event Sourcing, CQRS, API Gateway, etc. are very important parts of the microservices architect. Nowadays Docker, Kubernetes, Linux, etc. are an important part of scalability.
Docker is becoming the de-facto standard in the container industry, supported by the most significant vendors. In addition, the microservices architecture is emerging as an important approach for distributed mission-critical applications.
In a microservice-based architecture, the application is built on a collection of services that can be developed, tested, deployed, and versioned independently.