What is a microservices architecture?

Back-end development has evolved rapidly over the years to meet the growing needs for flexibility, maintainability, and application performance.

One of the approaches that has established itself in the software development world is microservices architecture.

This architectural model stands in contrast to the more classic 3-tier architecture, and brings significant benefits for large-scale projects!

But what exactly is a microservice?

That's what we'll discover together by understanding the basics of this architecture, its advantages, its drawbacks, and some use cases.

Definition of a microservice

A microservice is a small, self-contained application that manages a set of functions related to a specific business domain, within a larger system.

In a microservices architecture, a complete application is broken down into a series of independent services.

These "micro" services communicate with each other over the network, often through the HTTP protocol or other messaging/event protocols.

Each microservice is designed to accomplish a well-defined task, such as:

• user management
• billing
• authentication
• order processing
• etc...

Unlike a 3-tier architecture, where all these functions are managed by a single codebase to handle the logic, and deployed on a single server.

A key point of microservices is their independence.

Each service can be developed, tested, deployed, and updated independently of the others.

This notably allows a development team to iterate quickly on one part of the software without affecting other parts, but that's far from the only advantage of this architecture.

The advantages of microservices

1. Modularity and maintainability: The main advantage of microservices is modularity. Each service is responsible for a specific task, which makes the code easier to understand, maintain, and evolve.
2. Scaling: One of the major challenges of a monolithic architecture is scalability. With microservices, it's possible to scale each service individually according to its specific needs. For example, if a user management service receives more traffic, it can be scaled independently of the other services.
3. Technological flexibility: Microservices allow developers to choose the best technology for each service. One service can be developed in Java, another in Python, and yet another in Node.js. This flexibility makes it possible to leverage the strengths of each language or framework for the specific needs of each component.
4. Independent deployment: As mentioned earlier, each microservice can be deployed independently, which enables more frequent and safer updates. If part of the system fails or needs to be modified, this doesn't necessarily affect the entire application.
5. Resilience: If a service goes down in a microservices architecture, this doesn't necessarily cause the entire application to fail. The other services continue to run, making the overall system more resilient to errors.

The drawbacks of microservices

A microservices architecture isn't suitable for all projects, particularly because it has some significant drawbacks:

1. Increased complexity: Developing and maintaining a microservices architecture can prove complex, especially when it comes to managing communication between services.

It's often necessary to use additional tools to orchestrate and monitor interactions between the different microservices.

2. Distributed data management: Each service may have its own database, which complicates transaction management and data consistency across services.
3. Debugging and traceability: Debugging a microservices system is often more difficult than debugging a monolith. With multiple services interacting with each other, it can be complex to trace the flow of a request through the different parts of the system.
4. Deployment: Since each microservice requires independent resources and instances, deployment can quickly become complex and infrastructure costs can increase compared to a monolithic application running on a single server.

A use case

Some tech giants today use microservices to ensure the scalability and flexibility of their systems.

This is, for example, the case with Netflix.

Netflix, like all other VOD platforms, faces very large computing power needs for very specific modules, such as video encoding, for example.

Meanwhile, on the other side, managing other APIs like the list of categories, movies, settings, etc… requires very few resources.

Microservices architecture therefore makes it possible to have a myriad of small services provisioned on servers that are just powerful enough to handle the user load, and a few massive services distributed across gigantic data centers for video processing!

Conclusion

While they bring many advantages such as scalability, resilience, and the ability to scale targeted services, microservices also introduce a layer of complexity that shouldn't be underestimated in managing a project.

As with any architecture, the decision should be made based on the project's constraints and needs, and not based on the popularity of the architecture in question.