Microservices principle # 5: Business capabilities

You should build your microservice around business capabilities. Each service should be responsible for a specific business capability, and all the services together should be able to cover all the business capabilities your application needs.

This principle is important for several reasons:

  • It helps keep your services small and manageable. If each service is responsible for just one business capability, it will be easier to understand and change as needed.
  • It helps ensure that the developer's application can scale. If each service can be scaled independently, developers can scale the parts of their application that need more resources without affecting the other parts.
  • This principle can help developers build more fault-tolerant applications. If one service fails, the others keep working and providing the necessary business capabilities. This can help minimize the impact of failures and downtime on your users.

Microservices principle # 6: Decentralization

Unlike monolithic applications, in microservices-based applications each service maintains its own copy of the data. Ideally, each microservice should have its own database. Multiple services accessing or sharing the same database defeat the purpose of microservices architecture.

This would allow programmers to have centralized access control while seamlessly implementing audit logging and caching. It would also let developers centralize access control, as well as easily implement audit logging and caching. Ideally, you should have one or two database tables per service.

Microservices principle # 7: Process automation

Process automation is an important principle of microservices architecture. By automating processes, programmers can improve reliability, reduce costs, and speed up software development cycles. Unlike a monolithic application, a microservices-based application requires you to manage multiple deployment units.

Therefore, you should be able to automate the deployment process for your microservices-based application. You can do this by adopting a DevOps culture in your organization and using the right tools, such as Azure DevOps or Jenkins.

Microservices principle # 8: Communication between services

When you break an existing monolithic application into microservices, you also need to define how those services will communicate. Since microservices architecture lets you use heterogeneous technologies, how can these services communicate with each other? This is where application programming interfaces (APIs) can help.

There are several ways to implement communication between services in a microservices architecture. One solution is to use an event-driven approach, where one service publishes an event that another service can subscribe to and respond to accordingly.

Another option is to use a messaging protocol such as HTTP or AMQP, so messages can be exchanged between services without requiring any details about their implementation. Programmers should encapsulate the technical details of how their service works internally and provide API functions so other services (internal, external, or both) can access their service through these API methods. By doing so, they ensure their service can grow on its own over time without compromising encapsulation.

Microservices principle # 9: Monitoring

Because of the distributed nature of microservices-based applications, finding errors through a manual process is a challenging task. That's why you need an automated monitoring system. Monitoring in a microservices architecture is complicated, and not just because there are more moving parts. The challenge with monitoring microservices is that they are designed to be independent of one another, which means they are often built using different technologies and environments. This makes it difficult to figure out how to monitor the system as a whole.

Monitoring in a microservices architecture is a little different from monitoring in a monolithic architecture. Since each microservice is a separate entity, multiple instances of each service may be running at any given time.

This means there are more metrics to track and more logs to examine. The monitoring system should be able to collect and analyze data, as well as generate useful metrics.

Microservices principle # 10: Command Query Responsibility Segregation (CQRS)

Traffic to services in a microservices-based application can vary. You may have a service with huge traffic, while another may have low traffic. In this regard, developers should take advantage of autoscaling and circuit breakers. Command Query Responsibility Segregation (CQRS) is a design pattern that separates read and write operations into distinct classes. This lets you scale read and write operations independently, which can be especially useful for microservices architectures. The CQRS pattern is commonly used in microservices architecture.

This is because it allows different components to be responsible for other parts of an application's functionality, making it easier to scale and maintain. Since data access in the CQRS design pattern is limited to a single database, it can be useful for complex queries spanning multiple service databases. This design has two sections: command and query.

The command component will be responsible for creating, editing, and deleting records, while the query component will be responsible for reading them. This approach has several advantages. First, it lets you scale reads independently of writes.

For example, if your application has many write operations but few read operations, you can create several instances of the write layer and then have one instance of the read layer. Another advantage is that it's easier to manage data integrity when each class has its own responsibility.

A third advantage is that it makes your code more testable, since each class will have only one responsibility instead of many, as is usually the case with many-to-many relationships in relational databases.

To sum up

Developers can address the challenges that arise when building a microservices architecture by following the right design principles, so they can build modern, easily scalable applications.