11 Reasons to Switch from Monolithic to Microservices

In this blog post, I will provide a brief overview of Monolithic and Microservice architectures and focus on 11 reasons why you should prefer using Microservice architecture.

Monolith vs. Microservices

Monolithic Architecture

According to ITS, a monolithic architecture is defined as;

Monolithic architecture is the traditional unified model for the design of a software program. A monolithic application is an application in which the user interface, business rules, and data access code are combined into a single executable program and deployed on one platform. It operates independently from other applications, performing every step of the process needed to complete the entire business function. It does not share any logic or data across the system or organizational boundaries. Databases are designed for access by single application systems within a single agency, not for access by multiple application systems in multiple agencies simultaneously.

Monolithic Architecture Diagram

In other words, we can briefly describe a monolithic application as self-contained and independent from other computing applications. The design philosophy is that the application is responsible for every step required to complete a particular function, rather than a particular task.

Monolithic architecture is still the most preferred software architecture today. It is especially preferred by newly established start-up companies. We can list the reasons behind this as follows:

  • Easy monitoring,
  • Quick and easy development and maintenance for small projects,
  • Consistent interoperability of the functionalities,
  • Easy transaction management.

However, as the project grows, some problems begin to arise. For example;

  • Code duplication and Git Merge complications,
  • Shared database,
  • Codebase complexity,
  • Lack of ownership of code,
  • Almost impossible regression testing,
  • No possibility to scale a specific functionality,
  • A long process from development to deployment,
  • More difficult development and maintenance with the increase in the number of teams and employees working on the project.

Additionally;

  • Due to their dependencies on each other, changes made in one functionality can affect others.
  • The same programming language and the same frameworks must be used in the application.
  • Even with a small change in the application, the entire application must be deployed.

Microservice Architecture

According to AWS, microservice architecture is defined as:

An architectural and organizational approach to software development where software is composed of small independent services that communicate over well-defined APIs. These services are owned by small, self-contained teams.

Microservice Architecture Diagram

In short, microservice can be defined as individual services that work independently from each other and communicate with each other. Each service carries out its own business logic and does not deal with the business logic of other services. It is an architecture that reduces the burden and complexity of monolithic architecture and offers easier management.

Communication between services takes place with protocols such as HTTP, HTTPS, AMQP, or a binary protocol like TCP. The appropriate protocol is selected according to the nature of the data to be transferred. Although the HTTP protocol is used in most of the applications developed in the market, the usage of AMQP protocol is increasing with the popularity of message brokers like RabbitMQ and Kafka.

The advantages of the Microservice architecture are:

  • Easy version controlling,
  • Independent databases,
  • A considerably simple code base of the service, since each service is independent of each other and only has its own business logic,
  • Strong ownership of code,
  • Possibility of regression testing,
  • Possibility to scale a specific functionality,
  • The ease of adding new features and maintaining existing code, whether the application is very large or very small because it is sufficient to make changes only within the relevant service,
  • More efficient and quicker teamwork since new employees can easily adapt without getting lost in the codebase.

Additionally,

  • Due to their dependencies on each other, changes made in one functionality can affect others.
  • Services can be written in different languages and with different frameworks.
  • Changes made to one service do not require other services to be re-deployed. It is sufficient to deploy only the relevant service.

Unfortunately, there is no silver bullet. The microservice architecture has its drawbacks that you may face:

  • Increase in system architecture complexity
  • Increase in development time for complex features
  • Complexity in communication between services

Switching from Monolithic to Microservices

As application development trends continue to evolve, the controversy between microservice architecture and monolithic architecture will only become more pronounced. In the end, developers should analyze the current situation well and understand what is actually needed for their specific use cases.

For smaller companies, starting with a monolithic architecture can be simpler, faster, and cheaper, and if the product is not very mature, it can be switched to microservices at a convenient time. Large companies with millions of users are clear examples of the best use case for microservices as they must provide uptime and scalability that the added modularity can provide.

That’s all for the monolithic and microservice architectures, I hope you enjoyed it. Please feel free to leave comments and share the article with others.

PhDc, Senior Software Engineer