Microservices vs Monolith architecture simply explained
Fast development of IT industry gives companies new challenges: end-user expectations grow higher and require quick response from companies.
If earlier it was normal to develop a product for several years, now the MVP needs to be released in a couple of months. In such conditions, the microservice architecture outperforms the monolith.
To begin with, let’s understand the difference between microservices and a monolith.
Microservice is an application consisting of independent services that can work independently, and scale freely on different servers. Microservice architecture is better organized than monolithic, since each microservice has a specific task.
The main advantage of microservices is an easy reconfiguration for various purposes. In addition, they are characterized by rapid deployment, fault tolerance, horizontal scaling, low barrier to entry and ease of management.
Imagine a smart home where all components can be controlled using the remote control: open windows, turn on the TV or even close the curtains. This is how microservice architecture works.
The second type of architecture is monolithic architecture. Monolith means that the components of a product are interconnected and interdependent, and linked in a form of a single application. If one of the components stops working, all the system will go down.
Imagine a layered chocolate cake. Each new layer makes the cake even tastier, but you cannot add a strawberry layer to the middle without changing the taste and texture of the cake. We can assume that the cake has a monolithic architecture.
Disadvantages of Monolithic Architecture
- The components are too dependent on each other. If any of the modules fails for some reason, the entire application will also crash. Just imagine that there is a web application in which there are modules, such as, authorization, payment, history, etc. And for some reason, one of them breaks down. This is just a shock for business and, consequently, for developers.
- The complexity of scaling. Scaling a monolithic application can only be accomplished by getting another similar application up. But what if scaling of only one component is required, and not the entire application. How many resources will be wasted?
- Too much code. As the application grows, so does the amount of code written, which may overload the development environment each time you need to open it. This definitely reduces developer efficiency. Also, code duplication in different application modules can be a problem, as they are often created by different developers.
- It is very difficult to switch to another programming language. Since you have to install everything in one place, this leads to the fact that switching to another programming language or switching to other technologies is a big problem. For example, you wrote an application in Java, and after a while Go was released and you got a burning desire to rewrite it, because it was cooler-better-faster. With a monolithic application, even thoughts on refactoring will cause real pain, not to mention the process itself. At the moment, there are many applications that are made this way and the number of lines of code is simply unbelievable.
- Time-consuming development. This can have a big impact on the development process and the release process. The larger the application, the more important it is for developers to be able to split the application into more working parts. Because all modules in a monolithic application are connected to each other, developers cannot work these modules independently of each other. Since developers are dependent on each other, the time for developers is increasing.
Almost every successful product comes to a state where adding new features to an existing code becomes so difficult that the cost of new functionality exceeds all possible benefits from its use. In this situation, you should think about microservices.
Microservice Architecture Advantages
The advantages of microservices look quite sufficient that they convinced enterprise developers such as Amazon, Netflix, Ebay to start using this approach. Unlike monolithic architectural applications, microservices have the following advantages:
- Isolation of components. Large applications can continue to work efficiently, even if a single module fails. And if something goes wrong, it is easier to make a rollback.
- Stack Independence. Microservice architecture eliminates the commitment of the application to one technological stack and makes it possible to build a system using different programming languages and technologies.
- Simplicity. New developers are more easily involved in the work – for this they do not need to study the entire functionality of the service, you can only work on their part.
- Scalability. Scaling microservices is much easier because in order to increase system performance, you need to expand only those services that need it.
- Releasing. You can release new versions of the application much faster, because developers from different teams do not need to wait for each other when creating a new release of the application. As a result, they can make releases in parallel and with a much smaller volume of changes, which reduces the likelihood of errors.
If you want to use microservices you should understand that this approach requires additional knowledge in such technologies like Docker for components’ isolation, Kubernetes for management and Consul for service discovery. It can be a long journey, but you don’t have to do it alone.
Hidora team can help you with migration from monolith to microservices, offering architecture advisory, mentoring and migration services of seasoned professionals in all emerging technologies.
Jean-Luc is a Junior Full-Stack Tech Engineer at Hidora with a strong IT background. He is consulting clients about DevOps and also helping Hidora’s customers to make automation deployments and migrate their environments.