Moving from Monolith to Microservice? What all you need to consider

In this article, we look into the scenarios if you plan to move from a monolith application to a microservice.

What is a Monolith application?

• We can define an application as a Monolith when all the system's functionality is deployed together.

• The most basic form is one codebase and one single database. However, there are various alternatives like multiple modules — single database (modular monolith) and multiple modules — multiple databases (distributed monolith) do exist.

Major problems with Monolith architecture?

• The major problem with the monolith architecture is it will become difficult to manage as it becomes too large with time.

• We have to redeploy the entire application in case of any small change anywhere in the application

• It is very difficult to scale as the horizontal scaling becomes very costly.

• Adoption of new technology is difficult as we may have to replace/migrate the whole application.

But are there any advantages to using Monolith architecture?

• Yes. Monolith applications are not bad at all. After all, it is being used in a large number of applications worldwide.

• The simple and singular deployment topology can avoid a lot of issues associated with distributed systems.

• It is easier for developers to learn and develop monolith applications than microservice applications.

• It is easier to maintain.

Now what is a Microservice application?

• Microservice applications are independently deployable small services that work together and are modelled around a business domain.

• They communicate with each other via networks.

Key advantages of a Microservice application?

• The major benefit of a microservice is independent deployability. That means we can deploy only what is changed leaving other services intact.

• One of the other major benefits, it makes horizontal scaling easier and less costlier. We need to scale only the services that demand a high load.

• We can make the whole application technology agnostic as we can use the best-fitted technology for each service.

• This architecture gives you flexibility and even for solving problems that may arise in the future.

What problems does Microservice architecture create?

• Along with the host of benefits, they also bring a host of complexity to your system. The complexity increases with the increase in the number of services.

• Microservices applications are a kind of distributed applications, that have challenges in communicating with each other and a higher network latency.

• You require more computers, more networks, more storage, and more supporting licensed software. This all contributes to more cost in running and maintaining the applications.

• Microservice applications are less secure than monolith applications. This is because in microservice more information flows over between the services. This makes the data more vulnerable to potential attacks like man-in-the-middle attacks.
  

When move to Microservice?

• When we want to scale your applications quickly and cost-effectively.

• When we want to reduce the time to market. We can deploy individual services independently without waiting for coordinated releases.

• When we want to improve the robustness of your application. When designed and implemented properly, the impact of one service will not bring down the entire application.

• When we want to embrace new technology. We can use different and best-fitted technology on different microservices as per the need.

• Anyway, you should have a good reason to move to Microservice.

When moving become a bad idea?

• Where cost optimization is a policy and IT is seen as a cost centre rather than a profit centre.

• Where the business domain is not clear. Defining the service boundaries wrongly can be expensive.

• For new experimental projects or start-ups. If you working on a concept that requires significant change while developing, then it is a bad idea to embrace microservice at that stage.

• When you have a small or limited team size. You require more people to develop and maintain microservices. Also, it would help if you had skilled persons to handle the deployment and management of the microservices.

Alternatives to Microservice?

• Solve the performance issues in the existing monolith application, if you don’t have a valid and good reason to migrate to Microservice.

• Modularize the existing monolith application. Divide the existing application into multiple modules that are loosely coupled and highly cohesive.

• Microservice is not a solution for poor code standards, lack of automation, poor choice of development life cycle, poor process etc.

In summary, it is not advisable to move to microservice in all conditions. Choose your scenario and find out if the microservice is good for you.