In this article, we will talk about microservices and how to move to them from a monolithic architecture. We will find out how to adapt to such changes with minimal risks for your organization. In fact, we will figure out how to achieve this with advantages. Excited? Let’s jump right into it.
First, let’s discuss why you need to make such a transit. At some point, you may find yourself in a situation where adding new essential features to your existing codebase becomes difficult and time-consuming. Moreover, it turns out that the cost of the new functionality is greater than the benefits it can bring. The solution to this challenge can be microservices.
The Sigma Software team regularly helps our clients with such tasks, and we have already seen firsthand that with common sense, appropriate skills and competent planning, refactoring to microservices becomes a feasible task that can significantly simplify further development and maintenance activities.
What are microservices?
There is no clear definition for it. So let’s stick with Jonathan Johnson and Laura Shiff’s description: Microservices are a specific method of designing software systems for structuring an application as a set of loosely connected services.
Instead of a monolithic approach, each microservice component has:
- Own CPU
- Own runtime environment
- A dedicated team is working on it
This architecture means that each service can run its own unique process and communicate autonomously without relying on other microservices or the application as a whole.
This has become a trend for many organizations. Such corporate giants as Amazon, Uber and Netflix have already implemented this architecture. The idea is simple: separating massive components into multiple, deployable and self-sufficient functional entities grouped according to a specific purpose. Each element is responsible for its specific functions and communicates with other components via APIs.
Advantages
This adoption can bring many benefits to your company, including improvements in resiliency, high scalability, faster time-to-market, smooth maintenance, etc.
However, the migration process can be quite challenging, especially for organizations that manage large and complex systems with monolithic architectures. However, the good thing is that microservices can peacefully coexist with any monolithic program.
You can stretch this migration process out over time, reducing immediate costs and workload and remaining fully operational throughout the process. Moreover, you don’t necessarily need to move the entire solution to microservices. You can use a hybrid strategy, extracting only those parts that are difficult to handle within the monolith and keeping the rest of the functionality unchanged.
Why convert?
Typically monolithic architecture it includes issues such as slow delivery process, system scalability, defect detection, verification difficulties, and so on. The pieces of software are tightly combined within this architecture, so even the smallest changes affect the entire application or program and require a reset. This ends up being a lengthy and painstaking operation. The same goes for scalability. You need to scale the entire application.
Well-designed and implemented microservices help solve these problems by dividing a large application into the smallest components divided by specific domains and communicating with each other through APIs. However, to end users it looks like a single application.
Each of these services can be created, tested and modified separately. If something goes wrong — your development team will be able to fix it quickly without affecting the operation of the entire application.
In short, the advantages are as follows:
- Easier installation and maintenance
- Reduced downtime through fault isolation
- Flexibility in choosing a technological set and easier scalability
- Simplified coordination within teams
However, once you introduce such an architecture, integration becomes a challenge. This requires special attention to the design, implementation and testing part of the transition process.
Switch smart
The transition from a monolith requires careful and thoughtful planning. It is best to start by cutting out pieces of functionality from the monolith one by one, step by step. Use an iterative approach and keep those chunks small. This will reduce migration risks, and you will have better control over the entire process.
First, pull out anything that can be isolated. Only after that will the remaining functions be accessed. It can be rewritten into separate microservices from scratch or left inside the monolith. In any case, it will be easier to maintain once most of the functionality is already separated.
With this approach, a typical process would include the following steps:
Planning
Identify microservice candidates and build a backlog.
First and foremost, you need to create a backlog for microservices adoption. To do this, you need to identify candidates — the parts that should be turned into separate microservices. Then you have to prioritize them to form a queue for further transition.
Of course, the best option would be that these candidates are functional groups that can be isolated from the monolith with minimal effort. Also, it would be good if they could fix some problems that your app already has.
The most obvious candidate would be an area with some resource utilization and performance issues. Or it could be a domain area that will unblock the detaches of other microservices.
If you’re looking for a more inclusive approach to determining what can be separated from a monolith, the best strategies you can apply when moving to microservices would be:
- Dividing the application into layers
- Division of the application into domain areas
- Division of the application into modules
Iterative implementation (this set of steps is repeated for each microservice)
- Choose a refactoring strategy
- Design a microservice and change it according to CI/CD and testing process
- Set CI/CD
- Implement a microservice
Ensure you have professionals available to take care of your entire migration process.
Conclusion
The transition to microservices is undoubtedly not an easy task, although it can be simplified if done sequentially. They have advantages, but there must be excellent reasons for such a switch. It requires a lot of effort and highly qualified experts who can plan and execute the migration.
You may consider such a migration if your existing architecture has become too complex to operate and manage, and put all your efforts into strategy and design. Today, scalability and agility are the keys to success — microservices provide both. With proper planning, design and execution, investments in migration it will pay off very quickly.