With the flow of time, monolithic enterprise software can become quite difficult and inefficient to use. However, the development of a new product from scratch can’t be considered as the only possible variant. Though each case is individual and requires deep preliminary research, based on our experience, we can say that legacy software modernization can become the best choice for many businesses.
Migration of a monolithic architecture to microservices is a rather popular way to ensure better flexibility and scalability of enterprise software. In this article, we will describe the benefits of microservice migration and explain what types of migration strategies exist today.
Issues with monolithic products
- It is difficult to update code in parts due to the high dependency of some areas.
- The scaling of the software is rather problematic because of the close data interrelationship.
- There are serious limitations in access, updates, and other operations with data.
- The reuse of code is quite limited.
- It can happen so that there won’t be a single developer who will be able to understand the entire architecture and code of an app. Though it is a common situation with any legacy software, in the case of heavy monolithic apps, it can become a serious problem.
- If there are several teams of developers involved in the project, it can be difficult to organize their work efficiently.
- When some functionality is changed, at the testing stage, it is crucial to check not only the updated feature but also all the functionality that is related to it at least indirectly.
Microservices: why use them?
The microservices architecture ensures greater flexibility which is extremely important when we are speaking about huge enterprise software. This approach to development presupposes building a collection of small services that together form a single system. Each microservice has its own data storage which means that all data of each microservice is placed in the individual storage.
Thanks to the fact that the deployment of each microservice takes place without any dependence on the deployment of others, it is possible to update and scale apps faster and easier. Different microservices can be the responsibility of different development teams focused on specific app functionality. Teams can work autonomously.
If something goes wrong with a particular microservice and it fails, developers can isolate the failure to one microservice only. As a result, it will help to avoid cascading failures and the total crash of the software. One service can be broken but the critical app can continue running.
Usually, apps with the microservices architecture have a significantly smaller codebase in comparison to monolithic software. It makes it simpler for developers to understand the code even when it was written by other experts. As a result, the maintenance of such apps is also much easier.
The use of microservices helps to overcome the dependency from a single programming language or technology as microservices written in different services and with different technologies can work together.
When the entire software logic is migrated to microservices, there is no strict addiction to the programming language for the frontend part. It allows using the same microservices across various platforms.
There is a possibility to use different Database Management Systems (DBMS) for each microservice which can provide benefits for each particular case.
Moreover, developers can build highly loaded systems and place microservices on different servers.
Migration to microservices: what for?
The reason for refactoring a monolith to microservices is simple. A microservices-based architecture allows solving many problems of monolithic software that can lead to technical debt. If you have obsolete legacy software, designing microservices architecture will be a more efficient approach to modernization than updating a monolithic app or building a new product from scratch.
However, the possibility to reduce technical debt is not the only benefit of microservice migration. There are also some other factors that make businesses consider microservice best practices and think about implementing them in relation to their enterprise software. The list of these factors includes the following ones:
- Improved efficiency. With microservices, developers can use the underlying infrastructure and the code significantly more efficiently. As the amount of infrastructure needed for running a certain app is smaller than for monolithic software, development costs can be reduced by up to 50%.
- Better agility. As the entire functionality is broken down to the basic level and then related to some particular services, it’s possible to update and change only the relevant parts of an app. Microservices help to streamline the development process and help to minimize time to market.
- Great resilience to failures. As we’ve already mentioned, the failure of one service, if treated properly, won’t cause the entire failure of the app.
- Increased revenue. Microservices-based software products stand out from the crowd for their good performance and less downtime. All this helps to ensure better user experience and retention, which, in turn, contribute to revenue growth.
How to migrate a monolithic app to the microservices-based architecture
The general migration process can include the following steps:
- Identification of logical components.
- Components refactoring.
- Identification of component dependencies and groups.
- Remote user interface API creation. This remote API is intended for organizing communication between the software itself, its components, and its users.
- Migration of component groups to macroservices (to do that it is necessary to move the selected groups to separate projects and to conduct their separate deployments).
- Migration of macroservices to microservices.
It is recommended to start working with the microservices that are less dependent on the monolith itself. Such an approach will allow you to minimize changes introduced to your monolithic app from the very beginning.
Before approving a migration strategy, each case requires deep research and analysis. However, we can define a couple of the most popular ones.
Strategy 1: Strangler Pattern
One of the most widely applied monoliths to microservices migration patterns is the Strangler Pattern. It includes three main steps:
- Transform: New components are developed independently. As migration to microservices can be combined with migration to the cloud, components can be built already in a new environment.
- Co-Exist: Old and new components exist together.
- Eliminate: Old components have to be deleted from the monolith.
Strategy 2: Domain-Driven Design
This principle presupposes building software for ever-changing business requirements in full accordance with the specificity of the domain for which an app is being created.
The DDD migration approach is split into the following steps:
- Cease expanding the functionality of the monolithic app
- Separate the frontend part from the backend
- Decompose the monolithic application into microservice
The correctly chosen microservices migration strategy helps businesses to make their obsolete monolithic apps meet the modern digital standards and industry requirements.
However, please bear in mind that you shouldn’t view microservice migration as the universal solution for those who have large enterprise software. The best way to find the most appropriate approach is to have a consultation with professionals.
Our specialists have strong expertise in different types of modernization services like Delphi migration, software re-engineering, and enhancement, among others.