A Well-Architected Monoliths
The story of the monolith application or architecture begins with the rise of the web in the late 1990s and early 2000s. During this time, most web applications were developed as monoliths, which means that all the code and functionality were bundled together in a single application.
This approach made it easier to develop and deploy applications, as everything was in one place. However, as applications grew in size and complexity, this monolithic approach began to cause the following problems.
- Harder to make changes, deploy new features and maintain the application
- Slow Deployment, for any small change, the entire application needs to be deployed
- You can’t scale one or more modules/components of an application independently, however, one has to scale the entire application
- Slow Time-to-market, as being a monolith application feature delivery may take more time
- Difficult for large and geographically distributed teams to work together
Despite having those issues, there are several reasons why a developer or organization might choose a monolithic architecture as their first preference:
- Simple to develop, test and deploy
- Cost-effective, better performance(because of low network latency) and easy to secure
- Easy to learn and understand as its technology and platform-specific
- Easy to debug and troubleshoot, making developers' life easy :)
Furthermore, there are certain best practices and tweaks that you can apply to your monolithic application to make it more modular, scalable, and flexible to a great extent. By doing so, you can overcome its limitations and reap the benefits of a monolithic architecture.
Define Logical Boundaries
Let’s start with the services first. In this approach, you will define the logical boundaries for your services and group them.
Over a period of time, a usual monolith design starts introducing lots of interdependencies and tight coupling and impacts the application’s reliability and flexibility.
To address this issue, one potential solution is to group services together based on their respective business domain or use cases, creating a logical boundary around each group. This can be achieved by implementing techniques like domain-driven design and separation of concerns. Nonetheless, it is essential to keep your services within a single physical boundary and establish communication through a single process.
Isolate the Data used by Service(s)
Likewise, when it comes to databases, it’s recommended to assign each service or group of services their own schema within the same database. By doing this, you create multiple logical boundaries to isolate the data used by service(s) within a single physical boundary.
Hybrid Approach
By defining the logical boundaries for your service(s) and data it becomes easy for you to decouple the service(s), workflows, and processes that operate asynchronously and require frequent scalability.
In this approach, the application is still structured as a monolith, but one or more service(s) or processes within the monolith are built as independent microservices or serverless compute units i.e. Functions, Webjobs and LogicApps etc.
This approach combines the benefits of monolithic, microservices and serverless architectures, and provides enhanced flexibility and scalability, without the added complexity and operational overhead of a fully distributed microservices architecture.
Additionally, it can make the transition from a monolith to microservices more manageable by allowing teams to gradually decompose the monolith into smaller, independent modules over time.
Takeaway
Overall, by applying these best practices and tweaks, you can make your monolithic application more modular, scalable, and flexible, and overcome its limitations. However, it is important to note that these changes require careful planning and implementation to ensure that they do not introduce new issues or complexities.
Based on my domain knowledge and several years of technical experience, these are my views. However, I would appreciate hearing your thoughts and recommendations.