Microservices architecture has become all the hype. A great many businesses seem to be creating their apps as microservices or rushing to migrate their monolithic apps. But is it always the best choice? Can monolithic apps still work?
Before answering that question, let’s consider what exactly it means. Monolithic architecture refers to a traditional unified model for designing software as a single unit. A monolithic app follows a tightly coupled design and requires that all components are compiled and deployed together.
In contrast, the microservices architecture advocates building apps as a collection of services organized around business capabilities. These loosely coupled components are maintained and deployed independently while being highly maintainable and testable.
Many teams hold to the misconception that these two approaches are mutually exclusive and that the monolithic architecture is the only way forward. However, this is not true for all apps and circumstances.
The Monolithic Architecture
It is essential to understand the advantages and disadvantages that the monolithic architecture offers over its counterpart before determining its suitability.
Advantages of The Monolithic Architecture
The Monolithic Architecture is nothing new. It has been tried and tested for many decades despite now being made almost obsolete by microservices. This familiarity makes the monolithic architecture the preferred choice for many.
Monoliths are the preferred and only choice for many startups and more established businesses due to limitations in knowledge and technology. Despite offering many benefits, microservices architecture requires that teams are familiar with concepts like agile, DevSecOps, continuous integration/continuous deployment (CI/CD), and are also proficient in cloud services.
All these requirements make microservices architecture somewhat out of reach for teams that are new and inexperienced. So they naturally opt for monolithic architecture. In addition, developers don’t need to focus on communicating between services and the problems and complexities they entailed.
Cost savings are a significant motivator for all organizations, irrespective of their size and maturity. Monoliths can offer cost savings in many ways, like requiring smaller teams, lesser architecture, and lesser effort. There is also the savings through reduced cost for communication between services, which also indirectly reduces the scope of work.
Disadvantages of The Monolithic Architecture
Many of the flaws associated with monoliths have become more apparent with the exponential growth and adoption of cloud technologies and infrastructure.
The inability to scale to the endless demand from online user bases and ever-changing business requirements have amplified this disadvantage. The primary method for scaling monolithic apps is vertical, that is by increasing hardware capacity and infrastructure. This method is no longer feasible due to the limitations of hardware and the costs involved.
Horizontal scaling involves increasing the number of monolithic app instances and enabling load balancing. These methods are nowhere as efficient as the autoscaling capabilities of its counterpart. Team scalability also suffers from the restrictions of monoliths. While it is not impossible, larger teams working on a shared codebase face significant difficulties due to conflicting changes.
One of its most critical restrictions is the complexities involved with expanding existing features and introducing new ones. This is due to the highly coupled nature of monolithic apps and that every feature is interconnected. In addition, there is also technology lock-in. Unlike service-based apps which can be expanded or migrated one component at a time, monolithic apps pose considerable restrictions to changes in technology and infrastructure as they have to be migrated as a whole.
What to consider before choosing the Monolithic Model
Here are some of the factors to consider before choosing monolithic architecture:
The capabilities of your team
Your team and its capabilities and expertise levels should be one of the main considerations when selecting an architecture. Unless your organization is clearly capable of handling the complexities of microservices, the communication between them, and the infrastructure and scaling needs it entails, monolithic architecture may be the more straightforward option.
The state of your business
Startups are often overzealous during their initial stages and tend to overestimate their expectations and scaling requirements. Many teams expect their proof of concept apps to require scaling within a short time and in particular areas. However, these estimates aren’t always realistic. Apps may take much longer to reach the market and gather a user base and may not always require scaling in the exact aspects that were initially anticipated.
If you are a more mature company and have your own data center or infrastructure, this can also be a factor in your decision. Opting for microservices-based apps can make considerable investments worthless.
The level of clarity regarding the domain
This factor is subjective and will depend a lot on the business domain you wish to capture through the app. An experienced business analyst will be essential in deciding the complexity of the domain and whether you need to consider it as multiple sub-domains. These can then be mapped to the architecture of the app.
If the domain is limited and does not require many different services, the monolithic model may be better suited.
The budget and timeline
Last, but surely not least, budgets and timelines tend to overshadow many of the other factors discussed above as they pose tangible restrictions on app development. Microservices based apps take longer to develop, require relatively larger teams, and tend to take longer to build and optimize. Longer timelines and higher resource needs directly translate to higher costs.
Budgets are not always flexible and can become restrictive, especially when it comes to exploratory domains. Monolithic apps are usually more fixed in scope and follow traditional waterfall-based development methodologies. These factors reduce the complexities and uncertainties involved with app development leading to better adherence to budgets.
There you have it. We looked at the advantages and disadvantages of the Monolithic Architecture. There is value in choosing it when the right circumstances are present, despite not being as well suited to modern cloud-powered trends.
We also looked at important factors to consider before deciding on sticking with the Monolithic Model or jumping on the Microservices band-wagon. If your team is at a relatively new stage, without much Microservices experience, and you’re building an unproven app with a limited budget, then the Monolithic Model is the way to go. Alternatively, Blue Sentry has professional services to augment your team, bringing your application to life in a microservices environment.