Microservices architecture embraces small, self-containing services that developers can build, deploy and scale independently. Some proponents of microservices say that it represents the death of monolithic app architecture. However, despite the allure of microservices, the monolith architectural style is still quite alive and well.
If your application is not that complex, a monolith-first strategy might be the best option. Explore several advantages of monolith architecture that make it the better choice in certain development scenarios.
Microservices enable you to build services using heterogeneous technologies and then glue them together. While a lot of existing tooling is geared toward microservices, it's not so easy to find a simple way to monitor those services and make sure that they are up and running all the time. Tool implementation alone can get costly for organizations, and then teams must spend plenty of time figuring out how to integrate these tools, with architecture reliability hanging in the balance.
And despite the fault tolerance capabilities of microservices, it remains difficult to identify failures in microservices-based applications via manual monitoring and testing methods. This hardship is primarily due to the architecture's decoupled nature. Teams will need automated monitoring systems, which only steepens overhead costs.
This represents one of the biggest advantages of monolithic architecture. In a monolith, boundaries become distinct. Teams can decipher the services and boundaries, and then refactor and decompose their monolith to build microservices, if they choose to. However, if tracking is already a problem in your monolithic app, don't think that moving to a distributed architecture will make it better.
A simple place for testing
There are plenty of tools, such as profilers, static code analyzers and test frameworks, that make it easier to test and debug microservice-based apps. But when you're dealing with loose coupling, it can become a nightmare for you to determine exactly where in execution something went wrong.
Microservices-based applications can better handle fault isolation and tolerance, but one of the advantages of monolithic architecture is that it's easier to test things when they're all in one place.
Less confused developers
Before making a decision, organizations should make sure their teams are properly trained and prepared for the challenges that microservices architecture can come with. Your team will need members that have the right expertise to build, deploy and manage microservices-based applications.
If your team doesn't have the right skills, working with microservices architecture can easily become a nightmare. If your developers are used to a monolith, this architectural change comes with a learning curve, which could ruffle some feathers. If the change is avoidable from a business perspective, it's best to let your developers stick with what they're good at and comfortable with.
A microservice might require data owned by another microservice or may need to access the services provided by another microservice. If you don't design your microservices-based application efficiently, the services might be chatty, needing to communicate unnecessarily often.
Communication between the components in a monolith occurs within the same application. In a microservices-based application, developers have to use inter-service communication designs to enable the services to talk to each other. Additionally, developers have to consider whether a microservice is communicating with another microservice synchronously or asynchronously.
No moving parts to secure
Security is an important issue to take care of both in monolithic and microservices architectures, but each architecture has security benefits and drawbacks.
In a monolithic application, if there is a security issue in any one component of the application, the entire application becomes vulnerable. Teams can find it challenging to isolate a potential security threat because they cannot bring down the entire application to solve a security issue.
If you are using a microservices architecture, security efforts bring forth a different type of challenge. With many moving parts at play -- e.g., services, components, APIs, etc. -- the potential attack surface increases security burdens, but at least microservices allow teams to isolate a tainted component without compromising the entire app.
One of the biggest benefits of microservices architecture is the ability to take advantage of numerous heterogeneous platforms and technologies. One downside to this type of mixed platform approach is the different dependencies and versions at play.
Teams must ask themselves if they're willing to take up the demanding task of managing the different versions and dependencies of a microservices application, as opposed to a monolithic app that wouldn't have this problem.
When not to go for monolithic architecture
A monolithic application poses obstacles to managing the code base, whether it's continuous deployment or even just adding new features when needed. A monolithic application can scale only in one dimension, running multiple copies of the application as the volume of transactions increases.
Imagine working on a complex application with a team that is spread across geographical boundaries. Microservices architecture makes more sense in this situation because it is more cost effective, and you can manage and scale the application seamlessly. Unlike a monolithic application, microservices apps are not married to or revolve around the technology stack. As far as team distribution is concerned, a monolith poses challenges when teams are not located in specific functional areas.
Which is best for you?
Compare the advantages of monolithic architecture to those of microservices before you make a final decision about your approach. The best thing to do is follow this basic rule of thumb: Only begin considering microservices architecture once you are absolutely positive that you need to build a system that is too complex to build, deploy, scale and manage as a monolith.