With so many businesses going on about DevOps and what it can accomplish, it can be easy to forget just how expansive the methodology actually is. Several potential tools and tasks can go into a successful DevOps pipeline, to the point that very few DevOps cultures are exactly identical.
That being said, there are certainly common elements to DevOps, one of the most important of which is ‘Continuous Deployability’. The modern marketplace demands regular updates even from non-customer-facing services, with many companies releasing several batches of code per day. Without continuous deployability, services will typically lose their competitive edge.
Despite advances like infrastructure as code and cloud storage making delivery targets more achievable, many businesses still struggle. One of the most common reasons is that, despite utilizing DevOps, the organization’s services are not structured in a way that supports the priorities of its coders.
One of the most common questions that pops up when considering application structure is whether to go with a ‘monolithic architecture’ or ‘microservices’. The DevOps methodology can work with either, but both choices certainly have their share of pros and cons.
What is a monolithic architecture?
Monolithic architectures have been around for longer and are built to last. Their characteristics include:
- All code is stored in one place
- Even individual updates often require changes to the wider code base
- They are extremely secure
- Applications share data and will often perform better as a result
- All functions are served in one place
What is a microservice?
When we talk about ‘microservices’, we are referring to architectures that operate as a collection of services:
- Each service is organized around business capabilities
- Services are deployed, managed, tested, and maintained individually
- Application processes are carried out as separate services
- Microservices are usually managed by smaller teams
- Microservices enable frequent, reliable, and rapid delivery
- Services can be scaled and updated separately and will typically evolve over time
- Results are delivered iteratively
- Separate modules communicate with each other through Application Programming Interfaces (APIs)
Monolithic architectures vs Microservices
In terms of modern IT, microservices may seem like the obvious choice. While they are typically more complicated in terms of structure, they are also easier to manage and update, which appears to suit the current market to a tee.
However, microservices are not always the best choice. In some cases, monolithic architectures offer a sturdier and simpler approach perfectly suited to getting the job done. It is also worth remembering that not all architectures require a modular approach, even if frequent testing, changes, and deployment are necessary.
The answer to which architecture type is better will often come down to the size and complexity of the application or business in question. Will continuous evolution be required during the development process and beyond? How large will the team managing the application be?
The best approach will always be to consult an experienced DevOps engineer. However, there are certainly a number of pros and cons to keep in mind.
Pros and cons of monolithic architectures:
- Testing and debugging – Lacking the complexity of microservices, monolithic architectures are easier to test and debug. This is especially true for end-to-end testing
- Easy development – Using monolithic architectures as standard is simple, giving development teams a much easier time building applications
- Simple to deploy – With monolithic applications, only one directory or file usually needs to be deployed. This can be a huge boon for smaller development teams
- Simplified organization – Worrying about handling, caching, performance monitoring, logging, and other cross-cutting concerns can cause major disruptions in development. Monolithic applications only focus on the functionality of a single application, making them far easier to manage
- Hard to scale – Coders must scale the entire application rather than being able to focus on individual components
- No future proofing – To integrate new technology into a monolithic architecture, the entire thing will usually need to be rewritten from scratch
- Hard to make changes – Monolithic architectures are complex and tightly organized in a way that makes any changes likely to affect the entire system. This can make it difficult to make any fixes or improvements without creating a huge workload that must be tightly organized across the development team
- Clarity – Monolithic architectures can easily become too complicated to understand once they start to scale up. As the code becomes more complex, it will also get more difficult to manage
Pros and cons of microservice architectures
- Clarity – With a simple modular structure, microservices are far easier to manage and understand. Most importantly, coders can focus on individual services which are relevant to the business goals they are currently focusing on
- Ongoing improvements – Individual services within a microservice architecture can be improved separately without impacting the rest of the application. This makes microservice architectures far easier to manage for businesses that release updates regularly
- More scalable – Because each piece of a microservice can be managed independently, they can be scaled up and improved without having to make expensive alterations to the whole application. This is far more efficient and cost-effective than having to alter an entire monolithic architecture
- Less harmful bugs – Because each element of a microservice is separate from the rest, any issues with a specific service will not affect the rest of the application. Coders also have greater clarity over which aspect of the architecture is experiencing problems, making bugs easier, faster, and cheaper to fix
- Evolution – Microservices are not stuck rooted in the technology that was originally used to enable them. Instead, coders are free to adopt and integrate new frameworks or technologies for individual elements in their microservice
- More difficult testing – The modular structure of a microservice can make it more difficult to test the architecture as a whole
- Careful structuring – While it sounds good on paper to have every element of a service functioning independently, is does mean that the connections between databases, modules, and so on have to be managed carefully
- Cross-cutting – Any cross-cutting can create headaches for your development team. If you choose a microservice structure, your coders will have to deal with logging, health checks, metrics, externalized configuration, and so on
- Complex deployment – When the different elements of an application are managed separately, the services in question must also be deployed independently
Should I choose monolithic architectures or microservices?
As we mentioned previously, the choice of whether a monolithic or microservice approach will best suit you will inevitably depend on what your situation is and what you want to accomplish.
A monolithic architecture is best for simple services managed by tiny teams. Size creates complexity, and when your system only needs to facilitate simple business goals and requirements, the agility of a microservice may be irrelevant. It is also worth mentioning that, despite the title, ‘monolithic’ architectures can usually be developed efficiently and painlessly when an application needs to be launched as quickly as possible. Finally, while microservices offer more than their share of benefits, attempting to create and manage one without the necessary expertise will quickly lead to frustration.
A microservice will typically be the better choice when an application not only needs to serve a variety of purposes, but will also need to scale and evolve in the future. With the right management and DevOps expertise, along with the relevant engineering skills, a microservice will be easier to scale, repair, and improve as part of a continuous process.