Over the past few years, we’ve been talking Docker & Kubernetes and 1st topic we cover is monolithic vs microservices here’s why-
There has been a lot of change in the development & deployment since the ’80s till now. We can trace the evolution of how organizations have developed, deployed, and managed applications over three distinct phases:
- 80’s – mid 90’s: Data Centers with physical servers, running monolithic applications, developed using traditional waterfall methodologies.
- Late 90s–00s: Datacenters and hosting providers running Unix/Linux servers, the emergence of virtualization (VMWare, KVM), running n-tier applications, developed using agile methodologies.
- ~ 2010 – Now: Cloud increasingly replacing data centers and hosting, decomposition of applications into microservices, running on a container infrastructure, managed and orchestrated by Kubernetes, developers, and operations collaborating using DevOps methodologies.
In this blog, I’ve covered the difference between Monolithic vs Microservices which is an important topic in order to start your learning in Docker & Kubernetes. Microservices have actually given birth to containers.
Also check: our blog on Kubernetes The Hard Way (Learn from the scratch)
What is Monolithic?
A monolithic application is constructed as one unit which means it’s composed all in one piece. The Monolithic application describes a one-tiered software application within which different components combined into one program from a single platform. The three components are the user interface, the data access layer, and the data store.
- The user interface is the entry point of the application and is also the point of the program that a user will interact with.
- Data access layer is the layer of the program which will wrap the data stored.
- The data store is the most fundamental part of the system and is liable for storing data and retrieving it.
Check out: Kubernetes Security For Beginner – CKS
Advantages of Monolithic:
- Simple to deploy – In monolithic applications, we don’t need to handle many deployments just one file or directory.
- Easier debugging and testing – monolithic applications are much easier to debug and test. Since a monolithic app is a single indivisible unit, we can run end-to-end testing much faster.
- Performance: Components in a monolith typically share memory which is Quicker than service-to-service communications.
Read this blog about Role-Based access control. It’s the way to outline which users can do what within a Kubernetes cluster.
Disadvantages of Monolithic:
- New technology barriers – It’s extremely problematic to use new technology in a monolithic application because then the whole application must be rewritten.
- Scalability- You can’t scale components independently, only the whole application.
- Size – It becomes overlarge in size with time and becomes difficult to manage.
- Difficult to understand – For any new developer joining the project, it’s very difficult to grasp the logic of an oversized monolithic application whether or not his responsibility is related to one functionality.
What is Microservices?
The idea of microservices is to separate our application into smaller sets and interconnected services rather than building one monolithic application. Each module supports a selected business goal and uses a simple and well-defined interface to communicate with other sets of services. Each microservice has its own database. Having a database per service is crucial if you wish to learn from microservices because it ensures loose coupling.
Advantages of Microservices:
- The application starts faster, which makes developers more productive, and accelerates deployments.
- It enables us to arrange the event effort around multiple teams. Each team is responsible for one or more single service. Each team can develop, deploy, and scale their services independently of all of the opposite teams.
- Microservices allow the usage of the most appropriate technology for various services. Meaning each team building the selected service can choose their preferred programming language and framework, as they’re working independently.
- Once the organization develops and implements a microservices architecture, it’s the schematic diagram that may be reused and expanded upon for future projects and services.
- Each service is a separate object within the microservices framework which enables their independent functioning.
Disadvantages of Microservices:
- Since everything is now an independent service, we’ve to carefully handle requests traveling between our modules. In one such scenario, developers are also forced to write extra code to avoid disruption.
- Communication between services may be complex and there’s a higher chance of failure during communication between different services.
- The developer has to solve the problem, like network latency and load balancing.
- While unit testing may be easier with microservices but integration testing isn’t. The components are distributed and developers can’t test a complete system from their individual machines.
Microservices and Containers
It’s difficult to talk about microservices without also talking about containers, Docker delivers an easy way to create, share, and test container images, and has become very popular among businesses that have committed to developing software using containers.
Example of Microservices
This is an example of cab booking software. Each functional area of the application that is now implemented by its own microservice and the backend service exposes a REST API. Most services consume APIs provided by other services. These might also use asynchronous, message-based communication inter-service communication. Run multiple instances of each service behind a load balancer for throughput and availability.
Why MicroServices?
The good thing about using microservices is that development teams are ready to rapidly build new components of apps to fulfill changing business needs. In microservices, every application resides in separate containers along with the environment it needs to run. It allows it to maximize deployment velocity and application reliability. There’s no risk of interfering with the other applications. It also allows optimizing the sources micro services multiply team works on independent services.
In Microservices, we run all the applications on Containers (Docker), so the boot-up time and memory consumption of applications decrease, thus the performance of the application increases. In organizations, not one or two but multiple numbers of Containers (Docker) are running. So, to manage them, we use Kubernetes. Kubernetes comes in handy because it provides various facilities like self-healing, scalability, auto-scaling, and declarative state.
| What’s the Diff: Monolithic vs Microservices | |
| Monolithic | Microservice |
| It is built as one large system | It is built as a small independent module |
| Not easy to scale based on demand | Easy to scale based on demand. |
| It has a shared database | Each project and module have their own database |
| Large code base makes IDE slow | Each project is independent and small in size |
| Continues deployment becomes difficult | Continues deployment is possible here |
| It is extremely difficult to change technology or language or framework because everything is tightly coupled and depends on each other. | Easy to change technology or framework because every module and project is independent. |
Migrating from a Monolithic Architecture to a Microservice Ecosystem
The right approach for migrating a monolithic architecture to a microservice ecosystem is to divide the monolith processes and turn them into microservices. The result of this is a two-factor plan:
- Identification of existing monolithic elements which can get decoupled
- A validation that the new functionality can be developed as microservice
One of the main challenges that can emerge when initiating the migration from a monolithic architecture to a microservice architecture is to design and create integration between the existing system and a new microservice. A solution for this can be to add a glue code which allows them to connect later, something like an API.