Challenges Before The Advent Of Microservices

Before the familiarity of Microservices in the market, Monolithic architecture played a predominant role. Monolithic architecture is like a big container wherein all the software components of an application are assembled together and tightly packed. It functioned as a tightly coupled software where each component along with its associated component must be present in order to execute or compile the code. Here, a server side application which executes a domain specific logic will retrieve an update data from the database and at the same time populate the HTML views to be sent to the browser.
Suppose you have an application where the client browser has customer service, cart service and product services which when deployed forms a single monolithic application. This application is easy to deploy, launch and simple to scale. But there is a glitch in the comfort zone of monolithic architecture

The Right Time to Quit Monolithic Architecture

Slow Development - The large and complex applications developed as a result of monolithic architecture slows down the development due to modularity breaches which can be difficult to understand on how to correctly implement a change and hence the quality of code declines over time. Strenuous update - As the application grows, the application becomes difficult to understand and modify because multiple teams are working on it and the codebase is entirely large. Now suppose if I have to update card services, then I will have to redeploy the application including customer service and product service. This increases the risk associated with redeployment and discourages frequent updates

Unscalable- Each copy of the application instance will get access to all data making caching less effective thereby increasing memory consumption. The application thus developed is less scalable because different app components have different requirements. For example- One component might be CPU intensive and other memory intensive

Unreliable and Inflexible - The tightly coupled component makes it unreliable because if one goes down, the entire system will fail to run. Monolithic architecture makes it difficult for an application to adopt new frameworks and languages.

Why Microservice?

Microservices is an architecture style that structures an application as a collection of small autonomous services, modelled around a business domain. Earlier all the components were in the same module but now in microservices all the components being in different modules communicate with each other using a well defined interface usually rest or messaging. The self contained process avails different and unique capabilities and multiple services are possible by communication through APIs. Each microservices will focus on one single business capability which leads to better quality and throw. The data is federated because all the components have their own instances, own data model and own data.

Microservices to Enhance Application

In microservice, services are small, independent and loosely coupled because each service has a separate code base managed by a small development team and can be deployed independently. Hence the team can update the existing services without rebuilding an entire application. internal implementations of each service are hidden from each other since they do not share the same framework or library or technology. The management components are responsible for placing services on nodes,identifying failures,and rebalancing services across nodes.
Service discovery component maintains the list of services and which nodes they are located in. The API gateway acts as an entry point for clients where API gateway forwards the call to the appropriate services on the backend and aggregate the results from various services and return the aggregate response.