Microservices Architectures - Non Functional Requirements - Scalability


In this article, we explore the important non functional requirement called Scalability.

What you will learn

  • What Is Scalability?
  • Why is Scalability important?
  • What are the different types of Scalability?
  • What are the best practices in building Scalable systems?

Non Functional Requirements and Microservices

This is the part of a series of articles on Non Functional Requirements:

What Is Scalabiity?

Let’s say we have an application A, that supports N number of users with its current infrastructure.

If we increase the infrastructure by a factor of 10, can we hope to support 10 times the current users?

This is at the heart of scalability.

How we can we support a multifold increase in number of users with a linear increase in infrastructure?

The question that naturally follows is

  • How do you build scalable applications?

For that, we need to understand the types of scalability.

Types Of Scalability

At a high level, there are two kinds of scalability:

  • Vertical
  • Horizontal

What Is Vertical Scalability?

Vertical scalability is all about increasing the hardware and processing capacity available to a system.

Consider the following microservice architecture:

image info

Suppose Microservice1 is deployed on a specific system. Vertical scaling for Microservice1 system would be achieved by increasing the CPU processing power, or by augmenting the amount of main memory on the physical server.

Vertical scalability has limits - Its very expensive to purchase powerful hardware. Vertical Scalability can only help you to a certain extent.

What Is Horizontal Scalability?

How about having 5 instances of Microservice1 instead of just 1 instance? How about having 5 Naming Servers and 2 API Gateways? This is the core thought process for Horizontal Scalability.

Most of the times that we talk of scalability, we refer to horizontal scalability.

Discussing horizontal scalability brings us to a very important question: “How do you build scalable applications?”

Building Scalable Applications

Let’s look at few of the important factors to consider when building an application which can scale.

Have Modular Applications

A very important factor in scalable applications is modularity of your applications. In our example microservice architecture, there are multiple modules or components, each of which can be independently deployed. For example, you can increase the number of instances of each of the microservices, independently.

If you have large monolith applications, or large monolith databases with huge amounts of data within them, they become huge bottlenecks. For example, it is very hard to replicate large databases, or to scale them, vertically or horizontally. Same is the case with monolith applications.

An important step in improving scalability is to make the application more modular, by adopting a microservice architecture, for example.

Improve Caching

If part of the system has higher load, and we access certain data very frequently, caching is a viable option to improve scalability.

Enterprise web applications generally have a lot of data available that can be cached. Microservice3 from our example above might be returning the list of all states for a particular user request. To improve efficiency for future requests, Microservice1 can cache this result, once a day. That can potentially reduce the load on Microservice3.

Another option would be to have a built-in cache for each of the microservices. For example, Microservice1 need not connect to a database to get results for a query; it can use an internal cache.

A distributed cache caching data across different instances of a microservice might also be an option.

Do check out our video on this:

image info

Summary

In this article, we introduced you to the concept of scalability. Scalability addresses the aspect of addressing increased load with minimal increase in system infrastructure.

We saw that there are two main kinds of scalability: vertical and horizontal.

Scalalbility of an application can be improved by designing it in a more modular manner. Different kinds of caches can also help with Scalability.

10 Step Reference Courses

Image Image Image Image Image

in28Minutes is helping 300,000 Learners across the world reach their learning goals. Click here for the complete catalogue of 30 Courses.

Related Posts

Spring Boot Tutorials for Beginners

At in28Minutes, we are creating a number of tutorials with videos, articles & courses on Spring Boot for Beginners and Experienced Developers. This resources will help you learn and gain expertise at Spring Boot.

Spring and Spring Boot Video Tutorials for Beginners

At in28Minutes, we are creating a number of tutorials with videos, articles & courses on Spring Boot for Beginners and Experienced Developers. Here's a list of video tutorials and courses for you

Software Design - Separation Of Concerns - with examples

Software architects and programmers love having Seperation of Concerns. What is it? Why is it important? Let's get started.

Object Oriented Software Design - Solid Principles - with examples

Software design is typically complex. Object oriented design takes it to the next level. There are a number of design patterns and other stuff to be aware of. Can we make things simple? What are the goals to aim for when you are doing object oriented design? SOLID Principles is a great starting point for Object Oriented Design.

Software Design - Open Closed Principle - with examples

Open Closed Principle is one of the SOLID Principles. You want your code to be easily extended. How do you achieve it with minimum fuss? Let's get started.

Software Design - What is Dependency Inversion Principle?

Dependency Inversion Principle is one of the important SOLID Principles. Dependency Inversion Principle is implemented by one of the most popular Java frameworks - Spring. What is it all about? How does it help you design good applications?

Introduction to Four Principles Of Simple Design

With agile and extreme programming, the focus is on keeping your design simple. How do you keep your design simple? How do you decide whether your code is good enough?

Software Design - Single Responsibility Principle - with examples

For me, Single Responsibility Principle is the most important design principle. What is Single Responsibility Principle? How do you use it? How does it help with making your software better? Let's get started.

REST API Best Practices - With Design Examples from Java and Spring Web Services

Designing Great REST API is important to have great microservices. How do you design your REST API? What are the best practices?

Designing REST API - What is Code First Approach?

Designing Great REST API is important to have great microservices. Code First approach focuses on generating the contract from code. Is it the best possible approach?