What is Kubernetes? A Beginners Guide with Real-World Illustration

Overview

The word Kubernetes and the technicality involved in it look cryptic for many non-technical professionals and beginners. Having said this Kubernetes is one of the hottest technologies helping professionals to build a prospective career. So, in this blog post, I have tried to decipher this technology with a simple step-by-step guide with real-world illustrations.  

What is Kubernetes in simple words?

Explaining Kubernetes in a simple style!? Ok!! That is difficult !! but I will still try to explain Kubernetes in an easy-to-understand way.

The standard definition goes like this:

“Kubernetes is an open-source container-orchestration system for automating computer application deployment, scaling, and management.”

That is too geeky for a layperson, right? So, I will break it down and use the important part to be explained further:

Kubernetes is an open-source container-orchestration system

This sentence is of more importance and lets me explain it word by word.

1. Opensource

A piece of software whose source code is known to all. That is, the instructions or logic which is used to create this software can be seen by and reused by anyone.

2. Container-orchestrator

This is the most important concept in Kubernetes. We will discuss later what a container is but as per the definition we can easily say that Kubernetes orchestrates or manages containers

3. System

The system refers to a group or collection of software built for a specific purpose in mind. The purpose here refers to the execution of a particular set of tasks that may/may not be interdependent on each other.

As we can see this whole story revolves around containers so let us focus our attention on containers, I will try to explain how Kubernetes fits into the scene.

What is a container in simple terms?

The standard definition of a container is as follows:

A container is a standard unit of software that packages up code and all its dependencies, so the application runs quickly and reliably from one computing environment to another. 

This is again a geeky definition, isn’t it? 

So, let us start with an analogy. Consider the example of a movie theatre. People come from all over places to watch the movie, but this theatre has a finite capacity and may or may not be filled. There is a theatre manager who comes and guides the audience to the movie show. 

But there is potential wastage of resources. As sometimes there may not be enough audience for a particular movie show and that leads to wastage of resources. And you also cannot play two movie shows at the same time to utilize capacity because you have a single screen. 

So, the theatre owner decides to partition this big theatre into multiple smaller capacity theatres with a small screen so that several movie shows can play at the same time and the venue can be used efficiently. 

But this approach also has multiple issues, first, we are again fixing capacity by fixing the size of halls, and secondly, for each movie shows, we need its separate screen. 

To overcome the same, a genius comes and gives a solution. He says let us project these movies whenever you need to, within a concert space of the right size and location, whenever an audience wants to watch it. 

Now imagine this projection tech is so good that it can create small virtual concert halls inside the big theatre. These virtual theatres are so good in isolation that audiences get a feeling of watching a performance in a separate theatre for their show. 

Also, this genius thinks that I can further use this technology with an integration software(orchestrator) and manage all the theatres and their respective audience and movie shows. 

Hence, we have solved the problem of dynamically managing the size of audiences and at the same time, we have been able to run the theatre with the most efficient capacity. 

Now coming back to some technical geeky reference again, that big movie theatre is our computer which has a finite capacity (i.e, CPU, memory, storage). We want to run multiple movies (i.e. application/programs) on this computer. Sometimes these programs have multiple dependencies which can affect each other’s execution. Also, sometimes there are not enough applications running that are using the computer’s resources efficiently which results in wastage of resources. 

So now projection technology ( i.e, Container runtime) comes into play and gives you this functionality for creating virtual theatres (i.e, Containers) to run applications on-demand, using whatever resources are required and available for the task. 

And the Genius gives you the orchestration facility (i.e, K8s or Kubernetes) for multiple theatres (i.e, Computer Nodes) managing the movie shows (i.e, applications/programs) and seat capacity (i.e, resources like CPU, RAM, and storage). 

When the movie show (i.e, application/program) ends, Kubernetes shuts down and withdraws the application from its virtual compute space (containers) and makes the resources available for other programs in the queues based on resource capacity requirements. 

Also, this orchestration mechanism is so good that it can manage movie theatres (i.,e Computers) of distinct sizes and locations so seamlessly that for the audience it appears a big cluster of movie theatres where they can watch whatever movie in whatever group size whenever they want. 

Kubernetes also help you run your application at a cluster of multiple workers compute nodes without the user worrying about how and where to run them. 

Now let me answer many questions that frequently pop up in your mind when we discuss Kubernetes. 

Kubernetes Architecture Simplified

Role of Master Node

As the name implies Master node in Kubernetes controls and manages the activities of all the worker nodes. The components of a Master Node are: 

• Kube-APIServer: All the external communications happen through API server.
• Kube-Controller-Manager: It acts as the governing body for the cluster formed 
• Etcd: It is the cluster database 
• Kube Scheduler: It delegates activities to the worker nodes based on the events occurring in the Etcd database 

Role of Worker Node: 

The worker node comprises the following elements: 

• Kubelet: This unit helps the CPU & RAM of the worker node to be recognized as part of a bigger cluster in the Kubernetes. It monitors all the communications from the Master node to the worker node.
• Container Runtime: It helps to start or stop a container from running. Third-party software like Docker performs this role
• Kube-proxy: Ensures each of the work nodes is assigned IP addresses. It helps in routing and traffic-load balancing
• Pod: The smallest element of scheduling is called Pod in Kubernetes. A pod is a wrapper put on a single container with an application code.

When should I use Kubernetes?

Here are the instances that illustrate when Kubernetes is suitable for your organization: 

• If your software development team is finding it difficult to deliver the product in time to customers, then they can use Kubernetes with Docker to speed up the Software Development Life Cycle (SDLC) 
• Your development team uses microservice architecture to develop applications then Kubernetes aptly suits your needs 
• To lower the cloud management costs by ensuring continuous availability of resources for running applications on the cloud. 

What are the benefits of Kubernetes?

Kubernetes offers many benefits important ones are: 

• Open source 

 As already explained Kubernetes is a completely open-source community-led project. It is not completely owned by any company thus orchestration or managing it is easy for all types of organizations.  

• Portability & Flexibility 

Kubernetes can virtually work on any underlying infrastructure-public cloud, private cloud, and on-premises servers seamlessly. Importantly it virtually works on any type of container run time.  

• Multi-cloud capability 

Kubernetes can work easily with workloads that are deployed on a single cloud or on multiple clouds with ease.  

• Improves Productivity time 

Software development teams that were deploying one project in a month can now deploy multiple times in a day.  

• Market Pioneer 

Kubernetes is currently the market leader of the open-source container-orchestration systems in fact it is termed as a de facto orchestration system. State of Kubernetes Security’s survey report also substantiates this claim as 88% of respondents use Kubernetes. 

Career Opportunities in Kubernetes

According to Gartner Research findings “Between October 2015 and October 2019, the share of Kubernetes jobs per million grew by 2,141% while the share of Kubernetes job searches increased to 2,125%.”  So, creating a career by earning certification in Kubernetes will help professionals to have a promising career. 

How CloudThat can help you to get Certified?

CloudThat is a pioneer in cloud computing certification training and with the record of accomplishment of empowering 4 Lakh professionals with best-in-industry certification training. We are a Microsoft Gold Partner, Authorized AWS Training Partner. Also, we are Google Cloud Partners delivering best-in-industry training for Azure, AWS, and GCP (Google Cloud Platform). We are on a mission to build a robust cloud computing ecosystem by disseminating knowledge on technological intricacies within cloud space and emerging technologies like AI/ML, DevOps & Kubernetes, IoT, and Security. Currently, we offer the following industry-aligned certification training on DevOps & Kubernetes. Explore our courses, get certified by authorized industry partners, and excel in your career, Happy Learning!

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