How to Choose Between Kubernetes and Docker

DevOps is a set of practices/concepts that combines various tools to reduce the gap/problems between developers and the operations team. The goal of the DevOps is to reduce the problems faced by developers and system admins by automating code deployment from the local development server to the production server, making it easy and error free.

If you are new to DevOps or if you are learning DevOps, you are going to hear two different sets of terminologies within the DevOps community:

Docker and Kubernetes

These two tools have grown very popular in the DevOps workspace. Many people often get confused about using Docker and Kubernetes. This is because many people fail to understand when to use Docker and when to use Kubernetes.

In order to understand the cases in which to use Docker and Kubernetes, first, we need to know where the development and production teams are facing a problem and what type of problem it is. Understanding the existing problem is key to deciding whether we need Docker and Kubernetes. Second, we always think of both as competitor tools. However, this is not true. Kubernetes and Docker are different tools. This article contains a third party affiliate link.

In this article, we will cover the following topics:

1. What is Docker?
2. When do I use Docker?
3. What is Kubernetes?
4. When do I use Kubernetes?

What is Docker?

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First, we have to understand the problem areas in traditional application development. From there, we can easily understand why Docker was created and where it needs to be used.

Assume you are creating a web application on your local machine that works fine on your system. But when you try to move the project from the development machine to the testing and production server machine, you face some error — part of the application may not be working as expected in the testing or production environment.

Let us take a scenario. Imagine you are generating a PDF as part of your application development. To generate a PDF you need to install a third-party library for PDFs. You install the PDF library on your local machine to test the PDF generation. It works fine on the local development machine. However, when you move the code to the testing and production server, you fail to instruct the team or the operation team fails to install the PDF library (this often happens with developers). So you have not installed the PDF library on your testing and production server and therefore the PDF doesn’t get rendered. This becomes a big problem.

The developer will say: “It is working fine on my machine. I am not responsible for this error.”

And the operations team will say: “You must guide us to solve this problem. It was created by you, so rectify it.”

This is a frequently occurring issue and to address this problem or bridge this gap between the developers and operations team, Docker was created.

By using Docker, we can create a virtual workspace (container) and develop your application (ERP, CRM etc.) inside the Docker container. This container is packed with all your dependencies. You can easily ship/host this container to any environment (say, the testing and production server) from your local development server without any problem. So the code/app deployment problem can be automated without any error using Docker.

When do I use Docker?

Using Docker, you can move your application from a local development server to a production server without any error. Docker is highly recommended for all application development. Docker offers so many tools (software such as NodeJS, PHP, Java, Any Database, etc) as images.

So you can easily install the needed software using Docker and create a container for the application development. Databases are a great fit for Docker. You can easily move the database container from one machine to another without any problem. If you are developing a complex software application then Docker will save your life by automating the code deployment.

What is Kubernetes?

You can easily create a container and host it using Docker. Imagine you have a single NodeJS application created using the Docker container, which is running on the cloud server. Now your application is earning more views. This increases the load on the servers.

One NodeJS instance cannot handle all the load. Thus, you effortlessly deploy another instance of NodeJS by using the docker run command to handle the load. However, you now have to watch the performance and health of each container added by you manually. And you have to add more containers manually if the load increases further.

If the container fails/crashes you have to fix it manually.

You solved the deployment problem by using Docker. However, you are unable to automate fail/crash fixing of the multiple containers using Docker. And you are unable to automate addition of more containers in case the server load increases.

To solve this problem Kubernetes was created. By using Kubernetes, you can easily deploy 1000s of the container and easily manage them.

In simple terms, Kubernetes was created to handle the containers created on Docker.

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When do I use Kubernetes?

1. When you want to monitor the health and performance of multiple containers.
2. To deploy 1000s of containers in a single command.
3. To detect fails/crashes of containers and fix them.
4. To scale up and scale down the number of containers.
5. For advanced networking between containers hosted across the cluster.
6. To customize deployment of containers.
7. To support all cloud service environments: many cloud providers offer built-in Kubernetes services.
8. To upgrade all the containers in a single command.
9. To roll back container updates if something goes wrong.
10. To support a wide variety of authentication and authorization services.

Summary:

This article clearly explains the uses of Docker and Kubernetes. Docker is a container to ship/host the code/application from the local development server to any environment (testing and production server) without any error. On the other hand, Kubernetes is used to orchestrate the container by managing it. In simple terms, Kubernetes is used to handle a large volume of containers by managing and automatically monitoring the containers in a single machine or across the cluster.

So Docker and Kubernetes are not created for the same purpose. They are different tools used to ease application deployment. Docker and Kubernetes used together solve problems that come up during complex application development.

I hope this article will be helpful for you.

Thanks for reading.