Docker vs Kubernetes: let’s see how they differ and why it sometimes gets a little confusing

We often hear people asking if it’s better to use Docker or Kubernetes, as if you had to choose one or the other. But that’s like comparing apples and oranges. If you’ve asked yourself this too, don’t worry – it’s a very common misunderstanding.

Kubernetes and Docker are basically two different technologies and tools, with equally different uses. Docker and Kubernetes can be used together to build and deploy applications at scale. But let’s see in more detail what they are and what they are for.

What is Docker?

Docker is a tool used to run containers: Containers are similar to virtual machines, in that they simulate a machine running inside your actual computer.

The idea of isolating environments isn’t new and there are other types of container software, but Docker has grown in recent years and become a standard. 

Docker uses the Docker Engine, which is a runtime environment that allows you to create and run containers on any development machine. It stores or shares the container images through a registry (Docker Repository) such as Docker Hub.

What is Kubernetes?

Kubernetes is open-source container-orchestration software that provides an API to control how and where Docker containers will run.

Kubernetes allows you to run Docker containers and their related workloads and helps address some of the operational complexities that arise when there is a need to scale multiple containers, even across multiple servers. 

With Kubernetes it is possible to schedule the launch of containers based on the workload, a specific event, or other factors. Kubernetes also allows you to manage on which machines (virtual or not) the containers are to be run.

What is the difference between Docker and Kubernetes?

As we have said above, this is an invalid comparison. A more apt comparison can be made between Kubernetes and Docker Swarm (https://docs.docker.com/engine/swarm/), for example. Swarm is Docker’s orchestration technology that allows you to orchestrate containers using Docker’s native API.

An important difference between Docker Swarm and Kubernetes is that Kubernetes is meant to run on a cluster while Swarm is designed to run on a single host. Kubernetes is much more complex and provides more functionality than Docker Swarm, and can efficiently coordinate large-scale production clusters.

In conclusion

In this article we have tried to clarify the difference between Docker and Kubernetes, two tools that are often erroneously compared. Docker and Kubernetes can work together and have different, but very complementary, purposes.

If we want to find a difference, we can say that Kubernetes has a much higher level of complexity and a steeper learning curve compared to Docker. If you are not familiar with these technologies, we recommend that you begin to familiarise yourself with Docker, and then learn how to orchestrate containers with Kubernetes.

For an advanced level developer, a knowledge of Kubernetes remains an important milestone in expanding their skill base. On our blog we will soon clarify a whole series of points on the topic of Devops that will contribute significantly to the skills of the modern developer.