Docker vs Kubernetes: Key Differences & How to Use Both

DevOps offers an endless list of container management and deployment scaling platforms. However, Kubernetes and Docker together form the undisputed holy grail duo of container management and orchestration. Docker containers and Kubernetes clusters work hand in hand, and they are not competitors. However, Docker Swarm is an alternative to Kubernetes.

In this tutorial, you will learn the key differences between Docker and Kubernetes, from their core definitions to core functions. You’ll also learn how to install Minikube on Ubuntu 24.04 and use it to set up a Kubernetes cluster running in a Docker container.

#What is the difference between Docker and Kubernetes?

Although Docker and Kubernetes are often integrated to containerize and deploy applications in the cloud, they have different capabilities. Kubernetes provides extensive deployment scaling capabilities needed to orchestrate multiple containerized applications. On the other hand, Docker provides robust platforms that enable developers to build, run, and share container images.

#Prerequisites

Before starting this tutorial, make sure you have installed Kubectl and Docker on Ubuntu 24.04.

#What is Kubernetes and how does it work?

Kubernetes is an open-source platform responsible for automating application deployment, scaling, and managing containers. Kubernetes makes it easy to deploy applications on the cloud by offering features such as service discovery, automated rollouts, and rollbacks. It also provides a set of tools such as kubectl top. The kubectl top tool gives you resource metrics making it easy to track resource utilization.

Kubernetes works by creating a cluster of nodes which can be a physical or virtual machine. The nodes are controlled by a master node. Each node runs a container engine such as Docker to manage containers. The nodes are connected and can be scaled to keep up with the load whenever traffic increases or decreases. Every Pod gets assigned to a node. Pods are small executable components that encapsulate containers.

Kubernetes uses services as a mechanism for facilitating internal and external communication between components. Kubernetes also provides a set of APIs, such as the metrics API and Kubernetes API. They enable you to read and interact with the cluster. The Kubernetes API facilitates tasks such as creating new Pods, scaling the cluster, and deploying applications.

Below are four critical Kubernetes components you should know:

1. Namespace: Namespaces enable you to group specific Kubernetes resources, making it easy to apply network policies or resource limits on grouped resources. For example, you can set resource limits and requests for a specific namespace that groups production-ready components such as services and Pods.
2. Deployments: A Kubernetes deployment is a collection of objects that work together to manage an application rollout procedure. Deployments have two primary components, a ReplicaSet and a Pod. A ReplicaSet ensures that a given number of Pods are running at any given time.
3. Services: Kubernetes is widely used in the microservices architecture that divides a big application into small easy-to-deploy parts. These application parts can be in different containers and clusters. To communicate effectively, these parts use Kubernetes services. In Kubernetes, a service is a group of Pods that have the same selector. Services have a stable IP address when compared to Pods which have an ephemeral IP address.
4. Pod: A Pod is a group of containers sharing the same resources, namespaces, and file systems. Pods can be created using the kubectl apply command and viewed using the kubectl get pods command.

#What is Docker and how does it work?

With so many countless programming languages and frameworks being released every 5 years, creating a suitable environment for every framework gets tedious. The variety that comes with implementing many frameworks creates developer collaboration friction. This friction can be eliminated by containerizing applications using Docker.

Docker allows your team to collaborate and work on the same application and services even though there is a difference in:

• Operating system
• Libraries and frameworks
• Programming language

Docker achieves this by bundling and packaging all dependencies, libraries, and resources needed to run an application into a compressed and executable component called an image. Below are important components that make up the Docker architecture.

• Image: A container image is a software unit that compresses and comprises every dependency and library needed to run an application on any operating system. A container image is created using a Dockerfile. This file specifies dependencies and instructions that will be used to configure and build an image.
• Container: A Docker container is a running instance of a Docker image. It’s a lightweight and isolated execution environment that includes only what’s necessary for the application to work. Docker containers enable process isolation which limits security breach scope and attack surface.
• Docker Daemon: The Docker Daemon also known as the dockerd is responsible for all container network, storage, and image management tasks. Think of it as the core container facilitator. The Docker Daemon is responsible for pulling and deleting images. The container lifecycle is also coordinated by the Docker Daemon.
• Docker CLI: The Docker command line provides an interface that receives commands from users and sends the command to the Docker Daemon via a REST API. Every Docker command that you executed was handled and translated into API calls by the Docker CLI.
• Docker Desktop: Docker Desktop is a fully integrated platform that enables developers to build and share images on macOS, Windows, and Linux. It abstracts away the complexities of installing and managing the Docker Engine and Kubernetes. Docker Desktop provides a GUI for managing images, containers, and other resources. It also offers optional integrations such as Docker Compose and Kubernetes.
• Docker Compose: Running and managing multiple containers efficiently requires Docker Compose. A tool that enables you to manage multiple containers using one configuration file. Docker compose uses a docker-compose.yml file to configure multiple containers in a declarative manner.
• DockerHub Registries: An image registry like DockerHub enables developers to publish, share, and download private or public images. DockerHub is the main Docker registry. Every official image you need can be found on DockerHub. Users can also publish and set their images to private and accessible to select users.

#Key differences between Docker and Kubernetes.

#Core function and purpose

Docker provides a platform and tools needed to build and run containers. Unlike Kubernetes which manages containers and applications, Docker only manages containers and images. Docker operates at a container level.

Kubernetes provides a platform that facilitates container orchestration and manages an entire cluster of containers across distributed systems. Kubernetes operates at the application and cluster level.

#Community and ecosystem

Since Kubernetes and Docker are the de facto platforms in their respective functions, they have big communities and ecosystems. Docker's ecosystem is more developer-focused, whereas Kubernetes is geared towards system administrators and DevOps engineers. All of them have a lot of content creators who specialize in creating free tutorials and courses for beginner and expert levels.

Kubernetes is fully backed by the Cloud Native Computing Foundation (CNCF) that regulates and facilitates various certified Kubernetes courses. CNCF course certificates are highly recognized in the DevOps job market.

Docker has many free tools such as Docker Compose for defining multi-container applications, Docker Swarm for orchestration, and a vast repository of images on DockerHub. On the other hand, Kubernetes has an endless list of free open-source tools such as Helm charts, and security scanning tools such as Kubescape. You can browse the endless list of Kubernetes tools on the Kubetools GitHub page.

#Scaling processes and management

Docker on its own does not have extensive scaling mechanisms when compared to Kubernetes. Yes, you can add Docker Swarm to your Docker setup, but Docker Swarm is not as powerful as Kubernetes. Kubernetes offers advanced scaling features and it is easy to connect to vast CI/CD tools such as Travis CI.

Kubernetes is recognized as the king of scaling processes. It has various types of concepts used to scale Pods, clusters, and resources. Kubernetes uses four mechanisms to scale resources and Pods.

1. Horizontal Pod Autoscaling: Kubernetes adjusts the number of Pods in a deployment based on resource utilization.
2. Vertical Pod Autoscaling: Instead of increasing or decreasing the number of Pods, Kubernetes optimizes the Pod to better handle the decrease or increase in resource demand.
3. Automatic Scaling: Kubernetes can automatically scale applications up or down based on predefined metrics such as CPU usage and memory consumption.
4. Cluster Autoscaling: Kubernetes adjusts the size of the cluster by adding or removing nodes based on the overall resource demands.

#How to use Docker with Kubernetes

The simplest way to use Docker with Kubernetes is by using Minikube to create a local Kubernetes cluster. Minikube is a free tool that enables developers to create local clusters for learning and testing purposes. Minikube can set Docker as the driver, this means Minikube will create and run a Kubernetes cluster inside a Docker container.

The main benefit of using Docker and Kubernetes locally is that you can create many resources without the fear of high-cost implications. This allows you to test Kubernetes resources, such as Pods and services, before implementing them in a production environment.

Since testing resources using Minikube is cost-free, Kubernetes and Docker beginners can easily practice Kubernetes concepts such as NetworkPolicies and container management without incurring additional expenses.

#How to install Minikube on Ubuntu 24.04

Follow the steps below to install Minikube on Ubuntu 24.04:

Use the following command to update Linux packages.

sudo apt update

Execute the following command to download the Minikube binary.

curl -LO https://github.com/kubernetes/minikube/releases/latest/download/minikube-linux-amd64

Next, use the following command to install Minikube binary to the /usr/local/bin/ directory. The rm minikube-linux-amd64 command removes the binary file used to install Minikube. Removing this file clears space because it is no longer needed.

sudo install minikube-linux-amd64 /usr/local/bin/minikube && rm minikube-linux-amd64

Execute the command below to check if Minikube has been installed successfully.

minikube version

You will get the following output if Minikube has been installed on your machine.

#How to create a local Kubernetes cluster using Docker with Minikube

Once Minikube has been installed successfully, use the following command to start a Kubernetes cluster that will be facilitated in a Docker container.

minikube start --driver=docker

You will get the following similar output:

After the cluster has been created, you are all set to create and explore any Kubernetes resource.

#Conclusion

Kubernetes and Docker are complementary DevOps platforms that work in conjunction to containerize and orchestrate applications. Docker plays a big role in managing containers and distributing container images. Whereas Kubernetes plays a big role in maintaining and scaling containers.

Kubernetes and Docker are both resource-demanding platforms when it comes to resource management. Implementing reliable and efficient cloud solution providers and network mechanisms is crucial. Cloud solution providers such as Cherry Servers enable you to build Docker images and scale your self-managed Kubernetes clusters effortlessly with powerful Dedicated Servers — ideal for containerized workloads.

Running Kubernetes and Docker is always straightforward when there are no infrastructure issues. So, create a Cherry Servers account and explore cloud solutions needed to run Kubernetes and Docker efficiently.