Kubernetes vs Docker

Kubernetes vs Docker: What are the Differences?

Two different terms Docker and Kubernetes play vital roles in the container ecosystem for application development, deployment, and installation. These terms serve different purposes but their architecture and work are quite different from each other. Docker is a container runtime that containerizes the application while Kubernetes is a container orchestration system that works with multiple container runtimes including Docker.

What is Docker

Docker is a well-liked container runtime that is utilized to build, execute, and ship software, applications, and programs in lightweight containers. Docker plays with different components to manage containerized applications such as Docker Daemon, Docker client, Registry, Containers, and Images.

Docker Daemon and Docker Client

Docker Daemon is considered a Docker host that manages and runs the containers and images. The 

The Docker client is utilized to give commands to the Docker daemon on how to manage and deploy the application. For this purpose, Docker Daemon uses Rest API to interact with the Docker client.

Docker Registry

The Docker Registry is another important element that is used to manage the Docker images. Docker provides an official Docker Hub registry from which users can get hundreds of official Docker images and users can also publish their images on the Docker registry. However, users can create their own private registry as well.

Docker Container

Containers are another essential element of Docker. It is referred to as a small executable isolated package that builds, deploys, and manages the applications along with necessary dependencies. It provides an isolated environment that provides an extra layer of security to containerized applications. These containers are replacements for the virtual machines as these use the system resources and OS virtualization.

Docker Images

Images in Docker are considered as building blocks of Docker. These are utilized to create, instruct, and manage the containers. Docker images are also referred to as snapshots or templates of containers that contain simple textual instructions and guide the containers on how to execute and manage the containerized application:

Docker Architecture

Now, we have understood the Docker components, moving forward let’s understand the architecture and workings of Docker.

How Docker Works With Docker Components

Docker Client offers a vast command line utility that is used to give commands to Docker Daemon. To build, deploy, or install the application, the user gives commands to Docker Daemon through the Docker client. The Docker Daemon reads these commands and acts accordingly. 

Docker Daemon can interact with the Docker registry to get or download the image to create the container. Downloaded or user-created images along with containers are managed in Docker Host through Docker Daemon. Docker Container uses OS virtualization instead of virtual machines that run their own OS and kernel.

Features of Docker

Here are some characteristics of Docker:

Isolation

Docker provides an extra layer of security through isolation. It not only protects the containerized application from other containers but also from the underlying system.

Cost Effective

First, docker uses system resources directly and does not need extra resources like virtual machines. This will save the system resources. Secondly, docker can deploy the image in seconds which increases the performance and processing speed.

Portability

Containers are portable by nature and can be easily installed and executed on another system that contains a Docker setup. These containers encapsulate the program and dependencies in a small package, therefore it can save the user application from dependency errors and can be easily shipped or delivered to any other system.

High Performance

Dockerize applications give high performance as these are coupled with required dependencies and packages. So, the chance of error occurrence is minimal.

Scalability

Docker allows the user to scale up or scale down the application according to user needs by offering horizontal scaling of Docker containers.

What is Kubernetes

Kubernetes is another famous container deployment environment in the container ecosystem. The Kubernetes is also known as a container orchestration system that is utilized to automate operational tasks such as application and software deployment, management, and scaling. It is a step higher than Docker which runs multiple containers in a single pod and usually, it is used to manage and deploy containerized applications and software.

Kubernetes can work with different container runtimes and Docker is one of them. Kubernetes’ major components are the Kubernetes cluster, Master node (Control Plane), Slave nodes, and Pods.

Kubernetes Cluster

Kubernetes cluster runs the nodes inside the cluster that execute the containerized applications. Usually, nodes are of two types: Master node and Worker node. Every cluster at least must have one worker node.

Master Node (Control Plane)

The master node is also known as the managerial node or Control plane. It is used to manage the containerized application in the worker node. It is responsible for making decisions such as node scheduling, exposing APIs, scaling applications, and many more. Control Plane container kube scheduler, Kube controller, API server, and etcd.

The Kube scheduler is used to monitor and schedule the node of the new or orphan pod. Kubernetes controllers are of two types: cloud controllers and kube controllers. These are used to execute the kube controller process and align or match the desired and current state process or object inside the node either on the cloud or on the local Kubernetes cluster. The API server is used to manage and expose rest APIs and etcd is a storage of Control plane that stores the cluster data, state, and configurations.

Slave Node (Worker Node)

Slave nodes are responsible for managing and deploying the containerized applications inside the pod. Worker nodes are controlled and operated through the Master node. It contains a kube proxy to manage the network rules inside the node and enable communication between the network and the pod. The Kubelet in the slave node is responsible for communicating with the control plane node and managing the pods accordingly.

Pods

Pods are smaller units of the Kubernetes cluster. It is purely responsible for running multiple containers and also managing the share volume that is attached to the containerized application:

Docker Architecture

Let’s understand the workings of the Kubernetes cluster. 

How Kubernetes Works with Kubernetes Components

Kubernetes CLI (kubectl) is a client tool that is used to interact with the Kubernetes cluster. First, kubectl communicated with the control plane to create and schedule the containerized application inside the pod. The kube scheduler schedules the new container or pod on the worker node. The Kube controller manages and monitors the executing pod and is responsible for matching the desired and actual state of the pod. It communicated with the kubelet in the worker node and the kubelet deployed the pod accordingly inside the worker node. This communication is done through the control plane API server.

Features of Kubernetes

Here are some features of the Kubernetes Cluster:

Task Automation

Kubernetes is known for Task automation that automates containerized application monitoring, scaling, and management. 

Flexibility

Kubernetes offers a flexible environment by automatic scaling, operates multiple environments, and offers and works with various cloud services.

Isolation

Using role binding, roles, and cluster roles, Kubernetes can isolate the cluster.

Auto Healing

Kubernetes offers an auto-healing mechanism through Kubernetes deployment.

Scaling

It also offers horizontal and vertical scaling of the application.

Multi Container Service

A single pod can run multiple containers and each node can execute different pods.

Cloud Capabilities

It offers and can work with single and multiple cloud services to manage the Kubernetes cluster on a cloud host.

With the foundational knowledge of Kubernetes and Docker, let’s understand the key difference between these terms through the below sections.

Kubernetes Vs Docker

Docker is a simple container runtime tool that is used to containerize applications. Docker deploys the applications by deploying the containers. Docker can handle multiple containers on Docker Daemon and run multiple containers at once through plugins such as Docker Compose.

In contrast, Kubernetes is a container orchestration system that works with container runtime tools like Docker. The Kubernetes can execute and manage multiple containers in a single Pod of the Kubernetes cluster and each cluster node can run multiple pods. Rolling back changes and container monitoring in Docker is done manually and it’s a quite difficult task. But Kubernetes is used to automate such operation tasks and easily roll out the changes and monitor the application or container inside the pod.

The major difference between Kubernetes and Docker is in their architecture and working as explained in deep detail in the above sections. Kubernetes has quite a complex structure and can be used to deploy and isolate the application on a larger scale. However, Docker can be used for local development or deployment.

Let’s check the Key difference between Kubernetes and Docker in tabular form:

Kubernetes Docker
Kubernetes is a container orchestration system and can work with container runtime (Docker)Docker is a simple container runtime tool.
Kubernetes architecture and workflow are quite complexDocker is simpler, portable, and easy to use.
Kubernetes offers auto-scaling and healing mechanisms through Kubernetes deploymentDocker can scale the containerized application but does not provide auto-scaling and healing mechanisms.
Kubernetes runs a cluster that operates multiple worker nodes and control planeDocker runs on a single node.
Kubernetes can roll out and roll in the deploymentDocker cannot roll out the changes automatically.
Kubernetes can run and use built-in monitoring Docker needs a third-party tool for monitoring

Docker can achieve and manage multi-container environments through a third-party tool, Docker Swarm. Let’s check out the difference between Docker Swarm vs Kubernetes in the below section.

Docker Swarm VS Kubernetes

Docker itself is unable to run a multi-container environment. However, Docker can work with Docker Swarm to execute multiple container architecture. Docker Swarm is a container orchestration system that is utilized to cluster, manage, and schedule containers. Docker Swarm cannot work with Kubernetes and is not similar to Kubernetes. It is simpler and has limited properties to manage and run the container orchestration. Here are some key differences between Docker Swarm and Kubernetes:

Kubernetes Docker Swarm
Kubernetes is a complex orchestration system and is difficult to installDocker Swarm is a simpler container orchestration and is easy to install.
Kubernetes is more powerful but steep learning curveDocker Swarm has limited functionality and is easy to learn.
It is the best choice for extremely large-scale deployment.Docker Swarm can work well for local and smaller deployments.
It supports an auto-scaling mechanism Docker Swarm is required to scale the deployment manually.
Requires Separate CLI tool (kubectl)Can work with Docker CLI

Benefits of Using Docker With Kubernetes

Using Docker and Kubernetes together is beneficial in that way the container in Docker will be used to isolate the application with dependencies and Kubernetes will deploy and cluster your containers. Using Kubernetes with Docker makes it simple to make changes in containerized applications and users can also easily monitor the application without using any third-party utility or tool. Working with Kubernetes and Docker will improve agility by making it easier to update the application and execute new features:

Docker VS Kubernetes, Which one is Right For You?

Docker is used to deploy and manage the application in containers for local development on a small scale. However, Kubernetes is a container orchestration system that is more complex and powerful than Docker and is used for extremely larger-scale software and applications. Kubernetes itself can work with multiple container runtimes. So, in order to operate the smaller application, Docker is the best choice and by enabling Docker Swarm, the user can run a container orchestration environment. However, in order to manage the application for larger organizations on a wider scale, Kubernetes is more flexible and powerful.

Conclusion

The key difference between Docker and Kubernetes is Docker is a simple container runtime and containerized the software and application on a smaller scale. In contrast, Kubernetes is a complex container orchestration system that clusters the containers and can work with multiple container runtimes including Docker. Both have quite different architecture and use cases. Users can choose between Docker and Kubernetes according to their needs and market demand. We have covered the Kubernetes and Docker architecture and the key differences between them.

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