Docker and Kubernetes are both compelling technologies, and most of the time, people are often confused about whether they should use Docker or Kubernetes. This blog will explain Docker vs Kubernetes and go over other vital concepts around Docker and Kubernetes. So let’s get started.
what is a container
Before diving into Docker vs Kubernetes, it is crucial to understand what a container is and why we need one.
The container is the standard unit of the application using which you can package up your applications, and you can quickly move the containers from one environment to another. It will behave in the same manner in all environments, whether dev, stage, or prod.
Containers images are very lightweight and contain everything needed to run an application: code, system libraries, runtime, and settings.
Many container technologies are available in the market like Java containers, Unikernels, LXD, OpenVC, Hyper-V Containers, Docker,podman, etc. Out of all, Docker is the most popular container technology.
what is a docker?
Docker is one of the most popular container technology, and almost all companies use it. What makes Docker more popular than the other docker container is the broad community support and ease of usability.
Docker is absolutely free to use, and there and so many readily used docker containers are available in the dockerhub. Docker is straightforward to set up in your system. You can follow this tutorial to set up Docker in your system.
Now you have a pretty good idea about the docker and container platform; let’s further understand another excellent service provided by Docker, the docker swarm.
what is a docker swarm?
Docker swarm is the container orchestration tool, which means it allows the user to manage multiple containers deployed across multiple host machines. When you deploy containers using Docker, and if for any reason your container gets killed, there is no way to start it automatically when that happens.
In such cases, docker swarm cones as a savior. Docker swarm will make sure the docker containers are always available. Even if the containers get killed, the docker swarm will read the current state of the application and start and spin up the new containers based on the state defined by the user.
Docker swarm provides the following advantages:
- Users can create a Docker swarm by using docker CLI.
- With docker swarm, you can define the desired state of the various services in your application
- user can easily scale up their application using docker swarm by simply passing the number of states to be run.
- Users can deploy containers in multiple hosts
- Containers can be easily scaled up and down based on the need.
- By default, TLS encryption is enabled for all nodes.
Check the official documentation if you wish to get more information about the docker swarm.
what is Kubernetes
Like the docker swarm, Kubernetes is also a container orchestration platform. Kubernetes was developed by Google and later open-sourced in the year 2014. Now Kubernetes is one of the top open-source projects used by many companies to orchestrate their production workload.
Kubernetes are also known as k8s. With Kubernetes, users can easily schedule and automate the deployments, and manage and quickly scale the application.
In Kubernetes, containers will be running inside a pod(a basic unit of Kubernetes). There can be one or more containers running inside Kubernetes.
A Kubernetes cluster includes a master node and a bunch of worker nodes. Master will be responsible for scheduling the workloads on worker nodes. Master will decide on which worker node pods will be deployed for high availability.
Below is the diagram of a Kubernetes cluster with all the components:
The popularity of Kubernetes is growing day by day because of the following features:
- Self-healing capability.
- Can be easily extendable.
- Support horizontal scaling
- Automated backup and rollouts.
- Enterprise grade orchestration plateform.
- Wide community support.
- Secret and configuration management.
- Provide batch processing feature.
- Provide multiple storage options.
Now let’s proceed further and see a few advantages and disadvantages of Docker and Kubernetes.
Advantages and disadvantages of docker and Kubernetes
Advantages of Docker
- Fast application development: Docker container contains the minimum set of software to run an application, so they are very lightweight. Due to this Docker containers can be easily deployed.
- Docker containers can be easily transferred: Docker containers can be easily moved from development to staging to production, and they will behave in the same manner irrespective of the environment.
- Very lightweight: Docker containers are very lightweight because they contain only the required libraries required to run an application.
- Cost-saving: One of the major advances of using docker is the High Return on investment. Companies can save a huge chunk of money if they deploy the application as a docker container.
- Security: Docker containers are running in a separate environment. While creating the dockerfile, you have the flexibility to add users who will have the required access to the application.
- CICD integrated: we can easily integrate the docker containers with CICD tools like Jenkins, Travis, etc.
Disadvantages of Docker
Some disadvantages of Docker are:
- Problem with data storage: As you know that the containers are volatile, and docker containers will not save the data on their own until or unless you have explicitly configured data volume. Although several solutions are present, they are not automated.
- Not as fast as bare metal: Although containers are very fast but not as fast as the application deployed in bare metal because of n/w overhead, etc.
- cross-platform compatibility: The containers which are designed to work on windows will not work in Linux and macOS and vice versa.
- Problem with Graphical applications: Docker containers are not very well suited for graphical applications.
Now let’s proceed further and see Kubernetes’s advantages and disadvantages:
Advantages of Kubernetes
Although Kubernetes provides a lot of advantages and some of which are:
- Increase productivity: If Kubernetes is set up properly in your system, It can increase productivity.
- Large community support: Kubernetes is very open-source and has a vibrant community. You can easily reach out to the community for any help.
- The future is containerization: As more and more production workload is shifting to containers. So now it is time to worth investing in Kubernetes.
- Kubernetes is cheaper: Running workloads in Kubernetes is cheaper if you compared it with running the application over bare metal.
- Multi-Cloud capability: With Kubernetes, users can run the workloads in single as well as in multiple clouds.
Disadvantages of Kubernetes
Although Kubernetes has many benefits, it has some disadvantages as well. Some of them are:
- Steep Learning Curve is required: One of the significant drawbacks of implementing Kubernetes is that it required a steep learning curve as there are so many things to learn before getting started with it.
- Sometimes can overkill the simple deployment: The people who do not have a must idea about Kubernetes feel that there are many things to be declared in YAML before actually deploying it on Kubernetes.
- Shifting an old workload is a nightmare: There are so many factors that need to be taken care of; if you have the workloads already running in the production and you are planning to shift your workload to Kubernetes.
- Setup Kubernetes cluster is difficult: Setting up the Kubernetes cluster is not straightforward and needs a lot of effort, but once the cluster is properly set up it will provide you a lot of benefits as compared to conventional deployments.
Now we have a pretty good idea about Docker and Kubernetes and their advantages and disadvantages. Now we are ready to understand the difference between Docker and Kubernetes.
Docker vs Kubernetes
Below is some of the significant difference between Docker and Kubernetes:
The basic difference between docker and Kubernetes
| Docker | Kubernetes |
|---|---|
| Docker inc develops Docker in the year 2013 | Google develops Kubernetes in the year 2014 |
| Setting up the Docker is relatively easy. It can be set up using a single command. | Setting up the Kubernetes cluster is quite complex and requires a lot of effort. |
| Docker can run on a single node. | A minimum number of masters and workers is required to set up the Kubernetes cluster. |
| Docker can run independently. | Kubernetes requires a container runtime to orchestrate |
| To deploy the application using Docker, we need to write the Dockerfile | To deploy the application over Kubernetes, we need to write the configuration in .YAML file |
docker and Kubernetes difference in commands
| Docker | Kubernetes |
|---|---|
| Docker containers can be managed using the docker command | You can manage Kubernetes resources by kubectl command-line utility. |
| In Docker, applications are running inside a docker container. | In Kubernetes, applications are running inside pods |
| To run a docker container: docker run -d httpd –name my-httpd -p 80:80 | To run an httpd deployment: kubectl run –image=httpd my-httpd –port=80 |
| To check the running container: docker ps | To check the running pods kubectl get pods |
This session will compare Docker with Kubernetes, although both tools serve different purposes. The other competition technology with Kubernetes is the docker swarm, and it is worth comparing both of them.
Kubernetes vs Docker swarm
Both docker swarm and Kubernetes serve the same purpose: container orchestrion, so why do we need to choose one over another? In this session, we will be comparing Kubernetes with the Docker swarm.
| Kubernetes | Docker Swarm |
|---|---|
| Autoscaling future is present in Kubernetes | The auto-scaling feature is not present in docker-swarm |
| Difficult to setup | Easy to set up and get started |
| GUI is available | GUI is not available |
| More widely used in production | Use by only a few companies. |
| Applications can be deployed in the form of pods, deployments, or a service. | Applications are deployed in the form of services |
| Scaling is comparatively slower | Scaling is faster as compared to Kubernetes |
| Manual load balancing can be configured. | It does not support load balancing. |
Docker and Kubernetes
This session will discuss whether docker and Kubernetes work stand-alone and what will happen if we plan to deploy them together.
Docker without Kubernetes?
Docker can be used standalone and does not require Kubernetes. But suppose you have a production workload and want a robust and easily scalable system. In that case, it is always recommended to use Docker with a container orchestration framework, whether it is Kubernetes, docker swarm, or openshift.
Kubernetes without Docker?
Kubernetes can not work without a container runtime. A container run time should be present for Kubernetes to function. You can use any container run times like RunC, cri-o, podman, or Docker.
Docker and Kubernetes together?
We have started our discussion with Docker vs Kubernetes, and you might be thinking that both technologies are rivals, but they are not. Infect, they are the perfect match made in heaven.
Most fortune 500 companies use Docker and Kubernetes together to deploy their production workloads. These two technologies complement each other and will continue to do so for a few years.
Kubernetes or Docker: Which Should You Adopt?
Docker and Kubernetes are compelling technologies, and they serve very different purposes. If you are new to the container world, I suggest getting started with Docker and deploying basic applications using docker containers.
And as the time process and number of users increase, you can plan to scale up your application using Kubernetes.
Conclusion
Finally, we have come to an end to this lengthy tutorial. We started with the basics of containers and understood what Docker and Kubernetes are. We also learned about the docker and Kubernetes advantages and disadvantages. Finally, we compared Kubernetes with Docker and docker-swarm.
We also learned how these two remarkable technologies could work together and give us better results. Please let me know in the comment box if you like this tutorial.
