Read this in-depth review and comparison between Kubernetes Vs Docker used to build, deliver, and scale containerized applications:
In a recent survey, the Cloud Native Computing Foundation (CNCF) figured out that 84% of the total respondents in question were using Docker and Kubernetes in their production environment by 2019. Naturally, it has led many organizations into thinking whether they should shift their production environment too.
However, there’s a lot of confusion among the newbies surrounding the fact that whether they should use Docker or Kubernetes to deploy their software or not.
Table of Contents:
Understanding Kubernetes And Docker
The discussion around Kubernetes Vs Docker is at times drafted as “either-or”, that is, Should we use Docker or Kubernetes for my ongoing project? This is like comparing cars with carpets. It is a misconception that you always need to choose only one from them.
When you break down the phrase Kubernetes Vs Docker, it doesn’t always mean what the experts intend to say. This is so because Docker and Kubernetes are not competitors. In short, Docker is a platform that allows you to perform containerization, and Kubernetes allows you to perform container orchestration for platforms like Docker.
This means that the best way is to use these platforms is simultaneous. It would be easier to understand this concept when devised as a “both-and” question, i.e. Can I use both Docker and Kubernetes simultaneously? And the answer to this question is a big “YES”.
Docker and Kubernetes are essentially different technologies and they work well together, allowing you to build, deliver, and scale containerized applications.
In this article, we will gaze beyond the hype that surrounds both Docker and Kubernetes. We need to understand what these words actually mean before we run our entire technological stack on top of them. So without any further ado, let’s dive deep and gain some valuable insights on this topic.
Mutualism Between Kubernetes And Docker
As discussed earlier, the question Kubernetes vs Docker? is quite absurd. We need to understand that one is not an alternative to the other. In fact, Docker can run without Kubernetes and vice versa. But they can get plenty of benefits if used simultaneously.
Let us understand better.
We know that containerization is an approach where we run applications on an operating system, isolated from the rest of the system. We often get an illusion that our application is getting its own private instance of the operating system. But more often than not, there are other containers running on the same system.
Docker provides us with a platform that allows us to create, manage, and deploy multiple containers in one system. Kubernetes is just a cherry on the top.
Suppose you have a microservice architecture where you have multiple containers running in multiple operating systems (hosts). These are called nodes and can be virtual machines or simple metal servers. You can leverage Kubernetes to automate the process of container load-balancing, networking, provisioning, scaling, and security.
And all of these can be done with a single command line in a system. It allows you to create a Kubernetes cluster that contains several nodes managed by a single instance or master node.
You might be wondering why you need to have multiple nodes when you can create a multi-container single node. There are two main reasons behind this.
These are:
- To increase the scalability of your application. In case, if the workload increases, you can simply add more nodes to the Kubernetes cluster without affecting other nodes.
- To provide robustness to the infrastructure. Even if some nodes become unavailable due to failure, your application will not be affected.
For example, you have an application for an online railway ticket reservation. Suppose you have deployed your application as a microservice architecture where you have a set of nodes set up for managing information related to the customer, another set of nodes for managing the information related to the schedule of trains and platforms, and so on.
Now, you want a node from the customer-related cluster to share some information with another node from the train-schedule-related cluster. With the help of Kubernetes, you need not find the system related to the node and perform the operation there. Since you manage all the nodes from all the clusters from a single host now, you can easily do so from a single command line.
What Is Docker
In the good old days, software companies used to deploy virtual machines for each of their applications. While they fulfilled almost all the requirements, their down-side was that they were very heavy and allocated a huge chunk of the memory and hardware resources of the underlying machine.
However, with containerization, it could be avoided because containers give us the same benefits as OS-level virtualization, thus consuming fewer resources.
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Docker provides us with an open-source platform that has the ability to develop, package, and run applications in contained environments known as containers. It allows you to run multiple containers in a single machine with absolute isolation and security.
Here’s a list of reasons Docker is so darn popular among the DevOps community.
- Developers can leverage Docker containers to write code locally and share them with their team, all with the help of containers.
- They can create isolated test environments as containers, push their code and make changes in it, connect them with CI/CD tools and automate test executions.
- In case a bug is reported, it can be fixed within the environment and pushed back.
Recommended Reading =>> Docker Tutorial: Introduction To Docker.
What Is Kubernetes
Imagine a situation. Suppose you have been using Docker for deploying your application for a little while now. Let’s say, you have set up 3 servers in the initial stage. Now, your application starts getting traction, and the traffic has increased significantly. The 3 servers that you deployed earlier cannot handle the load, and you now want to scale up your services.
How will you scale up from 3 to 50 servers? And how will you decide which node should be a part of which cluster and how to monitor all these simultaneously? This is where Kubernetes fits right in.
Kubernetes creates a perfect blend of the mixture when used with Docker Containerization. It is a container management software (container orchestration tool) that helps you to manage containerized applications in all types of environments. It’s a system that can be used to automate the scheduling, deployment, and scaling of thousands of clusters containing multi-container nodes.
It has a modular architecture that consists of three main components – Control Plane, Nodes, and Pods.
The Control Plane facilitates the orchestration process and provides a means for communication, storage, and scheduling. Nodes provide the collective computing power for multiple clusters and pods define what resources, memory, and CPU need to be allocated for containers to run.
[image source]
>> Official guide of Kubernetes
Differences Between Kubernetes Vs Docker
Instead of differentiating Kubernetes with Docker, it’s more apt to compare Kubernetes vs Docker Swarm.
Docker Swarm is Docker’s very own container orchestration system, which solely focuses on clustering Docker containers. It is tightly integrated with the Docker ecosystem and uses its own API. It allows developers to create and manage a cluster of nodes (Docker nodes) as a standalone virtual system.
We can categorize every node in Swarm mode as a manager or worker node. The manager node orchestrates the cluster, performs regular health-checks, and other significant processes. The worker nodes, which are actually the containers, just execute the task.
>> Know more about Docker Swarm in this comprehensive guide.
Now, you might wonder that this is exactly what Kubernetes does. Well, that’s not it. There are a few significant differences between them that give one an upper hand over the other.
Let’s discuss some of them in the below table:
| Docker Swarm | Kubernetes |
|---|---|
| Setting up clusters is challenging. However, Cluster strength is quite strong. | It’s very simple to set up a cluster. In fact, it just requires two commands. However, the cluster strength is not as strong. |
| It’s less extensive and customizable. | It’s highly comprehensive and massively customizable. |
| Does not provide autoscaling. | Allows autoscaling. |
| It allows you to use 3rd party tools for monitoring and logging. | It has its own in-built tool for logging and monitoring. |
| It performs auto load-balancing. | You need to manually configure load balancing settings. |
| It is optimized for a single large cluster. | It is optimized for numerous small clusters in a microservice architecture. |
| It has high fault tolerance. | It provides low fault tolerance. |
| It has a good community base but not as good as Kubernetes. | It has the largest community among all the container orchestration tools. |
It’s quite evident that if you have a large architecture with multiple clusters, it’s better to go with Kubernetes than Docker swarm as a container orchestration tool.
Similarities Between Kubernetes And Docker
It’s important to understand that these are more than mere technologies. It’s about the kind of support that you get from the community that decides their worth. These result from like-minded people getting together and sharing their bright ideas. This explains very well what they have in common.
- Both of them are very suitable to be used in microservice architectures. They make managing thousands of nodes and clusters seem like a petty task.
- Both of them are open-source projects and thus, modifications are frequent and with fewer bugs.
- They are written in the Go language. This allows them to be shipped as lightweight binaries.
- To define deployments and application stacks, they use human-readable YAML files.
In short, you can learn about one technology without even having a clue about the other and could still get your work done pretty easily. However, it would be much beneficial for you, if you start with a small concept like Docker, move on to Docker swarm to manage a small number of clusters, and then use Kubernetes to manage multiple and large clusters of nodes.
Docker And Kubernetes: Better Together?
Let’s understand a typical application development cycle. The work starts with designing and developing the codebase. In a typical IT environment, a team or a group of teams work on a single project. Hence, it’s essential that a synchronized and isolated environment is adopted so that each member of the team can develop code snippets and push them to the original code.
The main agenda is to develop a system wherein developers need to code once and run anywhere.
This is exactly what Containers bring to the table. With the help of containers, developers can write code locally, identify bugs, perform debugging, and push back the changes to the docker images. It helps them to share the codebase among the team members. After developing the application, it needs to be deployed.
Let’s say initially it uses 3 containers to deploy the application. After a certain period, to scale up the application, the application is deployed as a microservice architecture with several clusters containing multiple nodes. Now, the main challenge is to maintain the multi-cluster system, perform networking, load-balancing, and maintain security.
Here, Docker Swarm can be used. But, as discussed earlier, for large and complex architectures, Kubernetes provides a better solution compared to Docker Swarm. It also has an in-built isolation mechanism, like namespaces. This allows us to group container resources with the help of staging environments, access permissions, etc.
It essentially allows developers to gain easy access to resources and to collaborate on even complex architectures without troubling the entire application. Thus, combining operational practices with Kubernetes and Docker containers creates a baseline of microservice architecture with faster delivery and highly scalable orchestration.
In short, combining Kubernetes with Docker:
- Help you create a robust infrastructure, with high availability. Even if some of your nodes go offline, you can still have access to the application.
- Let you create a scalable application that can withstand high load.
Industry-Wide Adoption Of Docker and Kubernetes
Such concepts sound very cool in theory. But the major concern is what good does it bring to the industries? Is it economical? Does it help them to grow their businesses, reduce downtime, and save resources in terms of both human hours and computational time?
Changing an entire technological stack might be very expensive, especially when applications are deployed on a very large scale. The question arises here, is it worth it for IT industries to finally start adopting Docker with a touch of Kubernetes. The answer is yes. And the reason behind this is two folds.
Docker in Production
If you are considering a microservice architecture for your application, you shouldn’t doubt adopting Docker Containers for deploying your application. It’s quite a mature technology, with great infrastructure, and tons of features that will make the lives of your developers quite easier.
Kubernetes in Production
Most startups or even big giants blindly jump into Kubernetes without even understanding the basics of distributed systems. They try to host simple websites or small applications by setting up Kubernetes clusters. Second, they try to add their own sauce, for example, network plugins, service meshes, etc. These are open source and seem to be quite appealing.
However, deploying them in production, especially for small applications, can cost them a lot of resources which could have been easily avoided.
Instead of doing this, what organizations can do is use cloud-hosted Kubernetes platforms to run their applications. This can be quite handy to avoid node failures and is very easy to maintain.
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In the above figure, you can see a simple example of how you can use Container along with Kubernetes to build, manage, and host your application.
The flow:
- Use IDE to develop code bases and commit changes to platforms such as Github.
- You can use Github to trigger new builds on cloud platforms like Azure DevOps.
- They can help you package microservices as containers and push them to their official container registries.
- Then, you can deploy containers to deploy AKS clusters. They can be used to streamline horizontal scaling, secret management, load balancing, and self-healing.
- Use active directories to get access to the resources and secure them.
- Admins have a separate portal to access the app, while users can access them through websites.
- You can use databases to store and retrieve useful information.
Can you use Docker without Kubernetes?
In development environments, it’s quite a common practice to use Docker Containers to create and deploy applications without using a container orchestration tool like Kubernetes. However, in production environments, the profits of using container orchestrators outweigh the additional complexity.
In fact, many cloud services like Azure, AWS, GCP, etc. provide orchestration tools which makes a tradeoff with the added complexities.
Can you use Kubernetes without Docker?
Kubernetes does not include its own functionality for managing or creating containers and images. It needs a container runtime for it to orchestrate. It can be used with any container service, but since Docker has the largest market share, it’s commonly used along with Docker.
Containers And A New Age of Cloud Computing
Docker wasn’t introduced as an OS-level virtualization tool. It is marketed as a Software packaging mechanism. With the help of Dockerfiles, it has become a lot easier to carry out automated builds. Docker-compose has helped standardize complex multi-container deployments on cloud environments.
With the services provided by cloud environments such as AWS, GCP, Azure services, it is now used at its extreme to provide complete CI/CD solutions. This involves creating and testing Docker images and managing repositories hosted on the cloud.
In fact, container orchestration tools like Kubernetes have allowed containers to stop being stuck on single computers. Thus making the cloud an enticing place for container technologies. Gradually, for every cloud-dependent service, containers will become the new normal.
Adoption Mindset For Docker vs Kubernetes
The benefits are obvious. Deploying applications on Docker means that you can run them on any Linux machine. It makes it machine-independent. You can break your software into several microservice architectures and pack each of them as a container. You can push new features with well-defined docker files.
For example, if you want to include data analytics in your application, just spin up a Hadoop container.
Similarly, both users and cloud providers benefit immensely by adopting Kubernetes. Since it requires container runtimes, cloud providers get a high number of containers using their resources. Users can deploy software across the globe, which allows them to reduce latency and provide a better customer experience.
Increasing Support For Docker And Kubernetes
Companies like Google, Amazon, IBM, Microsoft, and Red Hat offer well-managed Kubernetes under the CaaS (Container As A Service) model. Since it’s an open-source tool, it attracts dozens of players to develop tools to perform networking, logging, monitoring, storage, and automation.
Global players like Blackrock, Uber, NYT, eBay, Goldman Sachs, etc. massively use Kubernetes in production. Over the last 3 years, it has been adopted by a diverse community of developers.
Frequently Asked Questions
Q #1) Does Kubernetes use Docker?
Answer: Kubernetes is a container orchestration tool that helps you manage a large cluster of containers efficiently. Whereas, Docker is an open-source platform that provides container services that allow you to build, manage, and deploy applications. Both can exist independently, and none of them uses the other. However, they can benefit immensely from each other when used together.
Q #2) Should I use Kubernetes or Docker?
Answer: It should not be an either-or question. You can use both of them simultaneously to easily manage complex microservice architectures. Docker allows you to create containerized applications. Kubernetes lets you manage multi-container clusters very easily.
Q #3) Can Docker run without Kubernetes?
Answer: Yes, Docker can run without Kubernetes. In fact, if you have a small application or even a small microservice architecture, it’s better to use Docker alone to build and manage it. You can start scaling it using Docker Swarm and then move on to Kubernetes when your architecture consists of multiple clusters of nodes.
Q #4) Is Kubernetes a PaaS?
Answer: Platform as a service or PaaS is used to create a layer of abstraction on top of cloud providers which lets you deploy and manage your applications on the cloud. Kubernetes can run anywhere whether on the cloud or even in a locked closet. It’s better to categorize it as Kubernetes as a Service (KaaS).
Q #5) What should I learn first, docker or Kubernetes?
Answer: Kubernetes is a container orchestration tool. It lets you manage large clusters of container nodes. Working with Kubernetes requires you to have container runtimes. Hence, it’s important that you first have a good grasp of container technologies such as Docker.
Q #6) What is Kubernetes in simple words?
Answer: Kubernetes is a container orchestration tool that lets you manage large clusters of container nodes that are deployed as a microservice architecture. It lets you automate scheduling, networking, logging, and scaling your multi-container application.
Conclusion
In this Docker and Kubernetes tutorial, we started with a basic introduction of the new hype Kubernetes Vs Docker. We understood why it shouldn’t be an “either-or” question, but more of a “both-and” question. We then moved on to discuss the relationship between Docker and Kubernetes and saw how they actually complement each other.
We then jumped on to discuss the basics of Docker and Kubernetes describing their use-cases with real-life examples.
We then understood the difference between Docker Swarm vs Kubernetes and how Docker Swarm can be used in place of Kubernetes for small microservice architectures. We looked at why Docker and Kubernetes are better together. Moving on, we discussed how the industry has welcomed Docker and Kubernetes and how they are used in production environments.
We presented you with a simple architecture explaining the various components that actively play a role in a typical DevOps environment and how the flow works.
We then discussed whether or not we can use one without the other. We looked at why containers with clouds are the new future. And summed up our article discussing the adoption mindset behind using Docker vs Kubernetes and how the tech giants have come together to increase the support for such a beautiful open-source tool.