Kubernetes vs Docker: Understanding the Fundamental Differences

A Quick Overview: In the world of modern software development, containerization has emerged as a game-changing technology. Among the leading containerization solutions, two names stand out as key players - Kubernetes and Docker. Each offers unique capabilities and addresses distinct aspects of container orchestration. This blog aims to provide an insightful overview and comparison of Kubernetes vs Docker to help you understand their respective roles and guide you towards making informed decisions for your applications.

Whether you are working on software application deployment or having cloud-native technologies and containers on your business radar, you must have heard about the raging debate on Kubernetes vs Docker.

Thanks to their community support and utility, these two open platforms are the most widely used tools in the DevOps services ecosystem. Although most people like to pit these technologies against each other, they are fundamentally a lot different, and choosing one over the other is rather irrational.

In essence, they are distinct technologies that can impeccably complement each other while building, deploying, and scaling robust and powerful applications. This is the reason the majority of present-day organizations are opting for DevOps containerization solutions to tackle their tech challenges, as per reports.

So, let’s look beyond the buzzes surrounding Docker vs Kubernetes and understand the true ‘difference’ between them before trying to leverage their business benefits.

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If your attention span is short, TL; DR is:

The difference between Kubernetes and Docker is that Docker creates individual containers, while Kubernetes orchestrates and manages those containers.

This is as simple as it can get. Below, we will go over the basics to explore Docker and Kubernetes, consider their benefits and drawbacks, discover their features, and more.

We will also cover the use cases of Kubernetes, how it can be beneficial to you, and how we can combine Kubernetes with Docker.

But first, some background checks!

First and Foremost, What are Containers?

If your organization needs to drastically accelerate innovation and deployment cycles, containers are the most important technical enablers. They are the standard unit of any successful software as containers work as a package to hold all the dependencies and codes of your software.

As a package of microservices, containers help in separating the content from its environment, i.e., its infrastructure and operating system. As the transport industry is immobile without shipping containers, Docker containers revolutionize the software industry.

You can run a standard Docker container anywhere, on local servers, in cloud services, on your personal computer (Linux, Mac, or Windows), and even on edge devices. They are easy to replicate as well, giving you the opportunity to build scalable apps and match the growing user traffic.

Containers are one of the best DevOps tools for software development as they allow you to break up the monolithic system of your business into containerized microservices, save time and effort with deployment and testing, and reduce the time to market from some months to a few days.

Even small teams can now create and package apps on their desktops and deploy them anywhere in the production environment or staging without worrying about hardware, operating systems, configurations, dependencies, etc.

What is Kubernetes?

Now that you know what containers are, let’s start with an overview of Kubernetes.

Also known as K8s, it’s a sophisticated and robust set of tools aimed at container orchestration. In the Kubernetes Docker argument, the Kubernetes is like the Tetris game where it selects the placement of the containers by orchestrating where those workloads get finished.

Different big and small firms use Kubernetes consulting solutions to automate their containerized apps. It makes more sense to use Kubernetes than manage containers individually.

Think of the architecture of Kubernetes as peeling back the layers of an onion. There is at least one cluster in Kubernetes deployments. A cluster includes nodes, and the nodes contain pods. These Kubernetes pods consist of a running set of containers. And a Kubernetes instance manages all these components.

This architecture might seem over the top, but it’s highly imperative to guarantee the all-time availability and fault tolerance that Kubernetes offers.

There are two planes that make up Kubernetes' architecture:

• Control Plane

It’s like the synchronizing brain of the cluster of containers.

• Worker Nodes

These are the machines that run and manage the containers.

How Does Kubernetes Work?

Kubernetes operates on a client-server framework, with a group of nodes that execute the containers, and a control plane responsible for overseeing the system's overall status. The control plane comprises various components, including the API server, etcd, scheduler, and controller manager, which collaborate to effectively manage the application development lifecycle within Kubernetes.

To efficiently organize containers, Kubernetes utilizes ‘pods,’ which serve as logical units capable of running one or more containers together. Pods enable the grouping of related containers and facilitate resource sharing, such as networks and storage.

Moreover, Kubernetes offers a declarative approach for specifying the desired state of the system, empowering users to define their application's configuration and deployment requirements in a straightforward and scalable manner.

Features of Kubernetes

Kubernetes has multiple unique features that have revolutionized the field of DevOps software development by allowing teams to shift their focus from routine maintenance and updates to app development. Take a look:

Self-Healing: Kubernetes can detect and troubleshoot container-related issues. These mechanisms help ensure that your systems remain operational and available without any disruptions.

Rollouts and Rollbacks: These features enable developers to deploy new application versions while having the ability to go back to previous versions if needed. This provides great flexibility and control over the software development lifecycle.

Autoscaling: It refers to the automatic adjustment of application resources based on predefined rules, such as increased traffic or resource utilization. This feature ensures that your apps can handle growing demands on the fly.

Resource Management: Kubernetes has advanced features like CPU and memory quotas to ensure that containers have access to the necessary resources for optimized performance and resource utilization.

Load Balancing: It’s a technique that distributes incoming traffic across multiple containers to improve availability and reduce downtimes. By evenly distributing the load, Kubernetes helps you maintain optimal performance and user experience.

Storage Orchestration: Helps mount the storage system you choose automatically, whether from a network storage system, a public cloud provider, or local storage.

Benefits of Kubernetes

The advantages of Kubernetes are numerous and have greatly eased the lives of developers and businesses alike.

1. Simplified DevOps

Kubernetes simplifies DevOps processes by introducing the concept of GitOps. It automatically aligns the deployment with the Git status and eliminates the need for manual synchronization. Developers can now update the Git history with desired changes, and Kubernetes takes care of updating the application accordingly.

2. Enhanced Productivity

Kubernetes offers a vast ecosystem of tools and services that enhance development efficiency. By providing a layer of hardware abstraction, it enables you to build robust self-service applications. Teams can make changes more quickly and manage hardware resources as a unified entity through the Kubernetes engine.

3. Universal Support

In the era of cloud computing, Kubernetes demonstrates universal support by being fully compatible with major cloud platforms such as AWS, Azure, and GCP. Its availability on these platforms simplifies setup and provides a cohesive developer and business experience.

4. Growth and Adaptability

Kubernetes also proves to be future-proof due to its rapid growth and flexibility. The ecosystem continually expands, with new tools and APIs developed by enterprises and communities. The technology's containerized structure enables seamless migration between cloud platforms and provides the needed compatibility and flexibility for evolving needs.

5. Extensive Community

Kubernetes has a broad ecosystem, with its open-source nature encouraging the creation of custom tools. With a growing number of enthusiasts embracing Container as a Service, Kubernetes communities are forming to support one another in solving issues.

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What is Docker?

Now that you have got an idea about containers, let’s move on to understand what a Docker container is, as these two have become highly synonymous.

Just like we use the term ‘Google’ for internet search and ‘Xerox' for paper copies, Docker has become an interchangeable term for containers. But at its core, it’s a lot more than just a container.

Docker is an open-source platform for developers to create, run, and share containerized apps by separating them from the infrastructure for faster delivery.

With Docker CLI (Command Line Interface), developers can easily interact with Docker to communicate with the Docker client to execute commands like docker run or docker build.

Docker consists of five primary components as follows:

• Docker Build

As the name suggests, Docker build helps in creating container images that are basically the blueprint of the container. Without these images, you cannot run an app.

• Docker Compose

You can define and run multi-container apps with Docker compose. You can compare this tool with GitHub, which holds the code repositories to get integrated with the apps.

• Docker Hub

Docker hub is a registry that enables everyone in your team to find and share the images created with Docker build.

• Docker Engine

Docker engine is the same as a Docker container that helps other containers run. From Windows to Mac to Linux, it can support almost every environment.

• Docker Swarm

Docker swarm helps in managing a bunch of Docker engines, usually on discrete nodes.

Launched in 2010, Docker is both an open-source and propriety software (community and enterprise) that brings the notion of containers into the mainstream.

Thus, it became the most recognized container runtime. Eventually, it paves the way for the creation of other platforms like Kubernetes.

How Does Docker Work?

On the other hand, Docker employs a client-server architecture to create, execute, and manage containers. In this structure, the client interacts with the Docker daemon, which handles essential tasks like image creation, container startup and shutdown, as well as network and storage management for containers.

Features of Docker

Docker offers a range of features that benefit developers:

Containerization: Developers can package their applications in containers, leading to consistent execution on any host with Docker runtime.

Portability: Containers like Docker are designed to be portable and lightweight to facilitate application deployment on various platforms.

Image Management: It provides a centralized repository for storing and sharing Docker images. This results in simplified application distribution.

Volumes and Bind Mounts: Docker provides options for managing data persistence through volumes and bind mounts. As a result, application state management becomes a lot easier.

Multi-Host Networking: Docker offers a built-in overlay network for multi-host networking. This allows containers to communicate even if they are on different hosts.

Open-Source Platform: One of the most significant aspects of an open-source platform is its ability to choose the preferred technology for completing a task.

Benefits of Docker

Now, let's explore some advantages of using Docker:

• Cost-Efficiency

Docker significantly reduces deployment time, with image deployment taking only seconds. By putting processes in containers, provisioning servers, allocating resources, and setting up infrastructure become quicker. And since you’re sharing processes with new applications, it speeds up the deployment process and saves a lot of time.

• Stable Environments

Docker containers create isolated and predictable environments. This leads to increased productivity by reducing debugging time and enabling faster deployment of new features. Scaling up during high-demand periods and scaling down during quieter times help developers optimize resource allocation and cost-effectiveness.

• Scalability

Docker allows you to scale your application according to your business needs. Its lightweight and portable nature enables easy scaling up or breaking down of applications. Additionally, Docker offers a variety of container management options when working with multiple containers.

• Portability

Another great benefit is the portability of Docker. Once you deploy a tested containerized application on any system, you can be confident that it will run smoothly without complications.

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Kubernetes vs Docker: What are the Key Differences?

Here is a thing – if you are comparing Docker versus Kubernetes, you are basically doing it wrong. Instead, we should make the comparison between Docker Swarm vs Kubernetes as these technologies are on the same page.

Launched in 2013, Docker Swarm is Docker’s native scheduling and clustering tool that enables developers and IT administrators to build and manage a cluster of Docker nodes as a discrete virtual system.

There are two main types of nodes in Swarm mode – worker nodes and manager nodes. Worker nodes are basically the containers that execute the overall process, and manager nodes orchestrate the cluster, perform steady quality checks, and other important tasks.

Now you are probably thinking that Kubernetes does these exact same things, right?

Well, not entirely. Even though they share a few similar functionalities, there are some significant differences between Kubernetes vs Docker that offer one among these two an upper hand, along with mitigating the challenges in DevOps implementation with solutions.

So, let's get going with Kubernetes vs Docker Swarm in detail!

Set-Up

In terms of setup, setting up a Kubernetes cluster is comparatively easier as you would need only two commands. However, the cluster is not that strong. On the other hand, Clusters in Docker Swarm are pretty strong, and hence, setting them up is quite challenging.

Customization

Kubernetes is highly customizable and massively comprehensive, whereas Docker Swarm is less customizable and extensive.

Tools

Between Docker Swarm vs Kubernetes, Kubernetes offers in-built tools for monitoring and logging, but Docker Swarm has third-party tools for the same.

Autoscaling

One of the biggest differences between Kubernetes and Docker Swarm is that Kubernetes allows autoscaling, whereas Docker Swarm has no scope for it.

Load Balancing

Kubernetes allows you to manually configure the setting of load balancing, but when it comes to Docker Swarm, it performs auto load balancing.

Fault Tolerance

Talking about fault tolerance, Docker Swarm provides high fault tolerance, but contrastingly, Kubernetes comes with low fault tolerance.

Community Support

Among all the container orchestration tools, Kubernetes has the largest and the most robust community base. On the flip side, Docker Swarm has a decent community but is not as great as Kubernetes.

Projects and Products

As long as you invest in its infrastructure, Kubernetes is a free, open-source project. Docker has two versions – Enterprise Edition (paid) and Community Edition (free).

Container Image Management

Kubernetes does not have any integrated image registry. It pulls images from Docker image registries like the Docker Hub. In contrast, Docker has the Docker Hub registry. It is also compatible with other registries allowing you to save and share images.

Security

In terms of security, Kubernetes needs you to create authentication methods like bearer tokens manually. However, Docker Swarm nodes deploy TLS mutual authentication and encryption to protect what they communicate with each other.

Release and Updates

Another notable difference between Docker and Kubernetes is the frequency of new releases and updates. Due to its popularity, Kubernetes has frequent updates with up to 4 updates/year. Docker has a busier schedule for releases, with numerous updates for each tool in a year.

Networking

Between Kubernetes and Docker, Kubernetes does not have a native networking solution, whereas Docker provides multi-host networking.

Web User Interface

Kubernetes does not have an easy-to-use web-based user interface, but Docker’s dashboard has a login page and web console for easier cluster administration.

Kubernetes vs Docker: What’s the Relationship Now?

More often than not, Docker engineers were facing difficulties in managing containers, especially with extensive production environments. This issue compelled Google to design, develop, and use Kubernetes for almost twenty years before handling it to CNCF (Cloud Native Computing Foundation) in 2015.

As a result, Kubernetes gained immense popularity for orchestrating a cluster of containers across almost 5000 nodes. At the same time, Docker emerged as an equally significant container runtime layer for Kubernetes.

So, now the question is – Is Docker an essential requirement for Kubernetes?

While Docker and Kubernetes were inseparable in the very beginning (as the prior was the only supported engine), Docker was not supposed to run inside Kubernetes. This issue led the Kubernetes team to implement an API called Container Runtime Interface (CRI). The goal was to make the platform less dependent on Docker and more flexible by letting us choose among multiple runtime options.

But the Kubernetes team faced a new challenge with this change since Docker does not support the CRI. This is why they had to develop an adapter named ‘Dockershim’ for translating CRI operations into Docker-oriented commands.

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About the Dockershim Deprecation

In 2021, the Kubernetes development team disclosed that they are deprecating Docker; meaning Kubernetes will not anymore provide the special three-layered support to Docker as it previously did. This changed the whole Kubernetes Docker story.

Although Docker was the first and only supported runtime for a while, it never planned to stay in the long run. Kubernetes 1.20 lays off the transition away from Docker and deprecates Dockershim.

Once you complete the transition, the stack becomes remarkably smaller.

It changes from this:

To this:

The upshot is fewer dependencies and reduced bloat required on each node.

In simple words, Docker is hefty. A lightweight container runtime, such as CRI-O or containerd, is more helpful in getting better performance and integrating DevOps in software development processes. For example, according to Google benchmarks, containerd consumes less CPU and memory, and Kubernetes pods take less time on it compared to Docker.

Apart from that, we can consider Docker “technical debt” in some ways. The only thing Kubernetes requires from Docker is containerd – the container runtime. The rest is overhead, at least as far as Kubernetes is concerned.

In simple words, Kubernetes is a system to operate containerized apps at scale, whereas Docker is a set of tools to build, run, and share individual containers.

Despite everything, here are a few things you can do with K8s vs Docker:

• Docker images (OCI format) and Docker files allow you to develop container images for Kubernetes.
• Since Kubernetes pulls from Docker registries like Docker Trusted Registry and Azure Container Registry, storing and sharing Docker images in Docker Hub is possible.

The only difference is that Kubernetes does not allow you to use Docker as a container runtime under it anymore.

Benefits of Using Kubernetes with Docker

A typical app development life cycle begins with designing and building the codebase. As your team will work on a standalone project within a classic IT environment, each member needs to adopt an isolated and synchronized environment to create and push code snippets to the original code.

The most important goal is to build a system where your developers have to code once and run everywhere.

Containers can help you exactly here. They empower developers to write code locally, detect potential issues, perform debugging, and push back the changes to Docker images. They can also share the codebase with others, and after developing the app, they need to deploy the codebase.

Now suppose it needs three containers for deploying the app. They deploy the app as microservices with multiple clusters containing numerous nodes to scale up the app after a certain period.

And here comes the actual challenge – maintaining the multi-cluster system, controlling security, performing load-balancing, meeting software quality metrics and KPIs, and optimizing networking.

These are what Docker Swarm brings to the table. But on the other hand, Kubernetes containers offer a better solution for complex and large architectures with the help of pre-configured isolation mechanisms like namespaces. You can also assemble container resources with access permissions, staging environments, and so on.

Kubernetes essentially enables software engineers to collaborate on complex architectures and gain seamless access to resources without troubling the whole app.

Hence, if you combine Kubernetes with Docker, you will be able to build a baseline for microservices architecture with highly scalable orchestration and faster delivery.

In a nutshell, Kubernetes with Docker will help you:

• Develop scalable apps with high load withstanding power
• Build a robust infrastructure with greater availability. You can access the apps even if a few nodes go offline.

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Can You Use Kubernetes without Docker?

You cannot create or manage containers and images with Kubernetes as it does not include those functionalities. For orchestrating, it definitely requires a container runtime.

Therefore, you need a container service to use with Kubernetes, such as runC, CRI-O, etc. Since Docker is the most recognized container, developers commonly use it with Kubernetes.

Can You Use Docker without Kubernetes?

It's a common practice in the development environment to use Docker for building and deploying apps without container orchestrators like Kubernetes.

But things are a bit different in production environments as the advantage of using container orchestration tools prevails over the added complexity.

As a matter of fact, many cloud service providers like Google, AWS, or Azure offer orchestration tools that balance out the additional complexities.

Docker vs Kubernetes: Which One is Right for You?

The question of what is the best choice between Docker and Kubernetes is not a tricky one. After all the discussions, the answer might have become very obvious to you – both.

Though you can use Kubernetes with other container runtimes and sources, it works best with Docker. In fact, developers wrote much of Kubernetes’ documentation while keeping Docker in mind.

Additionally, Kubernetes has many Docker-centric tools, such as Kompose, that help in converting Docker Compose settings and commands. The most basic and common use case of Kubernetes is Docker+ Kubernetes.

And if we talk about Docker, it has effectively embraced Kubernetes and provided its own integrated Kubernetes distribution. In late 2019, Mirantis acquired Docker Enterprise (as well as Docker’s renewed interest in developing tools), which implies Docker’s dependency on Kubernetes and other container services. Mirantis underlines this with their stated intention to make Kubernetes the default orchestrator for Docker Enterprise by eliminating Docker Swarm.

Long story short, both Docker and Kubernetes are industry standards with their individual prowess. Together, they can offer you an efficiently integrated platform to manage, deploy, and orchestrate containers at scale and get started with DevOps CI/CD pipelines effectively.

So, the difference between Kubernetes and Docker is that Kubernetes is a container orchestration technology while Docker is for building and running containers.

The subtle difference between them was never really a topic of concern; it was always Kubernetes and Docker, and at this time, it is even more true.

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To ConcludeContainers are some of the fascinating inventions of technology. They empower us to perceive systems and services in an entirely modern and digital way. Both Kubernetes and Dockers are here to stay – they are constantly transforming to change themselves into something greater in the upcoming days and to respond to the rapid demands of microservices.In this context, implementing container technology with Dockers and Kubernetes is something your infrastructure requires the most. Developing software for the latest container management platforms will not only make your apps more scalable but future-proof as well. Holding on to the old virtual machine may work as of now, but eventually, in the near future, you will have to dig a big hole in your pocket by migrating everything into containers or leaving your projects high and dry.Hence, for cost savings and rapid deployment, you must migrate to container-centric platforms. For example, Kubernetes helped Booking.com develop 500 apps in just eight months.We hope you will not get swept by the jargon of Kubernetes vs Docker anymore if someone brings up the topic. And to learn more about these amazing technologies and implement them in your next projects, reach out to us for best-in-class containerization solutions crafted by our seasoned software engineers.