The Docker vs. Kubernetes debate is common in the containerization world. Although most people like comparing Kubernetes and Docker, the two technologies are not exchangeable—you cannot choose one over the other. They are essentially discrete technologies that can perfectly complement each other when creating, delivering, and scaling containerized applications.
In fact, the best at par comparison would be Docker Swarm vs. Kubernetes, which we’ll talk about later.
This article explains the workings of both technologies and clarifies their similarities and differences so that you can become confident in navigating the rapidly expanding container ecosystem.
Docker is a popular platform that makes it easy to develop, deploy, and run applications as standalone, portable containers. Containerization is an innovative form of operating system virtualization that lets you package up code and all its dependencies as self-sufficient units, ensuring the application runs consistently across different computing environments.
Docker, Inc. released Docker in 2013. Docker is distributed both as proprietary software (Enterprise Edition) and as open source software (Community Edition).
Though the concept of isolating environments is not new—and several containerization technologies were available prior to Docker’s launch—Docker has grown to be the de facto containerization platform in recent years. It has greatly simplified the running of container applications.
As containerized applications become gigantic and dynamic, it becomes difficult to operate and realize their full value. When several containers are deployed across several server environments, many problems arise. For example, it becomes difficult to scale numerous container instances, ensure smooth interaction between different containers, and coordinate and schedule containers.
This is where Kubernetes comes in to address most of those complexities.
Kubernetes, usually stylized as K8s, is a popular open source platform for orchestrating containers. It automates the deployment, scaling, and management of containerized applications, such as those built using Docker.
Kubernetes was launched by Google in 2014 but is now controlled by the Cloud Native Computing Foundation (CNCF). It has grown to be the de facto tool for orchestrating containers and running distributed applications.
Kubernetes takes the containerization concept a notch higher. It assists you in handling some of the operational difficulties when deploying and managing multi-container applications across multiple hosts.
Kubernetes distributes and schedules containerized apps across a cluster of physical or virtual machines—rather than running them on one server. This way, apps running in Kubernetes function like a single entity, although they may actually comprise an assortment of loosely coupled containers. Clustering is a vital containerization concept that enables admins to build a cohesive and cooperative group of systems that offer redundancy.
With Kubernetes, you can automatically scale container apps on the fly based on the available compute resources, self-heal and health-check your apps, manage service discovery, perform horizontal scaling and load balancing, and implement rollouts and rollbacks. This level of automation has greatly transformed the containerization space.
Even though Docker and Kubernetes are separate technologies, they actually complement each other and work great together. In fact, they have a symbiotic relationship.
Docker is at the core of containerization technology—it allows you to create and deploy application containers. If your application is still simple, Docker has the essential infrastructure for managing its lifecycle.
As your containerized application becomes bigger and more complex, possibly needing multiple clusters and more sophisticated management, Kubernetes becomes a handy tool. It offers a useful orchestration platform for your Docker containers. Kubernetes does not create containers; it actually requires a container tool to run, of which Docker is the most popular option.
So Docker vs. Kubernetes actually points to their ability to work together to realize the promise of the containerization technology—code once and run anywhere, regardless of the scale.
Using Kubernetes with Docker results in the following benefits:
Most users compare Kubernetes vs. Docker, which is misconstrued. The most apt comparison is Kubernetes vs. Docker Swarm, which are similar container orchestration technologies.
Docker Swarm, released in 2013, is an open source project that Docker, Inc. manages. It is the native clustering solution for Docker. Swarm provides full integration capability with Docker’s ecosystem.
Although Docker Swarm and Kubernetes offer many similar functionalities, there are some fundamental differences that set each of them apart.
Primarily, Docker Swarm focuses on ease of use and provides a simple way to install and configure—especially for inexperienced operators. Swarm works with existing Docker tools, allowing you to manage both Docker and Swarm from the same command-line interface. This lowers the learning curve when moving to a container orchestration solution.
Kubernetes is a bit more complex. It’s tedious to install and configure. However, once set up, the Kubernetes cluster is very strong and offers a rich set of functionalities. Though Docker Swarm is simpler to use, its cluster is not very strong. Another difference is that Kubernetes comes with its own GUI, while Swarm requires a third-party GUI tool.
So between Docker Swarm vs. Kubernetes, which one should you choose?
If you’re just getting your feet wet, go for Docker Swarm. Once you’ve fully immersed yourself in the orchestration world and need something that can support higher complexity and demands, go for Kubernetes.
Any Docker vs. Kubernetes comparison would be better framed as a “both-and” instead of an “either-or” question. They both work together to allow you to create, release, and scale applications efficiently with containerized technologies.
Docker and Kubernetes are a powerful combination that together can help bring value to your applications, especially when adopting continuous integration/continuous delivery (CI/CD) and other DevOps practices.
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