Kubernetes vs Docker: The Difference Explained

If you’re trying to decide between Docker and Kubernetes, you’re unlikely to reach a definitive answer. These two technologies are so fundamentally different that you can’t compare them directly.

However, “one versus the other” underscores the importance of understanding the two. What do they do? How do they do it? What benefits does each one provide? This article will explore these questions to help you understand where each tool fits into your development process.

Kubernetes and Docker: Different Tools for Different Tasks

Modern applications are intricate and require installing various frameworks and libraries onto your device. Fortunately, you can consolidate your application and its required resources.

This process is called containerization, and it entails combining applications and all their necessary dependencies into a standalone unit — the container. Packing an application like this makes it far more portable and convenient to deploy and manage.

Furthermore, containerization can alleviate some of the difficulties you might encounter when trying to replicate your deployment environment for testing. In contrast to traditional application architecture that requires you to build a separate testing environment manually, containerized applications allow you to test in an environment identical to where you’ll deploy your app.

Containers also enable deploying and running multiple application components across a microservices architecture. This means that your app resources share the same hardware, and you maintain greater control over each component and its lifecycle. Containers are lighter than virtual machines because they leverage the host operating system (OS) kernel and don’t require hypervisors.

In cloud environments, containerization technology makes it possible to provide operational efficiency, portability when migrating, environmental consistency, and seamless scaling.

What Is Docker?

While multiple containerization technologies exist, Docker remains the most popular and widely known. It’s an open-source containerization tool that creates an ecosystem where you can deploy, manage, and share your applications.

Docker launched in 2013, enabling containerization with unparalleled efficiency and ease of use. Its innovative features addressed several issues that had previously hindered developers from practicing container-based development.

The core component of Docker is Docker Engine, which hosts its containers. Docker Engine runs on the host OS and interacts with containers to access system resources. Docker also uses YAML configuration files that specify how to build a container and what runs inside it. This is one reason why Docker is portable and easy to troubleshoot.

Docker containers can communicate with one another over defined channels, and each container has a unique set of applications, libraries, and configuration files. They can contain any application and run on any server. This improves the application’s flexibility and portability, enabling it to run in various settings, including on-site, public, or private cloud.

Container Orchestration with Kubernetes

Modern software relies heavily on microservices, independently running components you can deploy easily and update rapidly. Containers are useful for hosting microservice architecture. However, as applications become increasingly complex, they’re difficult to manually manage, maintain, and migrate across different environments. This has led to the rise of container orchestration solutions.

Container orchestration is the process of automating operations such as deployment, administration, scaling, load balancing, and networking, which containerized workloads require to run. All this occurs at scale across multiple nodes, known as clusters, allowing an application to be deployed across different environments without interruptions.

Kubernetes, otherwise known as K8s, is an open-source, scalable container orchestration framework that uses an API to automate the process of running applications across a network and tackle the complexities that arise from it. Google developed it and, in 2015, open-sourced it to the Cloud Native Computing Foundation.

You build Kubernetes resources declaratively. First, you define all the requirements in a YAML configuration file. To deploy a container, Kubernetes locates the best host (a machine that hosts a node) that meets all the requirements in the Manifest.yml file. Then, it automatically schedules the cluster deployment to that node. Kubernetes also manages the container’s lifecycle based on the defined configurations.

The Kubernetes framework uses the following key components to deliver container orchestration:

• Node — A worker machine to which Kubernetes deploys containers
• Cluster — A group of connected nodes. Having multiple nodes helps balance workloads, ensuring the application runs even if a node fails.
• Kubelet — An agent that runs on every node and ensures that the containers are running as expected
• Control Plane — A collection of processes tasked with controlling all the operations
• Pod — An object that encapsulates the containers deployed on a node. A pod is essentially an application instance and is the smallest object you can create in Kubernetes.

Kubernetes is an excellent option for organizations that need to deploy and manage large numbers of containers. Managing the lifecycle of containers with orchestration tools benefits DevOps teams, who integrate them into continuous integration/continuous development workflows.

Docker Swarm

Docker Swarm is Docker’s native open-source container orchestration solution and an alternative to Kubernetes. It offers scaling, multi-host networking, automatic load balancing, and all other features required for mass container deployment and administration — without depending on a third-party orchestration tool. It has a straightforward installation process, is lightweight, and is easy to integrate if you’re already accustomed to the Docker ecosystem.

Docker Swarm is a great option when working with a few nodes and relatively simple applications. However, if you’re orchestrating large nodes for critical applications, you would benefit more from Kubernetes’s security features, constant monitoring, flexibility, and resilience.

Docker vs Kubernetes

It’s apparent by now that Docker and Kubernetes have different use cases. You use Docker for packaging and shipping applications and working with a single node. Meanwhile, Kubernetes deploys and scales applications across a cluster of nodes. Furthermore, Kubernetes only manages containers, requiring separate software to build them.

However, while Kubernetes and Docker are distinct, they share the goal of delivering scalable containerized applications. They’re neither competitors nor mutually exclusive. They make the perfect team.

Docker and Kubernetes

Docker ships and deploys applications on a single node, and Kubernetes manages applications across a cluster of nodes. When deployed together, Docker and Kubernetes can benefit from each other, giving applications scalability, agility, and resiliency.

Kubernetes can make Docker containers more resilient by tracking the state of each node in a cluster. It automatically restarts, replaces failed nodes, and kills unresponsive nodes that don’t pass health checks. Load balancing further ensures that the nodes aren’t overworked.

Kubernetes and Docker also offer a rich set of functionalities that help determine how different application components will run. This makes it easy to update your application at will. Furthermore, scaling is seamless, as you can create Docker containers quickly, and Kubernetes can scale clusters with minimal manual intervention.

Other benefits include:

• Optimal resource usage
• Software health monitoring
• Automated operations like automated deployment and self-healing
• Storage orchestration

Furthermore, Docker containers are system-independent and can run on any environment that supports the Docker Engine, making migration hassle-free.

There are no limits to what you can achieve by strategically integrating Docker and Kubernetes. Both are powerful technologies that can accomplish a wide range of tasks. This dynamic duo has seen great success in serverless computing, multi-cloud deployment, microservices administration, and machine learning.

Together, Docker and Kubernetes are the best way to build an adaptable and efficient software development environment. Docker ensures that your applications are fast and system-agnostic, while Kubernetes ensures they have the maximum uptime, proper load balancing, and ability to scale the cluster at will.

Kinsta’s feature-packed, high-performance cloud platform includes Kubernetes for maximum scalability.