Docker and Kubernetes are two of the best containerization options on the market if you’re a developer or a system administrator. However, they have unique technologies targeting different types of applications. Understanding these differences is key to choosing the right technology for your project.
In a nutshell, Docker can be a better option for small-scale applications, whereas Kubernetes shines in scaling. You can use Kubernetes to automate deployment for new containers, enabling applications to scale as needed.
In this post, we’ll take a closer look at Docker and Kubernetes. We’ll go over the pros and cons of using each technology and discuss specific use cases to help you make a decision. Let’s get to it!
An Introduction to Docker and Kubernetes
In programming, containers are packages that can encapsulate applications and all their dependencies, libraries, configuration files, and everything else required for them to run.
Containers are designed to be lightweight, so they can be shared easily. This makes it much more straightforward for teams to collaborate on development using identical environments.
Containers are not unique to either Docker or Kubernetes. However, both solutions are designed around containers.
Docker is a solution for developing, shipping, and running applications in isolated containers. It’s software that enables you to create consistent container environments for applications and share configurations in easy-to-port text files (Dockerfiles):
Docker has become a ubiquitous tool in development work. Developers use it for working on projects and testing software. It integrates with Continuous Integration (CI) and Continuous Deployment (CD) workflows, and it works with most cloud providers.
Kubernetes (or K8s) is an open-source solution designed to help you coordinate and automate the deployment and scaling of containers. This means you can use Kubernetes to deploy infrastructures that can handle hundreds of thousands of requests and make short work of it:
As you can see, Docker and Kubernetes aren’t designed to solve the same problems. Docker is a container creation and management solution, while Kubernetes or K8s is about orchestrating containers at scale. They’re complementary tools – many developers use Docker to build their container images and Kubernetes to run them at scale.
Kubernetes was created by Google and is maintained by the Cloud Native Computing Foundation (CNCF). It’s also the backbone of the Cloudways Autonomous managed WordPress hosting service:
Cloudways Autonomous was created with growing businesses in mind. It’s designed to scale seamlessly with your website as it grows. It can handle large spikes in traffic autonomously and offers a fully hands-off server management experience.
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The Pros and Cons of Using Docker
Docker is not the only containerization solution on the market. There are several other options, such as containerd (now the default runtime for Kubernetes), Podman, LXC/LXD, Buildah, and more.
However, it’s one of the most widely used solutions. It’s popular for small and medium-scale applications in large-scale production environments, DevOps workflows, and microservice architectures.
Some of the main benefits of using Docker include:
- Easy setup. Docker containers are remarkably straightforward to set up and deploy. You can launch Docker containers in minutes from the terminal. Plus, you can download public container images from the web, enabling you to reproduce highly popular development environments.
- Highly portable environments. Docker containers are easy to reproduce. You can share Dockerfile text files that others can use to deploy the same container setup that you’re using. This makes for identical development environments with easy setups. You can also set up repositories to share images.
- Isolated containers. Docker isolates containers using Linux kernel features like namespaces and cgroups, allowing you to run multiple projects securely on one device.
- Great for version control. You can manage and store application versions with different Docker images. This enables you to reproduce entire environments from previous versions.
- Flexible storage options. Docker supports various storage options through volume plugins, including local storage, network-attached storage, and cloud storage solutions.
- Lightweight system resource usage. You can deploy and run multiple Docker containers in a single system. They’re more lightweight than traditional Virtual Machines (VM), but they still consume resources. Even so, using containers will give you far better returns in terms of system performance.
- Massive community. Docker is a popular platform. Users share extensions, documentation, and container images, and collaborate on open-source Docker projects.
The main downside of using Docker is that it can become difficult to manage for large-scale applications. Docker offers networking functionality such as bridge and overlay networks, which enable you to connect containers. However, that functionality doesn’t always scale too well.
There’s a feature in Docker called Swarm mode, which is used for container orchestration at scale. That’s similar to what Kubernetes does, although the latter is much more popular in the world of large-scale deployments.
The Pros and Cons of Using Kubernetes
Kubernetes is the standard when it comes to container orchestration. It’s the most popular solution for deploying and managing containers at scale.
There are some alternatives to Kubernetes, such as Nomad, Cycle.io, Docker Swarm, and OpenShift. However, it’s fair to say there are far more reasons to use Kubernetes than any of those alternatives (barring specific use cases).
Let’s go over those reasons:
- Designed for large-scale applications. Kubernetes is what you want if you need to automate the deployment, scaling, and management of containers at scale. It implements load balancing and scaling automatically.
- Dynamic container adjustment. By using horizontal scaling, Kubernetes can automatically deploy containers to adjust resources based on the website’s demand.
- Automatic management for container failure. If a container fails, K8s can take it offline and replace it, all while maintaining high availability. If entire nodes fail, Kubernetes can reschedule the deployment of containers at scale.
- Automated rollouts and rollbacks. You can use Kubernetes to roll out changes to applications progressively. If something goes wrong, you can roll back the change without it affecting the application.
- Great for hybrid environments. Kubernetes shines in hybrid environments, such as combinations of on-premises hardware and cloud infrastructure. It can also enable containers to work across cloud providers.
- Multiple storage options. Kubernetes works with local, network, cloud storage, and object storage solutions, among other options. That means you can manage storage using one or more solutions such as Amazon S3 and Google Cloud Storage.
- Massive community around the software. Since Kubernetes is so popular, you can find comprehensive documentation on how to use the system. Moreover, you’ll be able to troubleshoot with other users in the community.
While Kubernetes is the standard for container orchestration, the system is not without downsides. Docker is, by far, a more user-friendly solution, even if it’s not designed for the same kinds of applications and use cases as Kubernetes.
There’s a significant learning curve to using Kubernetes. Managing large-scale Kubernetes deployments can require a lot of work and a sizable team.
If you don’t fully leverage its automation functionality, using Kubernetes can be challenging.
That’s one of the reasons why it makes sense to use Cloudways Autonomous managed WordPress hosting. With our Cloudways Autonomous plans, you get all the advantages of a platform that leverages Kubernetes, without the downside of having to manage large numbers of containers.
When to Use Docker vs Kubernetes for Your Applications
Docker is a container creation, management, and deployment solution. With Docker, you’re unlikely to be dealing with massive numbers of containers for a single application. That’s Kubernetes territory. However, you can use Docker for some level of container orchestration (with Docker Compose or Swarm mode).
Kubernetes doesn’t focus on individual container creation. It’s a system for managing containers at scale. Using Kubernetes you can deploy and manage large numbers of containers quickly.
Kubernetes also heavily emphasizes automatization. With the proper setup (which can be challenging to configure), you can mostly automate Kubernetes deployment and management.
To put those differences into perspective, let’s go over some common use cases for Docker:
- For setting up local development environments. Docker’s lightweight isolated containers make it a fantastic solution for setting up local development environments.
- CI and CD pipelines. You can easily integrate Docker in CI/CD pipelines to build, test, and deploy applications.
- Reproducible testing. The portability of Docker images makes them perfect for sharing testing environments across teams.
Now let’s look at some use cases for Kubernetes:
- High-availability applications. If you run web applications that need near-perfect availability at scale, Kubernetes is the obvious solution.
- Multi-cloud or hybrid deployments. Kubernetes enables you to deploy applications across multiple cloud providers and local infrastructure.
- Auto-scaling applications. Kubernetes can leverage automatic horizontal scaling to deploy containers to handle large amounts of traffic quickly. It can also manage load balancing, employ self-healing, and automate update rollouts (and rollbacks).
Kubernetes and Docker are not at odds in most cases. In fact, they work together effectively in modern deployments, and that’s what a lot of large-scale projects do.
Developers typically use Docker for building and testing container images locally, which are then deployed to Kubernetes clusters.
While Kubernetes previously used Docker’s runtime to run containers, it now uses containerd (which was originally part of Docker) as its default container runtime.
This technical change doesn’t affect most users – Docker-built images continue to work perfectly on Kubernetes clusters, maintaining the complementary relationship between these tools. It’s truly a match made in developer heaven.
If you’re interested in a solution that combines Kubernetes with managed WordPress hosting, take a look at Cloudways Autonomous. It offers the best parts of using Kubernetes without the worst ones (doing all of the server management work).
Conclusion
Docker is a solid containerization option for simple projects or small websites. However, it struggles in terms of scalability. This can ultimately hinder your website when it starts to grow and get major surges in traffic.
Kubernetes is better suited for applications and websites of a large scale. The technology is designed to help you scale applications with a high degree of automation and availability. Kubernetes can also self-heal containers, making it nearly impossible for your site to go down with the right setup.
If you want to host your WordPress website on a platform that leverages Kubernetes, check out Cloudways Autonomous. This managed WordPress hosting service offers auto-scaling and high availability. Get started today!
Sandhya Goswami
Sandhya is a contributing author at Cloudways, specializing in content promotion and performance analysis. With a strong analytical approach and a keen ability to leverage data-driven insights, Sandhya excels in measuring the success of organic marketing initiatives.
