Kubernetes and Docker are two of the most popular container orchestration and building platforms on the market. Many professionals working with cloud-native technologies wonder whether it’s a conversation between whether they should use Kubernetes vs Docker or if they should use both in conjunction.
Docker provides tools for sharing, creating, and packaging containers on a single node to create a quicker and easier delivery process for developers. Kubernetes works to eliminate manual scaling and deployment operations by running these packaged containers across a cluster.
To summarize, Docker creates and packages the containers, while Kubernetes is a container orchestration platform that runs them at scale. You can use Kubernetes and Docker separately, but many software developers choose to use them together because they accomplish separate tasks.
The organization Docker has many different tools for developers, but their container orchestration tool is called Docker Swarm. With this in mind, we shall be using Docker and Docker Swarm interchangeably throughout this guide. Now let’s deep dive into the difference between Docker and Kubernetes.
What is Docker?
Docker Inc. is an organization that publishes both open source and proprietary tools for developers. These tools include a container runtime (containerd) and a container orchestration tool called Docker Swarm. While containerd can be used alongside Kubernetes, Docker Swarm is a more direct alternative to Kubernetes.
Docker also provides tools for creating, sharing, and running containerized applications. The toolset allows developers to separate their application into containers. Separating your application from your infrastructure simplifies the delivery process and enables developers to deliver software quickly.
Containers have become increasingly popular as more organizations shift to hybrid multi-cloud and cloud-native environments. Without Docker, you can still create containers, but the platform makes the process easier by reducing the lag time between writing code and running it in production. Docker uses simple language and automation to seamlessly send, build, and run containers through a single API.
Here are the three main features that DevOp professionals are taking advantage of when using the Docker platform:
- Building Container Images: Package, build, and run container images by utilizing Docker Compose and Docker Build. Integrate development tools such as VS Code, CircleCI, and GitHub throughout the developmental pipeline.
- Sharing Images: Easily share container images with Docker Hub access across your organization or team.
- Running Containers: Deliver and run multiple applications across all of your environments. Independently deploy containers in different languages to reduce the risk of mistakes from miscommunication. This process is completed through Docker Engine.
In 2022, the term Docker is often used as a shorthand for containerization in general across software professionals, whether they use the platform or not.
Docker Benefits
Image Statistic Source: Gartner Report
There are many benefits to using containerization. While there are alternatives to docker for containerization, none are as popular or as widely supported (yet).
Running apps through containers can help improve performance, speeds up delivery time, and allows you to run containers in most environments. This section will deep dive into the top reasons you should use Docker’s capabilities for your next project.
The first benefit is that Docker is lightweight and portable. Docker contains everything you need for your application to run effectively and increase functionality. The portability makes it easy for your application to move between different environments because you can run containers wherever you want.
Next, Docker containers are independent of one another, making it possible to use different software versions for different containers. Independent testing across your containers ensures that the images you create will perform correctly. Isolation also improves security since each container runs on its own namespace. Lastly, containers help make your application more agile and increase CI/CD development efficiency. Enhancing your continuous integration and delivery enables you to deliver software developments faster.
Docker Drawbacks
Although there are many benefits to utilizing containerization, there are also some important drawbacks to consider.
Many developers bring up frustration over the fact that file storage gets deleted any time the container gets recreated. Containers are recreated very frequently – especially when scaling is automated. Docker Data Volumes help create more persistent storage, but it is still a point of contention for developers. The main drawback is that it requires more planning and configuration than would be required in a traditional VM.
Another downside to using Docker is that containers primarily benefit microservices-based applications making them less useful for monolithic development. If you have the latter type of application, then the benefits of Docker may be outweighed by the additional layer of abstraction.Finally, Docker containers add additional layers, which requires additional computational resources and performance overhead time. If you want to eliminate this extra overhead requirement, you’ll need to run your application directly on a bare-metal platform.
What is Kubernetes?
At its most basic level, Kubernetes is the operating system of containerized applications and the cloud. Kubernetes is another open-source orchestration platform that manages, scales, and automates workloads for containerized applications. Since Kubernetes is often called K8s, we will use these terms interchangeably throughout this guide.
Docker Swarm and Kubernetes are both container orchestration tools. However, many DevOps professionals prefer Kubernetes because it eliminates several manual deployments and scaling operations. It also allows for more flexibility throughout the container orchestration process as your application continues to grow.
According to the Cloud Native Computing Foundation, 96% of organizations are either using or evaluating Kubernetes. This has benefited Kubernetes users by creating a broad range of management support platforms to pop up on the market in recent years. The most popular Kubernetes management services include Microsoft Azure Kubernetes Service, Google Kubernetes Platform, IBM Cloud Kubernetes Services, and Amazon Elastic Kubernetes Service.
K8s automatically fixes and restarts containers if errors arise. Developers can use this platform to manage container clusters easily because you can tell Kubernetes where to allocate resources before a problem occurs. It then takes this information and uses self-healing technology to fix your application’s containers.
Kubernetes Benefits
Now that you understand what Kubernetes is, let’s deep dive into the top benefits your organization can expect to gain from adopting its tools.
Kubernetes reduces timeframes and simplifies the shipping, development, and release process. This is especially useful for applications that have infrastructures broken down into microservices. In this case, you can break down your functional units into smaller groups to have them each specialize in a single feature.
Another major benefit of using Kubernetes is that it is easy to scale in hybrid and multi-cloud environments. The scalability makes it an excellent choice if you work for a large organization because it can host workloads across multiple or a single cloud. Large cloud providers have almost all adopted some kind of “Kubernetes as a service” — the same cannot be said for Docker Swarm or other orchestration tools.
Kubernetes Drawbacks
Of course, even with so many positives, every container platform will also have some negatives to consider. Overall, if you are using containers in production, you should be using Kubernetes despite any drawbacks. However, we have included some drawbacks below that you should be aware of when utilizing this resource.
The K8s platform also requires a lot of training, updates, and maintenance over time when managing multiple clusters. The extra manual support can become a time-consuming task for your DevOps team, even with the automation features.
Additionally, troubleshooting can be made more difficult by the ephemeral nature of Kubernetes pods — what do you do when you track down an issue to a pod that has since been destroyed by an autoscaling policy?
While Kubernetes can automatically scale out your services for you, it lacks basic analytical tools and does not include any built-in log storage mechanisms. When using Kubernetes, you will want to use an external log aggregation tool at a bare minimum.
Kubernetes is typically best for complex and enterprise-scale development projects and can be overkill if you’re working on something of a smaller scale. If you don’t need the additional scaling and resiliency of Kubernetes, using it may not be worth the additional cost and complexity.
What’s The Difference Between Kubernetes and Docker Swarm?
Kubernetes trades off operational simplicity for a highly extensible API, which includes support for additional workload types. Docker Swarm maintains a fairly static API and network configuration approach, which is suitable for many early startup use cases.
Kubernetes has gained widespread community and enterprise support. Its support amongst cloud providers makes it an excellent choice for hybrid- or multi-cloud deployments.
Kubernetes can seem daunting to small teams of engineers who simply want to translate the experience of working on their applications locally with Docker containers to the cloud. The differences mostly boil down to the simplicity of Docker with limited use cases, vs. Kubernetes ability to handle nearly all use cases but with significantly higher complexity.
Simplified Application Management With Docker, Kubernetes, and Instana
The distributed nature of containerized applications means that our old troubleshooting strategies won’t work anymore. Kubernetes and Docker can allow for additional resiliency, but they also introduce new failure points which may be obfuscated by the abstraction.
When an error occurs, we want to answer the questions “where?” and “why?” as quickly as possible. An observability platform can help with this. The right observability platform can act as an always-up-to-date map of your ever-changing application landscape.
Instana simplifies the management of your application by providing you with an infrastructure map that can be filtered and sorted by host, zone, or any other metadata. From this infrastructure overview, you can drill down through all of the layers: cluster, pod, container, all the way to the application runtime.
Remember the challenges with logging in Kubernetes? Instana doesn’t stop at just aggregating all of your logs. Because Instana understands every layer of your services, all logs are correlated with the relevant request, service, and host; this allows you to identify root causes with full context.
