Docker vs Kubernetes: The Complete Guide

What are the differences of Docker vs Kubernetes? This is a common question with a not-so-simple answer. The reality is that Docker is a company with multiple different products (container technology, and container scheduling technology called Swarm) and Kubernetes is a container scheduling and orchestration technology. So in this article we’re going to explore a more meaningful question… What are the differences between Docker Swarm (which we will simply refer to as Docker for the remainder of this article) and Kubernetes.

With the rise in Kubernetes (also known as K8s) and the recent announcement around Mirantis acquiring Docker Enterprise, which bundles both Docker Swarm and Kubernetes into a managed solution for enterprises wishing to adopt container workloads, this is the perfect time to discuss the key differences between the two products. To be clear Docker Swarm is part of Docker Enterprise which is now owned by Mirantis.

Docker and Kubernetes are both usually tasked with managing the lifecycle of distributed application workloads within containers. This typically includes ensuring workloads are running, healthy, and accessible. While there are similarities in the mechanisms, these two technologies solve these challenges in very different ways.

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How many organizations are using Docker vs Kubernetes?

There are no hard numbers published giving insight into how many Docker or Kubernetes installations are running production workloads. Given the recent sale of Docker Enterprise, we know there are several hundred customers using that platform, and there is still activity and interest in the Docker community slack channel. We also know that several of Instana’s customers orchestrate their workloads using Docker as well. That being said, there are many more who operate other platforms such as Kubernetes, Mesos, Nomad, and Pivotal Platform (formerly Pivotal Cloud Foundry). If you’re reading this article, you may be trying to decide which technology to use, or perhaps you’re just curious why people are holding onto Docker when there is a hugely popular project in Kubernetes that addresses many of the same use cases and more. If Google Trends are any indication, Kubernetes is vastly more popular than any other container orchestration platform today.

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What are the similarities of Docker vs Kubernetes?

For teams running multiple containerized workloads, both Kubernetes and Docker enable them to define a desired state. Essentially Docker or Kubernetes will orchestrate the needs of your system. Both Docker and Kubernetes are backed by distributed key-value stores which ensure resilience in the event that a scheduler node is disrupted. They both expose APIs which are secure, and accept configuration for the workloads they run as declarative templates. Docker and Kubernetes can run anywhere, so the use of either solution will not lock you into a single vendor or cloud platform. There are more similarities but these are some of the most important comparisons.

Docker vs Kubernetes: What are the differences?

Kubernetes trades off operational simplicity for a highly extensible API, which includes support for additional workload types. Docker maintains a fairly static API and network configuration approach which is suitable for many early startup use cases. Kubernetes has also gathered the support of the community at large, created a huge ecosystem of plugins, tools, and technologies around it – which is a double-edged sword. 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.

Is Docker Dead?

The technology Mirantis purchased from Docker included Swarm + SwarmKit, but those were tied to the Enterprise version of the product and is quite likely a fork that was upstreamed by the Open Source repositories that are still owned by Docker. While Mirantis has announced they will support Swarm for the near-term future (since many of Docker Enterprise customers still use the product) it’s unclear whether any features, fixes, or patches will make it upstream to the open-source version. It’s also unclear whether or not Docker will continue development on Swarm + Swarmkit.
I personally prefer the simplicity and administration of Docker vs Kubernetes. I’ve used Docker to manage workloads that handle over 40 million transactions in a day. Given the uncertainty around the future of Docker and support for it, I will be moving the workloads I manage on Docker to Kubernetes in the near future. For those who are looking for a simpler way to manage container workloads, I don’t have a good answer for you.

What’s next in the Docker vs Kubernetes battle?

Hopefully, some of the lighter weight Kubernetes distributions being developed, which reduce some of the cognitive and operational complexity such as Rancher’s K3S, will become suitable for production workloads over the next year. Every major cloud provider offers Kubernetes today and will continue investing in simplifying the management, usage, and life cycle of those products so long as there are consumers of the technology. There is no easy answer to the challenge of managing the complexity of distributed applications, but there are ways to help you gain optics and understanding of how those environments impact your application.

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Instana screenshot showing Kubernetes monitoring dashboard.

 

Instana offers uncontested visibility into Kubernetes environments, helping you understand not only how Kubernetes is performing, but the performance of your underlying application as well. Of course Instana also works with Docker but we’ve seen the future and Kubernetes appears to be the clear winner in the container scheduler and orchestration wars. You can learn more about how Instana monitors Kubernetes in my most recent webinar and if you’re already running Kubernetes today, check out our free trial.

Watch the following video to see how quickly and easily you can monitor Kubernetes, Docker containers, and all of your application services.

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