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Step 1: Update and Upgrade. Test the set up by running a hello-world container. Verify installation by checking the Docker version.There are container images. So what? It's not that big a deal.As Kelsey Hightower, Google Cloud Platform staff developer advocate and best-known teacher of all things Kubernetes, tweeted: " Docker != Containers. Here's what you need to know about it.Yes, the kubelet in the "dockershim" module, which implemented Container Runtime Interface (CRI) support for Docker, will soon be history. Docker is hotter than hot because it makes it possible to get far more apps running on the same old servers and it also makes it very easy to package and ship programs. A step by step tutorial about one of the easiest and most straight forward ways to have a simple single-node Kubernetes cluster running in your local using Docker Desktop (on Mac. This ensures you install the latest version of the.All that's happened is Docker as an underlying runtime is being deprecated in favor of CRI runtimes. You can still build containers, use them in registries, and push and pull. Docker can create them but Linux is still the boss."As the developers explained in their well-named " Don't Panic: Kubernetes and Docker" blog post, all that's happening is that Kubernetes is deprecating Docker as a container runtime after v1.20. There are container processes. There are container runtimes. Docker can push and pull from them.Developers just need to change their container runtime from Docker to a supported container runtime. "If it were, we wouldn't need the shim, and this wouldn't be a thing." But it's not the end of the world. The rest is only so much unneeded and unwelcome code, which opens a bigger attack surface and requires maintenance.In addition, Docker isn't compliant with CRI. Dockershim's job is to extract only the runtime. Docker is a popular choice for that runtime, but Docker was not designed to be embedded inside Kubernetes, and that causes problems.As the programmers observed, "The thing we call 'Docker' isn't actually one thing - it's an entire tech stack." Docker includes many user enhancements for programmers, but Kubernetes doesn't need any of that. Inside your Kubernetes cluster, the container runtime's job is pulling and running your container images.
![]() Kubernetes only leverages a fraction of what Docker is capable of at runtime. In fact, under the hood of both containerd and CRI-O, you'll find Docker's own open runtime, runc.As Hightower said in a later post, "Nothing changes. Today, the debate for which runtime to use is between containerd and CRI-O. Buildkit, our next generation build infrastructure, has a flexible architecture so that while it can be used as the builder with Docker, it can also talk directly to containerd or runc instead for use in infrastructure where Docker might not be available."Got that? Relax. The deprecation of docker-shim (and Docker Engine as runtime) marks the completion of a long-term commitment to provide a modern runtime for Kubernetes."Cao continued, "Container images you build using Docker tools will continue to run on Kubernetes. In a post, Dieu Cao, Docker's senior director of product management, explained, "If you're using Docker, you're already using containerd." In fact, "Docker created the containerd project, along with Google and IBM, in 2016, with the goal of this transition in mind. How you build and run them is up to you."Docker agrees. The container image is portable. The best image resizer for macThe Kubernetes crew will work closely with everyone to make sure we're all on the same page and that dockershim won't be put out to pasture until everyone is ready for the change. As the Dockershim Deprecation FAQ says, "The only thing changing in 1.20 is a single warning log printed at kubelet startup if using Docker as the runtime."Dockershim will stick around until the release of Kubernetes 1.23 in late 2021. The one and only thing that changes is you'll be using containerd or CRI-O to run them in Kubernetes. Odds are decent you're already doing that and you just didn't realize it.In any case, you're going to have lots of time to figure it out.
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