Kubernetes question

richardfranco

Hello, I am pretty new in Kubernetes/Docker. One week ago or so, Kubernetes gave the news they will stop shipping dockershim with Kubelet, thus dropping their support for Docker altogether by late 2021. What do you think about it? What happen with the deployments currently using docker?... they will have to move to others like Containerd, CRI-O? What would be the impact?

chrispokorni

Hi @richardfranco,

You are correct, Kubernetes did announce they will discontinue support for the dockershim, the interface that allows Kubernetes to interact with the Docker container platform. The same topic is covered by more than a dozen articles on the web, headlining that Kubernetes will no longer support Docker. However, the same articles are explaining why this is not such a big deal, as it will not adversely impact anyone, and business will go on as usual.

You can also read through the Docker, Containerd, and Runc documentations, blogs, and especially this blog post that summarizes all the information you may need on the topic. But, here's the skinny: Docker, although it is often referred to as a container runtime, is not a runtime. It is a rich set of user-friendly tools built on top a container daemon - Containerd. At the core of Containerd is Runc, the actual container runtime.

Therefore today's Docker containers are already running on Containerd, and they will keep running on it in the future as well, because especially now I do not see Docker deciding to move away from Containerd and Runc as its container runtime.

CRI-O is also able to run Docker containers, being another implementation of the Open Container Initiative (OCI) standard, just like the Runc/Containerd/Docker stack.

As far as the future of dockershim, it may live on if its development will be taken over by Mirantis, the company that recently acquired Docker Enterprise.

Regards,
-Chris