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Wait, Docker is deprecated in Kubernetes now? What do I do?

Kohei Ota on December 02, 2020

tl;dr For developers Don't panic, Docker containers and images are still alive. It's not that it will change everything. Als...

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MrViK • Dec 4 '20

Another OCI Runtime -> crun
It's faster than runc (the performance gains are notable when starting containers).
Also it supports cgroups v2, runc also added support on v1.0.0-93 (which has not been launched?)

podman + crun do work very well (also podman can launch rootless containers) so I prefer to use them instead of Docker + runc.

Tom • Dec 5 '20

I just moved to podman/crun due to cgroups problem
Docker phases out?

Kohei Ota • Dec 4 '20

Docker 20.10 will support cgroups v2

MrViK • Dec 4 '20

Will, in the future. Podman does it right now and rootless containers are a huge improvement on process isolation

Kohei Ota • Dec 5 '20

Docker also supports rootless now.

Jeff Triplett (he/him) • Dec 3 '20

PSA: This doesn't mean what most people think it means. kubernetes.io/blog/2020/12/02/dont...

Marc • Aug 26 '21

For dummies like me:

Your Kubernetes > v1.20 (or whatever) won't use the Docker container runtime BUT
Your Docker-built containers will still run in Kubernetes... but with a different container runtime (e.g. ContainerD)

TL/DR: The Docker Container Runtime is history - your Docker-built containers will still run.

Akito • Dec 9 '20

Just adding my 2 cents from my own experience.

At work, we are using classical RKE Rancher with Kubernetes with Docker and k3s Rancher with Kubernetes with containerd. So I have experience with both. The problem is, that in our case it often seemed like containerd, at least the way it is used with Kubernetes, is not that stable and reliable. It showed us a lot of bugs and issues, which the legacy Kubernetes never had shown.

So I'm asking myself, how can they suddenly guarantee that all this new stuff is even production ready, when we had not too many but quite substantial issues with it?

(Perhaps the issue was mainly to be found in the whole Rancher thing, but we cannot confirm this.)

kolaente • Dec 9 '20

Great overview, thanks!

Having more features while you never use, itself can be a security risk. The less features you have, the smaller the attack surface becomes.

I found this while very true kind of ironic since we're talking about kubernetes here which in itself is a very complex system. That does not invalidate the point you're making though, it just makes another case for why less complexity in an already complex system is probably a good idea.

starpebble • Dec 9 '20

Fantastic post. My feedback: I hope this particular Kubernetes rearchitecture saves us all time. We are getting closer to making it realistic to have a container format specific to my favorite programming language. No need for us to all be the same.

Andrew Malkov • Jan 10 '21

Both containerd and CRI-O know how to pull docker images and run them and Docker Images Manifest V2 and OCI image specification are almost the same, so we dont need to worry now.
But, if you want to know how to live without Docker I suggest you this video - How to live without Docker for developers - Part 1 | Migration from Docker to Buildah and Podman. Or just search Without Docker on YouTube.

Justin Refi • Jun 17 '21

So now I have to learn yet another framework (Buildah, Podman, etc) instead of just doing the easy thing and running Docker in Docker. The Kubernetes community sure loves creating new projects.