The difference being that Google has deprecated the shimming to Docker they had been doing with the “Docker” runtime to access containerd, so now it will go straight to the source by default.
Red Hat OpenShift also switched from using Docker as its runtime with OpenShift 4 in 2019, though it was in favor of CRI-O rather than containerd.
All accurate. My point is that Kub deprecating the shimming does not affect Docker’s popularly or market share either way. The existence of the shim was an implementation detail and Docker themselves have been encouraging the switch to containerd. They clearly want the Docker brand to be attached to developer-facing tools instead of a hidden piece of increasingly commoditized infrastructure.
If a critical mass of kubernetes deployments switched from containerd to cri-o, that would be more problematic for Docker, but that seems unlikely to happen. Openshift to my knowledge is the only major kubernetes distribution not based on containerd. At this stage of the adoption cycle, cri-o is unlikely to be more than a distant second to containerd.
Yes, and I did not mean to diminish that context, more so expand upon the "k8s not using Docker" side of things from the parent you were responding to.
Red Hat OpenShift also switched from using Docker as its runtime with OpenShift 4 in 2019, though it was in favor of CRI-O rather than containerd.