3 years ago

ubernetes is deprecating Docker as a container runtime after the v1.20 release. On a high-level, Kubernetes will show the deprecation message after upgrading the cluster to v1.20, and Kubernetes plans to remove Docker container runtime support as early as the v1.23 release.

Let us get back to the topic on why Kubernetes has deprecated Docker as a container runtime, Although Docker provides elements like UX, storage, networking and managing containers, Kubernetes only needs a container runtime to pull and unpack an image to an OCI bundle and invoke an OCI binary (low-level runtime) like runC to create and destroy containers.

There is still hope to use Docker as a Kubernetes runtime, as Mirantis and Docker are partnered to maintain the dockershim by taking it over from the Kubernetes.

For admins, if the Kubernetes clusters are setup on-premises with Docker, you need to replace it with the supported runtime and start learning to use the crictl CLI tool to inspect and debug container runtimes.