An absolute difference between Kubernetes and Docker is that Kubernetes is indicated to run across a bunch while Docker runs on a single node. Kubernetes is vaster than Docker Swarm and is implied to coordinate clusters of nodes at scale in production in an efficient way.

Kubernetes is belittling Docker as a container runtime after version 1.20. Docker as an underlying runtime is being depreciated in favor of runtimes that utilize the Container Runtime Interface (CRI) designed for Kubernetes. If you are an end-user of Kubernetes, it will not fetch you much change.

Kubernetes is most typically used with Docker, though it can also be employed with any container runtime. RunC, cri-o, containerd are other container runtimes that you can deploy with Kubernetes.