After research about docker swarm. I know more deeply about docker.
Before that i just install docker window, create image, run image on container. It 's a bit easy.
But i now i see docker machine which will host the docker engine. Docker machine may be hosted by virtual box, cloud host, and physical host (is it available for only Linux ? )
The question is what is docker machine when i just install docker desktop. And what is different from docker machine created by Hyper-V using docker-machine create -d hyperv vm