What is difference between Docker-Machine and Docker Engine?https://docs.docker.com/machine/overview/

• 1. Docker Engine runs on Linux. If you are not running natively on Linux, Docker-Machine gives your a lightweight Linux VM to serve as Docker_Host. Docker Engine and containers reside INSIDE the Docker_Host.
  2. If you have a Linux box as your primary system, and want to run docker commands, all you need to do is download and install Docker Engine. However, if you want an efficient way to provision multiple Docker hosts on a network, in the cloud or even locally, you need Docker Machine.
  3. Whether your primary system is Mac, Windows, or Linux, you can install Docker Machine on it and use docker-machine commands to provision and manage large numbers of Docker hosts. It automatically creates hosts, installs Docker Engine on them, then configures the docker clients. Each managed host (“machine”) is the combination of a Docker host and a configured client.
  4. When people say “Docker” they typically mean Docker Engine, the client-server application made up of the Docker daemon, commands (via APIs) for interacting with the daemon, and a command line interface (CLI) client that talks to the daemon (through the REST API wrapper). Docker Engine accepts docker commands from the CLI, such as docker run <image>, docker ps to list running containers, docker images to list images, and so on.
  5. Comments from Udemy Instructor James Lee
     1. Multiple hosts means multiple VMs.
     2. Each docker machine is effectively a VM.
     3. Docker_Host points to the IP of your active VM.
     4. If you look at the droplets section under your digital ocean account, you should see multiple droplets, each droplet is a an individual VM.
     5. So yes Digital Ocean creates different hosts for you and docker-machines run on multiple hosts on Digital Ocean. So we need a swam manager to manage all the hosts which will operate transparently to the end users. This is the whole point of Docker Swarm.