HOW DOCKER WORKS
Docker is a client-server application. The Docker server is a daemon that does all the heavy lifting: building and downloading images, starting and stopping containers, and the like. It exposes a REST API for remote management.
The Docker client is a command line program that communicates with the Docker server using the REST API. You will interact with Docker by using the client to send commands to the server.
The machine running the Docker server is called the Docker host. The host can be any machine—your laptop, a server in the Cloud™, etc—but, because Docker uses features only available to Linux, that machine must be running Linux (more specifically, the Linux kernel).
We’ll run the Docker client natively on OS X, but the Docker server will run inside our boot2docker VM. This also means boot2docker, not OS X, is the Docker host.
Step 3: Initialize and start boot2docker
First, we need to initialize boot2docker (we only have to do this once):
> boot2docker init 2014/08/21 13:49:33 Downloading boot2docker ISO image... [ ... ] 2014/08/21 13:49:50 Done. Type `boot2docker up` to start the VM.
Next, we can start up the VM. Do like it says:
> boot2docker up 2014/08/21 13:51:29 Waiting for VM to be started... ....... 2014/08/21 13:51:50 Started. 2014/08/21 13:51:51 Trying to get IP one more time 2014/08/21 13:51:51 To connect the Docker client to the Docker daemon, please set: 2014/08/21 13:51:51 export DOCKER_HOST=tcp://192.168.59.103:2375
Step 4: Set the DOCKER_HOST environment variable
The Docker client assumes the Docker host is the current machine. We need to tell it to use our boot2docker VM by setting the
> export DOCKER_HOST=tcp://192.168.59.103:2375