# Intro to Docker

## Installing Docker on OSX (using boot2docker)

Look at [Docker Installation](https://docs.docker.com/installation/mac/) or if you already have VirtualBox and Homebrew installed:

    `brew update && brew install docker`


## Running the Docker VM

Docker runs in a Linux VM on OSX. A Docker client runs on your host machine to control Docker containers in the VM. The `boot2docker` command controls that VM and provides information about it. You can issue the command without any arguments to see a list of available sub-commands.

    boot2docker
    
You can start the VM and set the appropriate `DOCKER_HOST` environment variable with:

    boot2docker up && $(boot2docker shellinit)

## What are Docker Containers?

Docker extends the functionality of lxc (linux containers). The improvements are best described here: [Stackoverflow: What does Docker add to just plain LXC](http://stackoverflow.com/questions/17989306/what-does-docker-add-to-just-plain-lxc)

## Using Docker Containers

Below are some example commands.

### See what sub-commands are available.

    docker
    
### Get help about the `run` command.

	docker run --help
	
### Run an Ubuntu container.

The default command for this container is bash. Once in there, run `top` to see what is running. Type `exit` and hit enter to quit the container.

    docker run -it --rm ubuntu
    
### Run a specific command in a container.

This will output the Ubuntu release information. When a container's command is finished it will stop automatically.

    docker run -it --rm ubuntu cat /etc/lsb-release
    
### Build an image (from a Dockerfile).

	mkdir docker-test
	cd docker-test
	echo 'FROM tutum/lamp:latest' > Dockerfile 
	docker build -t my-image .
	cd ..
	
### Run your new image in a container.

	docker run -d -p 8080:80 --name my-container my-image
	
### View your handywork.

Find your VM ip with:

	boot2docker ip
	
Now use this IP to access your container in a browser. Something like:

	http://192.168.59.103:8080

### Stop your container.

	docker stop	my-container
	docker rm my-container
	
or

	docker rm -f my-container
	
### Learn more.

[Docker User Guide](https://docs.docker.com/userguide/)