ECCB 2014 tutorial T01 - Using RSAT with a Docker Virtual Environment (VE)

To run docker under Mac OSX, you must first run the program boot2docker.

Starting docker on Mac OSX

1. boot2docker start

   Important: when starting, boot2docker will display an message indicating the local IP of your docker host.

   2014/08/12 09:43:36 Waiting for VM to be started...
   .......
   2014/08/12 09:43:58 Started.
   2014/08/12 09:43:58   Trying to get IP one more time
   2014/08/12 09:43:58 To connect the Docker client to the Docker daemon, please set:
   2014/08/12 09:43:58     export DOCKER_HOST=tcp://192.168.59.103:2375

2. Before running docker, you must export the corresponding environment variable. Type the following command in the terminal (replace [...] by the actual address reported by boot2docker).

   export DOCKER_HOST=tcp://192.168.59.103:2375

   Tip:You can always obtain the IP address of your boot2docker host with the following command:

   boot2docker ip

   Connect to the shared folder using Finder (OS X).
   Connect to cifs://192.168.59.103/data
   Once mounted, will appear as /Volumes/data

Folder sharing

3. In order to use the "build" function in docker, you also need to perform one step: ensuring the fodler sharing (see https://github.com/boot2docker/boot2docker#folder-sharing

# Make a volume container (only need to do this once)
docker run -v /data --name my-data busybox true

# Share it using Samba (Windows file sharing)
docker run --rm -v /usr/local/bin/docker:/docker -v /var/run/docker.sock:/docker.sock svendowideit/samba my-data

# then find out the IP address of your Boot2Docker host
boot2docker ip
## Should return something like this:    192.168.59.103
	

1. Check that docker is installed on your machine

   docker version

2. Get the list of docker commands

   docker

3. Docker's "Hello world" test
   Test the following command to check that docker is working fine.

   docker run hello-world

4. Running a command in an Ubuntu 12.04 shell
   The following command will download (if required) an image of Ubuntu 12.04, and run a simple command in it.

   docker run ubuntu:12.04 echo "Hello world"

   The first time you run ubuntu:12.04, docker will download the image (this can take a few minutes, depending on the speed of your Internet connection). The next calls tu ubuntu:12.04 will immediately launch the local image, and you will be able to instantly execute any command under Ubuntu 12.04, as you will notice by typing the command again.

   docker run ubuntu:12.04 echo "Hello world again"

Docker allows you to run alternative distributions of Linux (for example Ubuntu, Centos, ...), or alternative versions of a given distribution (for example Ubuntu 14.04 and 12.04). This is particularly convenient for checking software portability.

In the previous example, we choose Ubuntu 12.04 because it occupies less space (108Mb) than the current Ubuntu release (14.04 in August 2014). If you dispose of a fast connection and are not too limited in hard drive space, you can re-run the command above replacing ubuntu:12.04 by ubuntu:14.04. This will require to tranfer 225.4Mb from the docker image repository, and to occupy the same space on your hard drive.

5. Getting the list of docker images
   To obtain a list of all the docker images running on your machine, type

   docker images

   REPOSITORY          TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
   ubuntu              14.04               c4ff7513909d        34 hours ago        225.4 MB
   ubuntu              12.04               822a01ae9a15        34 hours ago        108.1 MB
   hello-world         latest              565a9d68a73f        4 weeks ago         922 B
   

6. Removing docker images
   Docker images and containers occupy a relatively important space on your hard drive, so after having played around with docker, you will probably like to remove images you don't intend to use anymore.

   However, docker will not allow you to remove an image as long as there are still some containers depending on it (for the difference betwen image and container, see here). We will thus proceed in the following order:

   1. List the containers depending on the image we want to suppress (for example hello-world)

      docker ps -as

   2. Identify those depending on the image to be suppressed

      docker ps -as | grep hello-world

   3. Remove these containers

      docker rm  $(docker ps -as | grep hello | awk '{print $1}')

   4. Identify the image we want to delete

      docker images | grep hello-world

   5. Remove this image

      docker images | grep hello-world | awk '{print $3}' | xargs docker rmi

   Exercise: apply the same protocol to delete the ubuntu:14.04 image (assuming you did run it, and you don't need it anymore).