Run docker from within toolbox

Question

Within Google Container OS, I would like to use it as my cloud development environment. How would I run the docker command from the toolbox? Do I need to add the docker.sock as a bind mount? I need to be able to run docker (and docker-compose) to run my development environment.

Answer 1

Google Container OS images come with docker already installed and configured, so you will be able to use the docker command from the command line without any prior configuration if you create a virtual machine from one of these images, and SSH into the machine.

As for docker-compose, this doesn't come pre-installed. However, you can install this, and other relevant tools/programs you require by making use of the toolbox you mentioned which provides a shell (including a package manager)in a Debian chroot-like environment (here you automatically gain root privileges).

You can install docker-compose by following these steps:

1) If you havn't already, enter the toolbox environment by running /usr/bin/toolbox

2) Check the latest version of docker-compose here.

3) You can run the following to retrieve and install docker-compose on the machine (substitute the docker-compose version number for the latest version you retrieved in step 2):

curl -L https://github.com/docker/compose/releases/download/1.18.0/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose

You've probably found at this point that although you can now run the freshly installed docker-compose command within the toolbox, you can't run the docker command. This is because by default the toolbox environment doesn't have access to all paths with the rootfs and that the filesystem available doesn't correspond between both environments.

It may be possible to remedy this by exiting out of the toolbox shell, and then edit the /etc/default/toolbox file which allows you to configure the toolbox settings. This would allow you to provide access to the docker binary file in the standard environment by following these steps:

1) Ensure you are no longer in the toolbox shell, then run command which docker. You will see something similar to /usr/bin/docker.

2) Open file /etc/default/toolbox

3) The TOOLBOX_BIND line specifies the paths from rootfs to be made available inside the toolbox environment. To ensure docker is available inside the toolbox environment, you could try adding an entry to the TOOLBOX_BIND section, for example --bind=/usr/bin/docker:/usr/bin/docker.

However, I've found that even though it's possible to edit the /etc/default/toolbox to make the docker binary file available in the toolbox environment, when certain docker commands are run in the toolbox environment, additional errors are generated as the docker version that comes pre-installed on the machine is configured to use certain configuration files and directories and although it may be possible edit the /etc/default/toolbox file and make all of the required locations accessible from within the toolbox environment, it may be simpler to install docker within the toolbox by following the instructions for installing docker on debian found here.

You would then be able, to issue both the docker and docker-compose commands from within toolbox.

Alternatively, it's possible to simply install docker and docker-compose on a standard VM (i.e. without necessarily using a Google Container OS machine type) although the suitability of this depends on your use case.