More about Docker

GLAMkit is Docker-compatible, and we recommend using Docker for development and deployment. Docker has many advantages over a simple Python virtualenv environment:

  • It eliminates the “works on my machine” problem by exactly reproducing an identical runtime environment everywhere.
  • It eliminates the need to install and run service dependencies directly on your OS, such as Elastic Search, PostgreSQL, Redis, etc.
  • It eliminates the need to install library dependencies directly on your OS, such as libjpeg, libtiff, etc.
  • It provides easy continuous deployment and rolling deployments on Docker Cloud via auto redeploy when a new image is built.
  • Much less (if any) downtime during deployments, because Node modules, Bower components and Python packages are already installed in the image.

Getting started

If you haven’t already, install Docker:

The typical Docker workflow is:

  • Define the image build instructions for each service with a Dockerfile.
  • Configure and manage a collection of services with a docker-compose.yml file.
  • During local development, mount your source directory into containers for rapid iteration without having to rebuild images.

Useful Docker commands

Here are some of the most commonly used Docker commands when getting started.

Rebuild images for all services in your compose file:

$ docker-compose build --pull

Start all services in your compose file:

$ docker-compose up

Stop all services in your compose file:

$ docker-compose stop

List all containers for services in your compose file:

$ docker-compose ps

Open a new shell ( inside an already running container for the django service:

$ docker-compose exec django

Remove all exited containers and their volumes:

docker rm -v $(docker ps -a -f status=exited -q)

Remove all dangling images (not tagged or used by any container):

docker rmi $(docker images -f dangling=true -q)

Remove all dangling volumes (not used by any container):

docker volume rm $(docker volume list -f dangling=true -q)

Remove ALL containers, images and volumes, to start from scratch:

docker rm -f $(docker ps -a -q)
docker rmi $(docker images -q)
docker volume rm $(docker volume ls -q)

Docker Cloud commands

The following commands can be run on a terminal in GLAMkit’s Django docker cloud container. First run bash to set up the environment.

Debug server

Run Django’s debug server on a cloud container, for debugging:

$ stop all

Then when you’ve finished and Ctrl-C exited runserver:

$ start all

Data dumps

Dump a database, encrypt it, and upload to the service, then delete the local copy:

$ pg_dump -O -x -f ~/dump.sql && cat ~/dump.sql|gpg -ac -o-|curl -X PUT --upload-file "-" && rm ~/dump.sql

Then on the destination machine, to download and decrypt:

$ curl [ url] | gpg -o- > dump.sql

Erase the current database if necessary:

$ dropdb $MYPROJECT_develop && createdb $MYPROJECT_develop

Finally, load the data:

$ psql < dump.sql
$ rm dump.sql

Uninstalling a GLAMkit project from Docker

Delete all containers with a name matching {project_name}:

$ docker rm $(docker ps -a -f "name={project_name}" -q)

To delete the associated images, run:

$ docker images #list all images

and for each image you want to delete:

$ docker rmi {image id}

If you are running other GLAMkit projects, then you only need to delete the image that starts with [project_name] - the other images will be used by other projects. To remove all “dangling” images (untagged and not referenced by a container):

$ docker rmi $(docker images -f "dangling=true" -q)

Finally, remove the project folder.