Docker Cheat Sheet

docker-cheat-sheet.md

Docker Cheat Sheet

Testing with goss and dgoss

On the Mac

1. install goss

   curl -L https://github.com/aelsabbahy/goss/releases/download/v0.3.7/goss-linux-amd64 -o /usr/local/bin/goss
   curl -L https://raw.githubusercontent.com/aelsabbahy/goss/master/extras/dgoss/dgoss -o /usr/local/bin/dgoss
   chmod +rx /usr/local/bin/dgoss
   

2. add the following line to your ~/.profile or .zshrc

   export GOSS_PATH=/usr/local/bin/goss
   

3. within the directory that contains your Dockerfile (where you want to create a goss.yml with tests) run

   dgoss edit -p 8080:80 <IMAGE NAME>
   

4. add some checks with goss a ... and quit the editor with exit

   goss a port 80
   goss a http http://localhost
   exit
   

5. run the tests against the container with

   dgoss run <IMAGE NAME>
   

Docker in Docker on Mac

1. Create a Docker image that contains the docker binary

   FROM ...
   
   RUN apt-get update
   RUN apt-get -y install docker.io
   
   ENV GOSS_PATH="/usr/local/bin/goss"
   ENV GOSS_FILES_STRATEGY="cp"
   

2. Start a container and mount the docker socket and install docker binary

   mkdir /tmp/docker
   docker run -it -v /var/run/docker.sock:/var/run/docker.sock - /tmp/docker:/tmp <IMAGE NAME>
   

Resources

Docker Testing

• https://github.com/aelsabbahy/goss
  • https://github.com/aelsabbahy/goss/tree/master/extras/dgoss
• https://medium.com/@aelsabbahy/tutorial-how-to-test-your-docker-image-in-half-a-second-bbd13e06a4a9
• container testing à la Google https://opensource.googleblog.com/2018/01/container-structure-tests-unit-tests.html
  • Bazel https://www.bazel.build/
  • Bazel for Docker https://github.com/bazelbuild/rules_docker

Docker Administration

• https://www.digitalocean.com/community/tutorials/how-to-remove-docker-images-containers-and-volumes

• tini - A tiny but valid init for containers https://github.com/krallin/tini

• Play with Docker Classroom http://training.play-with-docker.com/