Docker for Rails Developers

Quick Recap

Our Dockerfile scrubs up pretty well. You can put the wrench down, take off those oil-stained overalls, and put your feet up—again, metaphorically speaking. You deserve it.

Let’s review what we covered:

1. We saw how to name and version our images by giving them tags, either after they’re built:

   $ docker tag a1df0eddba18 railsapp

   or at build time (here setting two tags):

   $ docker build -t railsapp -t railsapp:1.0 .

2. We added a default command to our image using the CMD instruction:

   CMD ["bin/rails", "s", "-b", "0.0.0.0"]

3. We sped up our image builds by using a .dockerignore to prevent unnecessary files from being sent to the Docker daemon as part of our build context.

4. We ensured that we ...