Base Docker Image for Meteor Apps
You can build/bundle your Meteor app as part of building your Docker image, rather than outside of Docker before the Docker build. This means the machine doing the building need not have Node or Meteor installed, which is important for continuous integration setups; and ensures repeatable builds, since the build environment is isolated and controlled.
Using a multistage
Dockerfileon your app’s side means that you can publish a much smaller final Docker image that doesn’t have Meteor included, and you can also use an Alpine Linux base which is good for passing security scans (as it presents much less surface area in which scanners might find vulnerabilities).
example/Dockerfile into the root of your project. This file assumes that your Meteor app is one level down from the root in a folder named
app; either move your app there, or edit
Dockerfile to point to your desired path (or the root of your project). Leave
Dockerfile at the root.
Also copy in
example/docker-compose.yml to your project’s root. Then, from the root of your project:
This builds an image for your app and starts it, along with a linked container for MongoDB. Go to http://localhost/ to see your app running.
Feel free to edit the
Dockerfile you copied into your project, for example to add Linux dependencies. The beauty of the multistage build pattern is that this base image can stay lean, without needing
ONBUILD triggers or configuration files for you to influence the image that gets built. You control the final image via your own
Dockerfile, so you can do whatever you want.
Why this image, instead of some others?
There are several great Meteor Docker images out there. We built this one because none of the existing open source ones met our needs:
jshimko/meteor-launchpad is great, but it’s based on
debian:jessie, which fails the security scan we run on all of our Docker images. Debian is also larger than Alpine. This project also always downloads and installs Meteor on every production build, rather than caching it as this base image does.
meteor/galaxy-images and Treecom/meteor-alpine both require building the Meteor app in the host machine, before copying the built app into the Docker container. We wanted to avoid needing Node and Meteor installed on our CI servers, and we want the predictability of building within the Docker environment.
Other projects I looked at generally had one or more of the disadvantages cited above. Multistage Docker builds have only been possible since Docker 17.05, which came out in May 2017, and most projects on the Web were designed before then and therefore don’t take advantage of the possibilities offered by a multistage architecture.