tsluyter
commented
4 years ago As per the comments in my pull request about shrinking: I've rethought our Docker strategy.
By defining "skf-labs/alpine37" we can make a common underlayer that applies to almost every container we make. This means that students will only need to "pull" that layer once, in order to build 1-N containers.
This approach means that the final container space grows a little, but in reality the storage space used will be even less than before! The big underlayers will be common/shared by all containers.
You may have noticed pull request 115 -> https://github.com/blabla1337/skf-labs/pull/115
I've been going over a few of your Docker files to make sure that the containers we produce are as small as possible. For students with limited resources (young students, developing countries, little expendable income) storage space can come at a premium. Shrinking our requirements by 60% seems like a very user-friendly thing to do.
With my proposed refactoring, our resulting containers go down from an average 330MB to ~77MB.
The biggest factor in the current ~330MB size per container, lies in the fact that the whole SKF Labs Git repo is pulled into the container and then never removed. By refactoring the Dockerfile to git pull, and then only copying the needed content, it's a huge space-saver already.
Another nice way to save space on our layers is to combine into one RUN the apk add, the pip intall and the apk del to immediately remove unneeded packages.
In the past, some of our students complained that editing the source files with all the ^M (Windows) line endings in place is troublesome. These occur, depending on whom built the container where. To resolve this issue I've started including dos2unix into each Dockerfile, to clean up any scripts and other text-based files. I'm considering adding nano into the containers for those completely unfamiliar with vi.
Please let me know if you'd like me to continue these activities.