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Can someone well versed in Docker explain in their own words what this does and why it is useful? Thanks in advance! I'm definitely not a docker poweruser...oth

• IMTDb 8y ago
  A docker image is built in layers that stack on top of each other. Think of each layer as a commit in a git repository. This project takes an image and shows the list of layers (=commits) and for each layer (=commit) allow you to see what was changed (=the diff). A bit like a git log for a docker image.
  • djsumdog 8y ago
    If OP looks up some Dockerfiles on docker hub, this will make more sense. Look at this mysql file for instance: https://github.com/docker-library/mysql/blob/696fc899126ae00771b5d87bdadae836e704ae7d/8.0/Dockerfile https://github.com/docker-library/mysql/blob/696fc899126ae00... If two Dockerfiles use debain:stretch-slim as their base, docker won't download both base images twice. Each command in the Dockerfile creates an image. If you copy a Dockerfile and just change the last line and build them in order, the 2nd build will run a lot faster and you'll see in the output it pulls out "cached images" since it's already run those commands (docker build --no-cache always forced a full build). If you start making Dockerfiles and playing around with it, it will start to make more sense.