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Project idea: a Google for docker images. Search for files by hash within all public docker images. Find images that contain a certain piece of code. Reverse engineering Dockerfiles for those that were built without.
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...other than build start and stopping..
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.
Project idea: a Google for docker images. Search for files by hash within all public docker images. Find images that contain a certain piece of code. Reverse engineering Dockerfiles for those that were built without.
Every layer understands the command it was run in the Dockerfile to create itself. Just look at `docker history` and have a look at the "CREATED BY" field for human-readable output of the layer metadata, or depending on your graph driver have a look in /var/lib/docker/image/overlay2/imagedb/content/sha256. From there you can reverse-engineer a Dockerfile.
For layers that were not built using `docker build` (e.g. `docker commit`, OCI-compatible image builders), re-creating the exact command that generated that layer is much harder to do. The only information most tools will give you might just be the diff itself.
Is there a tool to compare 2 or more images to check which layers they have in common?
This requires that you have logged in to the registry, pushed the image to the registry and have `docker pull` rights for the image. You could also run a registry locally, push your image there and inspect your registry's storage db. There's just no CLI command to do that.
Project idea: a Google for docker images. Search for files by hash within all public docker images. Find images that contain a certain piece of code. Reverse engineering Dockerfiles for those that were built without.
The latter can be easily done in a few hours by inspecting the image layer metadata. Every layer understands the command it was run in the Dockerfile to create itself. Just look at `docker history` and have a look at the "CREATED BY" field for human-readable output of the layer metadata, or depending on your graph driver have a look in /var/lib/docker/image/overlay2/imagedb/content/sha256. From there you can reverse-…
New project idea ... Crawl a large set of popular docker images lacking Dockerfiles and attempt to recreate the dockerfile with this technique.
Is there a tool to compare 2 or more images to check which layers they have in common?
There's no tool I'm aware of, but with experimental features enabled in the Docker CLI you can use `docker manifest inspect` on each image manifest and diff the content. e.g. `docker manifest inspect ubuntu:latest`. This requires that you have logged in to the registry, pushed the image to the registry and have `docker pull` rights for the image. You could also run a registry locally, push your image there and inspec…