dockerfile中的信息在哪里？

Question

There is a container, that a lot of work was done on (partly within dockerfile, partly within container itself-blatant approach from within) and it got detached from dockerfile. Anyone knows where docker stores information, collected from ENTYPOINT? It's probably some file docker creates, that is been started upon docker start [container] and docker run -it [container sum] . Need to edit that and really don't want to start from the beginning. Pretty sure don't need to, cause one can work on containers without having original dockerfile.

General documentation on docker site doesn't give any insight into that

I was advised to directly edit /var/lib/docker/container/[container #]/config.v2.json Tried that and the result is the following: If I edit Entrypoint (I'll try to provide image how it looks) - s7.photobucket.com/user/309339939/media/docker.jpg.html

It doesn't help, since the value isn't saved to new after docker commit . However, if I change cmd , then it is saved. Conclusion: Entrypoint depends on something else besides that file. Any ideas?

Answer 1

Docker does not save it's data in the form of a Dockerfile, this file is an input that is "compiled" into the layers and configuration of an image. There are several things you can do to get an idea of the changes, but rebuilding another Dockerfile will be a process that needs to be done by hand:

• docker history will give you a list of all the layers and their commands, though many of these commands may not be easily reproducible if outside data was used or you committed a container.

• docker diff will show the changes to the filesystem by a container. This is essentially what goes into each layer of a docker image when you build it.

• docker inspect will give you all the environment settings and other configurations of an image or container.

• docker save will export an image into a tar format that can be later loaded back into another docker engine.