CODEWITHSUNDEEP
docker
user7311580
user7311580

Reputation:

Docker - only image with operating system?

So far I have only seen images with some operating system as a base layer. Is this necessary ? Is it possible to run some container without an operating system ?

Upvotes: 1

Views: 83

Answers (2)

BMitch
BMitch

Reputation: 263627

There is FROM scratch which you'll find if you follow how the images on docker hub have been built (you may have to follow various FROM x lines to different images until you reach scratch). Scratch is empty, completely empty, no libraries, no shells, no files at all. It's designed as a starting point that you can copy a bunch of files into.

You can also use scratch if you have a statically linked binary and don't want anything else inside the container. However note that debugging the container becomes more difficult since you can't launch a shell inside the container, but that also means attackers can't do that either.

Upvotes: 0

Ricardo Branco
Ricardo Branco

Reputation: 6079

An operating system consist of the kernel and userland utilities. So, there are no Docker images with "operating systems" as base layer, but a lot of images named after operating system distributions with their particular userland utilities.

You can create a Docker image from a tarball with anything you like. But it wouldn't be useful if it lacks /bin/sh and you want to include a RUN in the Dockerfile.

Upvotes: 1

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