What is docker s scratch image

Question

I'm new to Docker and was experimenting with the first hello world example in the documentation. The hello-world image, as far as I can tell, is built on top of the scratch image. Is it possible for someone to explain how the scratch image works? It's essentially blank, as far as I can tell. So, how is the binary in the hello-world image executed?

Answer 1

The scratch image is Docker's most basic image. All other photos have this as their ancestor. The scratch image is, in fact, blank. There are no folders or files in it...

Scratch pictures are mostly used to create other basic images. For example, the debian image is created from the ground up like follows:

FROM scratch
ADD rootfs.tar.xz /
CMD ["bash"]

All of the system files are contained in rootfs.tar.xz. The filesystem directories are added to the scratch image, which is currently empty, by the Debian image.

The scratch image is completely empty. The hello-world executable included in the scratch image is statically compiled, which means it is self-contained and doesn't require any external libraries to run.