Building Base images in docker is not recommended but for those who are a bit interested in diving deeper in docker, this is a must-know thing. Even though the docker hub provides a huge collection of images for a variety of uses there are some cases where we would want to create something complex from SCRATCH !!!!.
That's where the Scratch base image from Docker comes in handy. There are several ways to generate base images, such as using an already-existing Linux machine or a running container, but for now, let's utilize a Docker scratch image.
To use scratch we just need to add FROM Scratch in our Dockerfiles. Yes, that's it! above this, you can add anything to configure your base image, Build it and it's ready to use.
For Example, let's create one. Create and Add the following to the Dockerfile.
FROM scratch
ADD hellofromdocker /
CMD ["/hellofromdocker"]
That's it here hellofromdocker is a static executable that does not have any runtime or linked dependencies. Since the scratch image only contains the bare minimum of runtime and settings needed to create base images, using other executables or apps may not work.
Once the Dockerfile is done. build an image using docker.
docker build -t helloscratchimg .
Spin up a container from a newly created base image and get hello from Docker! 🤩
Top comments (2)
Does the
hellofromdockerexecutable need to be compiled for the platform that docker is running? Ifhellofromdockeris created fromhellofromdocker.c, and I compile it on my Windows AMD64 platfrom, will thehelloscratchingimage run on, for example, Ubuntu on ARM?Yes, the executable needs to be compiled for the platform. You can find more information on this repository