To install my microservice binaries I need a centos. And since I have 20 microservice I'm trying to find a way to optimize the images size so I'm wondering if there's a way to create a docker image without os and at the moment of deployment Docker takes the OS Layer from cache to put it in all the images.. I'm a beginner so I don't know if I'm clear in my statements ?
Yes, look at the scratch keyword (docs):
You can use Docker’s reserved, minimal image, scratch, as a starting point for building containers.
Also you may find useful using multi-stage builds.
An example:
FROM scratch
ADD hello /
FROM fedora
RUN yum -y update && yum clean all
RUN yum -y install nginx