Right now I’m working with my work mates @opennms integrating the docker image building in our CI/CD environment. We build our container image based on CentOS and we noticed the caching doesn’t work for ${reasons}.
Running a docker build -t myimage . ended up always in installing packages from the official yum repositories even we haven’t changed anything in the Dockerfile.
To understand things better, I went back to drawing board and started with a simple example and rebuilding things step by step to understand when gets the docker build cache unnecessarily invalidated.
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