Docker Hub is not the only source for images
Private registries can be based on Distribution
docker run --name registry --detach \
--publish localhost:5000:5000 \
registry
docker tag docker-compose:1.29.2 localhost:5000/docker-compose:1.29.2
docker push localhost:5000/docker-compose:1.29.2
localhost:5000
is preconfigured as insecure registry
Other registries must be secure (HTTPS)