If I understand well, you are trying to create a portable, standalone customized nexus3 installation in a self-contained docker image for testing/distribution purpose.
Doing this by extending the official nexus3 docker image will not work. Have a look at their Dockerfile: it defines a volume for /nexus_data
and there is currently no way of removing this from a child image.
It means that when your start a container without any specific options, a volume is created for each new container. This is why your committed image starts with blank data. The best you can do is to name the data volume when you start the container (option -v nexus_data:/nexus_data
for docker run
) so that the same volume is being reused. But the data will still be in your local docker installation, not in the image.
To do what you wish, you need to recreate you own docker image without a data volume. You can do it from the above official Dockerfile, just remove the volume line. Then you can customize and commit your container to an image which will contain the data.