Ask how to use the information in the local file when creating a mirror using dockerfile.

  docker, question

I want to use Ubuntu16.04 to create a new image. I want to update the underlying Ubuntu before creating it, but it may be slower to use foreign image sources. Since my host uses Ubuntu16.04, can I copy the source.list in the host to the source.list in the mirror and update it? How to operate? Thank you


Dockerfile has COPY command