I can't take credit for this, but I definitely used this. Saving this for my future self looking for this again.
To clone docker volumes, you can transfer your files from one volume to another one. For that you have to manually create a new volume and then spin up a container to copy the contents.
Someone has already made a script for that, which you might use: https://github.com/gdiepen/docker-convenience-scripts/blob/master/docker_clone_volume.sh
If not, use the following commands (taken from the script):
# Supplement "old_volume" and "new_volume" for your real volume names docker volume create --name new_volume docker container run --rm -it \ -v old_volume:/from \ -v new_volume:/to \ alpine ash -c "cd /from ; cp -av . /to"