When running Docker on a system enforcing SELinux, Docker Volumes require a special SELinux context to be accessible by the Docker Daemon and Container.
This context is called container_file_t and can be set on a path recursively:
semanage fcontext -a -t container_file_t "<path>(/.*)?"
Afterwards, the context needs to be applied to already existing files:
restorecon -Rv <path>
Your <path> is now usable by Docker as a volume! 🥳