Gitlab CI Cache with VirtualBox Runner

问题:

Gitlab CI VirtualBox runners do not support the Gitlab CI cache (as layed out in the documentation). However, I require a cache (primarily to cache my maven and node folders).

Are there known home-made workarounds/scripts, best practices or third party libraries for caching in VirtualBox runners?

Or in short: How can I cache specific folders when using Gitlab CI VirtualBox runners?