The default kf2 maps don't have to be in the map cycle which we will edit later (won't show up in the server) but they are nice to have as a fall back / testing for <400MB depending on which maps you chose to save. I highly recommend keeping at least BioticLab (I personally keep two others) as thats the default starting map for the server if your container restarts right now. To do this, head to on your server /root/kf2/KFGame/BrewedPC/Maps/ and remove the maps you don't wish to use.

Free space on server by removing default mapsYou can gain back about 6GB if your only going to be using custom maps on your server.