@vivjo could you please give some context - is this happening in a course ? Or something that you are facing in you home lab or office lab ?
If this is a course lab - and you want a fresh lab env - just click on delete and recreate a fresh lab.
If you want troubleshooting then you need to either expand the filesystem ( lvm resize or extend ) or delete unwanted/old data from /.
use "du -hs /*" to see what is consuming the space and club it with sort and head/tail to get the top 10 or 20 example : du -kx / | sort -n | tail -20 and then especially check the /tmp & /var dir and use lsof to check if the previously deleted files are still open in /.
Check /boot for older kernels and delete older ones.
