Both instances at https://tools.wmflabs.org/openstack-browser/project/discourse need more free space in order to upgrade Discourse. https://discourse.wmflabs.org/ has ~3GB free and cannot be upgraded regularly anymore. https://discourse-mediawiki.wmflabs.org/ has ~5GB free and could still be upgraded, running the option to clean Docker containers.
There is something fishy here. Discourse and our content & backups don't require the space that is being taken, not at all. After a quick inspection, both instances seem to have growing Docker directories under /var/lib. discourse1002.discourse.eqiad.wmflabs also has multiple GBs in directories for devicemapper and overlay that I believe we are not using anymore.
Searching around I have found pages about Docker folders growing endlessly and what to do with them, but I don't dare to touch anything because my Docker knowledge is very limited, and that is already an overstatement. I don't even know whether the old devicemapper and overlay directories can be simply rm or they should be purged with some Docker instruction.
Please help. :)