The upgrade from 14.04 LTS to 16.04 LTS a few years ago was unproblematic, as I recall. So I was hoping this latest upgrade would go smoothly. It did not.
TL;DR: 3 big problems came up, but were fixable, thanks to solutions and ideas published by earlier adopters.
First I did the upgrade on my Kubuntu computer, a full-tower desktop machine which is also getting long in the tooth. That upgrade was slow, but mostly due to the WiFi situation upstairs in the home office. The throughput is not great, but good enough for work. After the slowness of that upgrade, everything else seemed to run pretty smoothly — just a few config file questions for me answer and it did everything else by itself.
So I set about upgrading my 2007 Mac mini from Ubuntu 16.04 to 18.04, and was quite pleased with the download speeds (duh…it’s connected directly the cable modem via ethernet). After the downloads completed in a third of the time or less, a quick reboot and I’d be in business. Or so I thought. I encountered one problem after another. Fortunately, others found these problems before me and published them. I am paying it forward for you here.
Wayland
It would hang on the startup screen and never let me log in. I mostly run this box headless, but every now and again I like a GUI for it. So I googled.
https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/1767606
There’s some incompatibility between Wayland and the GNOME desktop manager and the integrated graphics card on my Mac mini’s motherboard. Solution: fall back to Xorg instead of Wayland. Edit the /etc/gdm3/custom.conf file and uncomment the line WaylandEnable=false.
DNS
After I got the display manager working, I quickly saw that no internet stuff dependent on domain names was working. Hard-coded addresses, like for the machines on my LAN, seemed to work fine. More googling led me to comment out the line:
dns=dnsmasq
… in the file /etc/NetworkManger/NetworkManager.conf so as to not use the systemd DNS-stub thing from systemd pointing to 127.0.0.53 or whatever. After a reboot, domain name resolution starting working again.
apt and $LANGUAGE in my locale
OK, DNS resolution was working again. I wanted to get the freshest versions of the packages (maybe fixing the previous problems). Reading the package lists with sudo apt update was running extremely slowly — several minutes just to advance from 1% to 2%, whereas this part of the task is over and done with normally quite quickly. I googled some more and found something to try here:
https://askubuntu.com/questions/251781/reading-package-list-takes-forever/327444 (kinda far down on the page)
Apparently the $LANGUAGE variable needs to be in the form of a two-character lower-case ISO code, like “en”. Mine had been set to something like “en_US.UTF-8” and it had never caused problems for me before. But I used localectl set-locale LANGUAGE=en to update it, and after a new login, things were working normally again.
Conclusion
I wonder when that old mid-2007 Mac mini will no longer be supported by the likes of Debian and Ubuntu. 11 years later though — it’s still chugging along with maxed-out RAM and an SSD HD upgrade along the way.