VirtualBox Linked Clones
A significant hazard appears.
Just a quick note here.
If you are using VirtualBox’s Linked Clones feature, where the clones you make are just an on disk diff of the original machine, much like a ZFS snapshot …
And they’re running an older version of Ubuntu, say you made some containers with Ubuntu Budgie 23.10, when the time comes for do-release-upgrade …
The primary VM will work as expected, but the Linked Clones will compel you to do a dozen incremental apt update; apt dist-upgrade …
And the terminal condition will be a dozen packages in “kept back”, which can’t be upgraded, and do-release-upgrade will not proceed.
Having lots of hands on time with Ubuntu, the bulk of this was my old nemesis - the cups printing packages. For those rare occasions when I do want to print something, I sneakernet a PDF to someone else’s computer that’s got a printer plugged into it, and do the deed there. Removing cups is only slightly less complex than removing your own appendix. I started the process, met the usual hazards, and then an apt upgrade brought everything forward.
So do-release-upgrade is running now, but this is NOT a deterministic process.
This is a bit deeper than Secure Shell & Rsync Tips, but had my million monkeys/million keyboards approach not worked, I would have used rsync to extract the /home directory tree to my workstation. Once that was done I’d use a fresh Budgie 24.04 install and send /home to it, then wade through the grief of installing the packages I use. Doing it in that order is tolerable for me, but there’s a lot of nuance in this area - you CAN move a Signal install from one shell account to another, but I know this only because I got fed up with a flaky phone and gave it a try, expecting to write off the whole account.
This probably should have been a Stack Exchange question, but I just wanted to get it out of my head so I can get on to whatever comes next, on this sunny, windy Wednesday.