Final Update From the OP
All sites restored and server rebooting fine. The image from Ionos was definitely the problem.
Glad you got it sorted.
And glad VM was not at fault.
Ubuntu 24 LTS EOL is 2034 btw.
Any reason you need 26 in particular?
David
There’s no harm in using the latest supported OS version, as long as you’re aware it is new and less tested. I don’t think it’s necessarily a problem with 26.04. It seems to be something specific to the custom Ionos image, based on Geoff’s follow-up.
I have the same problem, not on ionos - fresh 26.04.01 on binarylane (checked re-booted OK first), then fresh virtualmin install (lemp, mini, no mariadb, postgres) - then log in OK to virtualmin, do wizard to say start postgres and not mariadb, do the recheck configuration thing, and then see Warning reboot required, so I do that, but boot stalls with similar screen as OP:
I manually applied this suggested fix onto a fresh 26.04.01 install, then installed fresh virtualmin, and now it reboots OK: fix(net): avoid boot deadlock when starting systemd-networkd-wait-online by AryanHamedani · Pull Request #7053 · canonical/cloud-init · GitHub
I am only as expert on this as Claude lets me be. Looks like perhaps a timing/race condition in 26.04.01 cloud-init that was exposed when virtualmin had added more boot-time workload. But is cloud-init meant to only run once per machine install and not thereafter? I had booted and rebooted before installing virtualmin, so why did cloud-init run again? Does virtualmin invoke it, or does installing virtualmin cause cloud-init to be re-run on next boot?
cloud-init runs the network part every boot, unless carefully disabled.
See my earlier post this thread, and the post by jimr1 just under mine.
No. cloud-init is a configuration management layer that always runs, if it is being used. Many hosting providers use it for network configuration and possibly other things. It is a good idea, can be very useful, but it’s proven to be pretty fragile, so far. We’ve seen a lot of users have boot problems due to issues related to cloud-init (Debian/Ubuntu packaging problem in one case, often due to misconfiguration by hosting providers in other cases, and sometimes due to bugs in cloud-init itself).