During the ubuntu.com outage, cloud-init's apt_configure module (once per
instance, at boot) spent two 10-second DNS timeouts looking for a mirror
and then wrote ubuntu.sources from its template, after the job had
started. On those VMs configure-apt-mirrors had already pointed the
sources at its list: apt-get update fetched every index for that list,
cloud-init put the image's mirror list back, and apt-get install found
no indexes for it, so no Ubuntu package had a candidate (materialcraft's
Flatpak x86_64 job, the FreeBSD tests job on 26.04). A repro on 12
runners failed on 8, every round, and a file watcher caught cloud-init's
write landing mid-update.
wait-for-cloud-init.sh runs `cloud-init status --wait` (at most 300 s,
never failing the job) before configure-apt-mirrors and
install-riscv64-cross's select-mirrors.sh touch anything.
FredApps
5d42870ead