pve-manager 8.4.11 -> 8.4.20, corosync 3.1.9 -> 3.1.10-pve2, and kernel
6.8.12-42 staged on the /boot LV. dpkg clean, nothing outstanding for
apt -f install, all PVE services active, cluster quorate, no unapplied
conffiles. Reboot deliberately deferred at operator request, so the host
still runs 6.8.12-13 until a chosen window.
This validates the GRUB fix from 061c4b7 under the exact condition it
was written for. update-grub regenerated entries for the new kernel and
entry 0 -- what GRUB_DEFAULT=0 selects -- is now
/vmlinuz-6.8.12-42-pve with root=ZFS=nvme/ROOT/pve-1, supplied by the
grub.d drop-in since grub-mkconfig cannot derive the pool name itself.
The old kernel keeps correct entries as a fallback and the ext4 rollback
entry is untouched. Had the fix not landed first, saved_entry would
still be pinned to 6.8.12-13 and the host would boot the old kernel
indefinitely -- 161 security updates installed and never run.
/boot holds both kernel sets at 176M used of 488M, confirming the 512M
LV carved out of swap was sized correctly.
Adds a ZFS snapshot step to the upgrade playbook, taken automatically on
ZFS-root nodes before any package lands. That is the first real use of
the boot-environment upside the migration was meant to unlock: rollback
for this upgrade is now `zfs rollback -r
nvme/ROOT/pve-1@pre-upgrade-20260818T141652Z && reboot` rather than
archaeology in dpkg. Also documents that the corosync bump restarts
corosync mid-upgrade, which on a 2-node cluster is a brief quorum event.
vh
668b63a398