After renaming /etc/hostname, Proxmox boots under the new node name and
looks for VM/CT configs in /etc/pve/nodes/<new>/qemu-server/. Without
migrating the directory first, all VMs appear missing after the reboot.
Now renames /etc/pve/nodes/<old>/ to /etc/pve/nodes/<new>/ while
pve-cluster is running (pmxcfs supports live rename). Also replaces
pvecm updatecerts -f with pvenode cert create --overwrite — pvecm
updatecerts restarts pve-cluster, unmounts /etc/pve and can crash VMs.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>