howto/upgrades.md

@@ -322,6 +322,16 @@ See the [Ganeti reboot procedures](howto/ganeti#rebooting) for this procedure.
 The [Nagios unhandled problems](https://nagios.torproject.org/cgi-bin/icinga/status.cgi?allunhandledproblems) will show remaining hosts that
 might have been missed by the above procedure. 
 
+But if you want to run more upgrades in parallels and are doing a
+fleet-wide reboot, while running the Ganeti reboots (above), you can
+perform reboots on the hosts *not* on Ganeti cluster by pulling the
+list of hosts from LDAP:
+
+    ldapsearch -H ldap://db.torproject.org -x -ZZ -b "ou=hosts,dc=torproject,dc=org" '(!(physicalHost=gnt-*))' hostname | sed -n '/hostname/{s/hostname: //;p}' | sort
+
+... and then pick the hosts judiciously to avoid overlapping with
+hosts in the same rotation currently rebooting in Ganeti.
+
 ## Userland reboots
 
 systemd 254 (Debian 13 trixie and above) has a special command: