[Nut-upsuser] Shutdown order for servers

[Roger Price]

On Thu, 17 Sep 2020, Kirill Nikonorov wrote:

> Hello to All!
> It might be not exactly NUT question but implementation.
> I have a rack with one UPS and several servers getting power from this device. One server is a master and other are slaves. All systems are running Debian
> 4.15.3 kernel and APC UPS. Everything works fine but what I need is to make an order for shutting down servers as they have different roles.
> Is it possible to configure SQL and VM servers to go down first, then mail server, then NAS and UPS master as the last one after all of them?
> I see that in case of power outage all servers receive signal from master simultaneously. May I change the order somehow?

Nut provides a directive HOSTSYNC [1] in upsmon.conf :

  HOSTSYNC seconds

  upsmon will wait up to this many seconds in master mode for the slaves to
  disconnect during a shutdown situation. By default, this is 15 seconds.

But this looks as if it is not a sufficiently staged approach for your needs. 
If you need something more sequenced, it will be necessary to use upssched to 
drive a script which does what you want.

Roger

[1] https://networkupstools.org/docs/man/upsmon.conf.html