[Nut-upsuser] abusing nut ups to do temperature shutdown WHILEmonitoring UPS'es

[Arjen de Korte]

> My thought was not to worry about shutting down the UPS. Since I want to
> manually start the servers after a temp shutdown then if the server powers
> off as a slave monitoring the fake UPS the server will never reboot as the
> UPS will stay powered on. Or I could just be totally out in left field.

That will only work if the system running the upsmon master for the 'real'
UPS, isn't monitoring the 'fake' UPS (if it is, it will set the
POWERDOWNFLAG and the UPS will reboot). Consequently, it will never know
that the temperature is too high. However, it is quite possible that by
shedding the load of 30 systems, the dissipation will drop enough so that
the room temperature stops rising, despite the lack of A/C. But that means
that you leave at least one system running (the upsmon master).

If that's OK, your solution is indeed simple enough. One resistor, some
wiring and a (mechanical) thermostat that opens a contact above a certain
temperature connected to a serial port should create something that
mimicks a contact closure UPS.

If not, you could still use a 'fake' UPS that is monitored by your upsmon
master and use the NOTIFYCMD to create a flag that prevents 'upsdrvctl
shutdown' from being called.

Best regards, Arjen
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