[Nut-upsuser] Redundant UPSes and dummy one

[Manuel Wolfshant]

On 6/17/22 11:55, PeReZ via Nut-upsuser wrote:
> I need to manage two UPSes but my host can set and monitor only one.

why only one ?


>
> So I thinked to install NUT UPS on a Raspberry to monitor both UPSes 
> and to create a dummy ups.
>
> The two UPSes are identical and both have LAN cards but I can connect 
> them via USB if desiderable.

All the UPSes I know that have LAN cards support SNMP so -- assuming 
yours do not deviate from this - you should be able to monitor both of 
them directly from any computer that can speak SNMP. You do not need the 
PI or the dummy UPS.


>
> Can I connect the Raspberry to the host via USB for dummy UPS 
> communications?
>
> The dummy ups should do:
> - notify ON_BATTERY if both UPSes are on battery
> - if both go on LOW battery, change its status to LOW battery also
> - send a shutdown comamnd to both UPSes with a delay of 5 minutes so 
> the host can gracefully stops all VMs and itself
> - turn off the Raspberry?
>
> The NUT server should send notifications on real status of both UPSes 
> via mail.
>
> Is it possible?

I guess it is but I fail to understand why do you complicate your life 
with this approach instead of monitoring both UPS via SNMP and maybe 
using setting two semaphores ( one per UPS ) and doing a logical AND 
between the conditions with a simple script written in any language of 
your choice.


wolfy