[Nut-upsuser] Redundant UPSes and dummy one

[Jim Klimov]

Adding to what others said, your best bet should be that the VM host
monitors two UPSes with two NUT driver instances (snmp or usb), and upsmon
client would specify that each UPS powers e.g. one of your two PSUs - and
one well-fed PSU is sufficient to run. Then when power does go critical,
upsmon would gracefully shut down the system where it runs calling a
SHUTDOWNCMD you can define (so handling VM hibernation/shutdown if that is
not handled as part of OS routine).

On Fri, Jun 17, 2022, 13:53 Manuel Wolfshant <wolfy at nobugconsulting.ro>
wrote:

> 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
>
>
>
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