Nut upsuser - Mar 2024 - NUT in a Master / Slave Environment - How things work

Hi,

I would like to confirm my understanding of how NUT operates in a Master /
Server environment.  Some areas are not clear.

1 Power fails
2. Nut Master polls the UPS according to *POLLFREQ (in seconds)* setting in
*upsmon.conf*.
    2.1 When *battery.runtime.low (in seconds)* or *battery.charge.low (in
%)* are greater than the ups reported value a *Low Battery (LB)* condition
becomes true.
3. As soon as a *LB* happens
    3.1 A counter that will be checked against *ups.delay.shutdown*
    3.2 The *master *sends a signal to the *slaves *(how??)
    3.3 The slaves shut down themselves
          *Do they send a signal to master? *
*          What mechanisms are used to ensure that the slaves shut down
before the master starts its own shutdown* (this is critical for Virtual
environments in which guests need to power off before the host).
     3.4 At which point does *master* start shutting itself down?
     3.5 After *ups.delay.shutdown* has passed, the *ups *shutdowns itself.

Thanks and regards,
Alan
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