[Nut-upsuser] Slave as master

Arjen de Korte nut+users at de-korte.org
Wed Jun 3 19:14:21 UTC 2009

Citeren Rob MacGregor <rob.macgregor op gmail.com>:

>> I have a similar question to this as well, in that I have my server set up
>> using NUT with a SOLA-330 (working nicely!) and my desktop is using an APC
>> BackUPS-300 (this model has no serial/USB comms) as the SOLA & APC are rated
>> the same, I was wanting my server to send a broadcast packet across my LAN
>> to force all PC's (that are still powered by UPS's) to shut down... (I have
>> a third desktop without a UPS at this time! and in the event of a power
>> outage this will already be down!)
>> Is this possible to be done? if so, where can I find such information?
> A machine can be a master for an UPS that it isn't powered by.  The
> documentation has covered this for at least 5 years now ;)

There seems to be a lot of confusion about the meaning of  
'master/slave' for 'upsmon'. The major difference between 'upsmon'  
running as master or as a slave, is that when it is a master for a  
certain UPS, it can command it to shutdown. Whether or not it is  
powered by said UPS is of no importance for that (although in most  
cases, both master and slaves will be). See also 'man 8 upsmon' for  
more information on this.

The second thing is, that there is no need for a 'upsmon' to be  
powered by a UPS in order to run. It is quite possible, to listen in  
on a UPS and shutdown a system if the UPS is shutting down. See the  
explanation of MONITOR and MINSUPPLIES in 'man 8 upsmon.conf'.

Best regards, Arjen
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