[Nut-upsuser] NUT auto-discovery [Was: Re: Nut problems with Centos and Belkin UPS]

Arjen de Korte nut+users at de-korte.org
Tue Nov 27 15:59:49 UTC 2007

> A big issue with auto-discovery is trust. You wouldn't want someone to
> be able to randomly shut down machines on your network just by
> starting a rogue copy of NUT.

Another problem is when you discover multiple UPS'es, which one you're
connected to? In a desktop system with only one UPS attached, this is a
moot issue, but I've seen as much a 15 UPS'es centrally monitored by one
server, all powering different parts of a server room. From which are we
receiving power?

> Then again, maybe it wouldn't be so bad if we combined auto-discovery
> with the SSL support in NUT. If I remember correctly, this means that
> the client only needs to have a list of accepted certificate
> authorities (which would most likely be generated in-house anyway),
> but it would be the same configuration for all client machines on the
> network.
> I can see this working well with the avahi multicast DNS daemon.

When you have only one UPS in your network, this might work. Otherwise,
one UPS going offline might cause all clients to shutdown. This is
probably not very desireable.

Note that we used to have (UDP) broadcast in earlier versions. We could
use that to announce UPS's and spare system administrators the trouble of
setting up a multicast DNS daemon in their network. But for the above
mentioned reason, I doubt this is going to add a lot of value without some
kind of configuration 'wizard' that would listen to these broadcasts and
allow selection of one UPS. I believe that something like that is part of
the new configuration stuff that Jonathan Dion worked on.

Best regards, Arjen
Eindhoven - The Netherlands
Key fingerprint - 66 4E 03 2C 9D B5 CB 9B  7A FE 7E C1 EE 88 BC 57

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