User's Manual UPS control system

Please note, there are reports that you must use UPSTYPE smartups on
the slave even if the master is using UPSTYPE dumb. This is apparently
some bug in the new dumb driver.
In this configuration, the shutdown will be initiated by the master. It is also
possible to specify BATTERYLEVEL, MINUTES, and TIMEOUT configu-
ration directives in the Slave machine that will cause the slave to shutdown
before the master. This can often be useful if the slave is less important
than the master and you wish to reduce battery power consumption so that
the master can remain up longer during a power outage.
Variation on the Master/Slave Configuration
It is also possible to have a Master/Slave configuration where the Slave is
powered by a different UPS (or any other power source), but is nevertheless
controlled (i.e. shutdown) by the master. The setup would be identical
to the Master/Slave configuration files shown above. The only difference is
where the slave actually receives its power. In effect, apcupsd does not know
or care where the power really comes from.
A Sample NIS Slave Configuration Using the Net Driver
As opposed to the old master/slave mode demonstrated above, you can
turn any computer into an NIS slave by configuring with the NIS network
driver turned on --enable-net. The difference is that the NIS server has
no explicit knowledge of the slaves. The NIS server makes its information
available via the net (NIS), and the NIS slaves read it. When the NIS server
is going to shutdown, it makes the information available to any NIS slave
that polls it, but the NIS server does not explicitly call each NIS slave as is
the case in the Master/Slave networking described several sections above.
Running in this configuration, you can use any computer with apcupsd
running the Network Information Server (NIS) as the server. The NIS slave
simply uses the NIS information to decide when to shutdown. This is a
much simpler mode than the older master/slave code mentioned above.
The main apcupsd (NIS server) is connected to the UPS and has NIS turned
on, but the configuration is a simple standalone as in the section A Sim-
ple Configuration for a SmartUPS. It doesn’t matter how the UPS is
connected to the computer (serial, USB, ...).
For the NIS slave computer, you will have a configuration that looks some-
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