[Nut-upsuser] confusion about shutdown

[Greg Troxel]

maybe me, maybe docs.

I have never had auto shutdown set up on netbsd.  Mostly I monitor to
mqtt.  But now I'm trying and have multiple confusions.

1) 'upsdrvctl shutdown' vs 'upscmd shutdown.return'

upsdrvctl is about stopping the driver, but lowbatt shutdown wants to
send a command.  I don't get the upsmon example file:

  # POWERDOWNFLAG - Flag file for forcing UPS shutdown on the primary system
  #
  # upsmon will create a file with this name in primary mode when it's time
  # to shut down the load.  You should check for this file's existence in
  # your shutdown scripts and run 'upsdrvctl shutdown' if it exists, to tell
  # the UPS(es) to power off.


2) LB config.   On a Best Fortress, I can set lowbatt runtime, but only
3 digits, even though I want 1800s.   Is this likely a Fortress
limitation, or a bug?  I will read the source...

2A) seems like nut should be able to have time-based config to start
shutdown, all of batt%, seconds remaining, and seconds on battery, built
in.

3) seems like shutdown should remove /etc/killpower but maybe upsmon
removes it at boot.  should be explained more, probably, guessing it is
at boot since fs is ro

4) not clear where I should edit in the instant command, as it doesn't
belong when shutting down upsd, but yet it has to be before.  This is
complicated.

Any working code on NetBSD?