Nut upsuser - Feb 2018 - testing shutdown: pc not restarting; and "ups unavailable" messages

> It actually occurred to me that I could try this with another (any other)
computer here at work, so I did. I set the BIOS to "always on" after
power cut. I booted ubuntu. I did "sudo shutdown -h now" from the
console. The pc switched off as expected. Then I removed the power cable and
then plugged it back in. According to the theory above, this should have caused
the computer to detect a power loss and turn itself back on. Instead it remained
off (as I expected).
In light of the last few messages I tried again but this time I kept it off for
a few minutes rather than a few seconds before plugging the power cord back in,
and this time it did come back on. Wow! (That's still the computer at work,
though.)

If it is possible that this is motherboard-dependent I shall have to try again
with the media server computer at home that is supposed to be rescued by the
UPS. I envisage two cases.

1) if the computer does restart after I switch it off and then pull and (a while
later) reinsert the power cord, then it stands a chance of working with the UPS,
but I still need to understand why it hasn't worked so far.

2) if the computer stays off, there is little hope that any software
configuration of nut will make the ups turn it back on; except perhaps for
Lee's suggestion of "turning it off but not quite". On that note,
where in the file system should I be looking for the NUT shutdown script please?

> where in the filesystem should I be looking for the NUT shutdown script
please?

It's the SHUTDOWNCMD in upsmon.conf

nomad

On Thu, Feb 1, 2018 at 9:03 AM <nut.user.u830 at neverbox.com> wrote:
> > It actually occurred to me that I could try this with another (any
> other) computer here at work, so I did. I set the BIOS to "always
on" after
> power cut. I booted ubuntu. I did "sudo shutdown -h now" from the
console.
> The pc switched off as expected. Then I removed the power cable and then
> plugged it back in. According to the theory above, this should have caused
> the computer to detect a power loss and turn itself back on. Instead it
> remained off (as I expected).
>
> In light of the last few messages I tried again but this time I kept it
> off for a few minutes rather than a few seconds before plugging the power
> cord back in, and this time it did come back on. Wow! (That's still the
> computer at work, though.)
>
> If it is possible that this is motherboard-dependent I shall have to try
> again with the media server computer at home that is supposed to be rescued
> by the UPS. I envisage two cases.
>
> 1) if the computer does restart after I switch it off and then pull and (a
> while later) reinsert the power cord, then it stands a chance of working
> with the UPS, but I still need to understand why it hasn't worked so
far.
>
> 2) if the computer stays off, there is little hope that any software
> configuration of nut will make the ups turn it back on; except perhaps for
> Lee's suggestion of "turning it off but not quite". On that
note, where in
> the file system should I be looking for the NUT shutdown script please?
>
>
>
>
> _______________________________________________
> Nut-upsuser mailing list
> Nut-upsuser at lists.alioth.debian.org
> http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/nut-upsuser
>
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> > where in the filesystem should I be looking for the NUT shutdown
script please?
> 
> It's the SHUTDOWNCMD in upsmon.conf
Thanks!

> 
>>> where in the filesystem should I be looking for the NUT shutdown
script please?
>> 
>> It's the SHUTDOWNCMD in upsmon.conf
Excellent. And in my case (default) it says

SHUTDOWNCMD "/sbin/shutdown -h +0"

I have tried that command and, as expected, it has shut down the pc. Then I have
disconnected the power cord for one minute and plugged it back in, and the
computer has restarted by itself (thanks to the BIOS setting). I didn't
expect it, before this afternoon's explanations, but very good. It means it
should be possible for the UPS to wake up the computer by power-cycling it at
the socket, possibly with a sufficiently long delay between power down and power
up.

Now, why did the "testing shutdown" procedure not work? I can imagine
at least two reasons:

1) nut has properly shut down the computer, but the UPS has not removed power to
it. It was suggested I should test with a lamp whether the UPS is interrupting
power to the load during the shutdown procedure. This will have to wait until I
have a moment to wire a lamp with that so-called "type E plug
connector" so that it can plug into the "type F" that the UPS
uses for its 3 loads.
https://en.wikipedia.org/wiki/IEC_60320
<https://en.wikipedia.org/wiki/IEC_60320>

2) the UPS has power-cycled the load without enough of a delay between off and
on, and thus the computer has not had time to notice that there was a power cut.
(Some capacitor in the PSU hasn't fully discharged, or something.) This is
what happened this afternoon at work when I unplugged the switched-off pc and
plugged it back in again, and it didn't come on, whereas it did when I left
it off for a few minutes.

After I establish whether it's 1 or 2, would the fix be to add some
appropriate upscmd to the SHUTDOWNCMD entry in /etc/nut/upsmon.conf ?



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