Nut upsuser - May 2015 - Are UPS shutdown commands automatically sent?

Roger,

So I'm pursuing the strategy of issuing the "upsdrvctl shutdown"
command script when the OS (Porteus, in this case) is shutting down.  I so far
can't get it to do it, but I'm sure I'll overcome it, but I realized
something else might be a problem.

Won't that script execute every time Linux is shutting down, including
rebooting?  So, if I choose to reboot  my system, I would most likely see the
UPS shutoff and then turn back on, somewhere in the middle of my system booting
back up.

I can think of a couple solutions:
1) Have the script verify that the UPS is actually in a OB state before giving
the shutdown command.  That should prevent unintended UPS power cycles when
simply rebooting the system.
2) Have the UPS itself not respect any "load.off.delay" or similar
commands when it is online.

Looking over UPS documentation and various helps, it seems most people would
expect their UPS to turn the load off and then back on, even if it has wall
power the entire time.  That would facilitate testing at a minimum.  So I'm
guessing option #2 isn't a good one.

Is #1 the correct way to deal with this?  Or am I misunderstanding the problem
(as in, there IS no problem)?  It seems like this would have been dealt with
before by people who interact with UPS and NUT more often than I.

Sincerely,
Robert G. Groner
Software Engineer

RTD Embedded Technologies, Inc.
ISO 9001 and AS9100 Certified
Ph: 814-234-8087
www.rtd.com
-----Original Message-----
From: Roger Price [mailto:roger at rogerprice.org]
Sent: Thursday, May 21, 2015 3:59 PM
To: Rob Groner
Subject: Re: [Nut-upsuser] Are UPS shutdown commands automatically sent?

On Thu, 21 May 2015, Rob Groner wrote:
> I?m testing that my system will shutdown when the UPS has been on 
> battery for 10 seconds.? That all works fine?.10 seconds after pulling 
> the plug, my system does shut down.? However, I am not getting the 
> commands into the UPS telling it to power off and then power on.? I had
thought I read somewhere that these commands are sent automatically when ?upsmon
?c fsd? happens?but I can?t find that, nor can I find any clear instructions on
where I would put the commands to tell the UPS to start its shutdown and restart
timers.
Hi, I went through the same learning curve.  I wrote up my notes at
http://rogerprice.org/NUT.html Perhaps there is something there that could help
you.  Best Regards, Roger

On Fri, 22 May 2015, Rob Groner wrote:
> So I'm pursuing the strategy of issuing the "upsdrvctl
shutdown" command
> script when the OS (Porteus, in this case) is shutting down.  I so far 
> can't get it to do it, but I'm sure I'll overcome it, but I
realized
> something else might be a problem.
>
> Won't that script execute every time Linux is shutting down, including 
> rebooting?  So, if I choose to reboot my system, I would most likely see 
> the UPS shutoff and then turn back on, somewhere in the middle of my 
> system booting back up.
Hello Robert, The command /sbin/shutdown -r used to reboot the box is 
incompatible with a UPS which receives a delayed shutdown order. If you 
have offdelay = 30 in /etc/ups/ups.conf, then 30 seconds after the 
upsdrvctl shutdown, when the box has now probably restarted, the UPS will 
shutdown with total loss of power to the box.  Not good.
> I can think of a couple solutions: 1) Have the script verify that the 
> UPS is actually in a OB state before giving the shutdown command.  That 
> should prevent unintended UPS power cycles when simply rebooting the 
> system. 2) Have the UPS itself not respect any "load.off.delay"
or
> similar commands when it is online.
This adds complexity, and in a critical system component simplicity is a 
virtue.  To reboot my box, I turn off the wall power and wait until I hear 
the "clunk" as the shutdown relay operates in the UPS.  I then turn
the
wall power back on.
> Looking over UPS documentation and various helps, it seems most people 
> would expect their UPS to turn the load off and then back on, even if it 
> has wall power the entire time.  That would facilitate testing at a 
> minimum.  So I'm guessing option #2 isn't a good one.
If you have decided to use a UPS capable of shutting down and restarting 
when wall power comes back, then you have to respect the UPS cycle.  You 
can't pretend it isn't there.

Best regards, Roger

Roger,

Following your guide, it now works great, shutting down the UPS after the system
has shutdown.  I went with the bash script method.

I have noticed, however, that the command to the UPS to do the delayed shutdown
comes RIGHT as openSUSE is shutting down.  While that is a good thing as far as
timing and the potential race is concerned, I have seen it once where the UPS
received the command to do the delayed shutdown, but *not* the command to do the
delayed restart.  While that's not a critical failure, it would be if the
UPS doesn't get the delayed shutdown command instead.

I'm wondering if the system (openSUSE ) died before that particular command
could be sent over USB to the UPS.

Sincerely,
Robert G. Groner
Software Engineer

RTD Embedded Technologies, Inc.
ISO 9001 and AS9100 Certified
Ph: 814-234-8087
www.rtd.com

-----Original Message-----
From: Nut-upsuser [mailto:nut-upsuser-bounces+rgroner=rtd.com at
lists.alioth.debian.org] On Behalf Of Roger Price
Sent: Saturday, May 23, 2015 6:02 AM
To: nut-upsuser Mailing List
Subject: Re: [Nut-upsuser] Are UPS shutdown commands automatically sent?

On Fri, 22 May 2015, Rob Groner wrote:
> So I'm pursuing the strategy of issuing the "upsdrvctl
shutdown"
> command script when the OS (Porteus, in this case) is shutting down.  
> I so far can't get it to do it, but I'm sure I'll overcome it,
but I
> realized something else might be a problem.
>
> Won't that script execute every time Linux is shutting down, including 
> rebooting?  So, if I choose to reboot my system, I would most likely 
> see the UPS shutoff and then turn back on, somewhere in the middle of 
> my system booting back up.
Hello Robert, The command /sbin/shutdown -r used to reboot the box is
incompatible with a UPS which receives a delayed shutdown order. If you have
offdelay = 30 in /etc/ups/ups.conf, then 30 seconds after the upsdrvctl
shutdown, when the box has now probably restarted, the UPS will shutdown with
total loss of power to the box.  Not good.
> I can think of a couple solutions: 1) Have the script verify that the 
> UPS is actually in a OB state before giving the shutdown command.  
> That should prevent unintended UPS power cycles when simply rebooting 
> the system. 2) Have the UPS itself not respect any
"load.off.delay" or
> similar commands when it is online.
This adds complexity, and in a critical system component simplicity is a virtue.
To reboot my box, I turn off the wall power and wait until I hear the
"clunk" as the shutdown relay operates in the UPS.  I then turn the
wall power back on.
> Looking over UPS documentation and various helps, it seems most people 
> would expect their UPS to turn the load off and then back on, even if 
> it has wall power the entire time.  That would facilitate testing at a 
> minimum.  So I'm guessing option #2 isn't a good one.
If you have decided to use a UPS capable of shutting down and restarting when
wall power comes back, then you have to respect the UPS cycle.  You can't
pretend it isn't there.

Best regards, Roger

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