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Dockstar - make it run commands when UPS says power low?

Posted by nigelhealy 
Dockstar - make it run commands when UPS says power low?
April 25, 2012 10:56PM
Hi, welcome from dirty-power California. My UPS protects my network-based equipment from brownouts average 3 times a day and whilst blackouts are rare, typically annually, I had an outage recently which ran long enough to flatten my UPS and the Debian Dockstar build on external USB stick was corrupted and I had to manually intervene, insert in a Linux laptop and do a fsck -t ext2 to repair the filesystem before the Dockstar would boot. Not good.

As a hack just now I did a tune2fs -c 0 to make it boot even if not cleanly shutdown, I can periodically do a fsck -t ext2 -y anyway manually periodically, but I'd prefer a graceful shutdown.

I plugged in the UPS vis USB and the dockstar recognized it, I don't have the dmesg messages to hand but it looked like it knew it was a UPS.

So my goal is to do 3 things:
- send outgoing mail, such as SMTP to gmail, to notify me remotely there is a power event
- send commands, such as SSH, to other systems to get them to gracefully shutdown. I'm thinking specifically the other Dockstar I have which would not be connected to the UPS via USB.
- finally shut itself down gracefully.

I know how to script, I know how to put commands in SSH and do the keygen thing so no passwords required. What I don't know how is to get the scripts triggered by specific status of the UPS. Its a APC make which is the most popular domestic UPS make.

I've done some searching and my needs are fairly simple, there is the Network UPS tools which seem a sledgehammer to crack a nut, is there something I can apt-get install in Debian which has simple battery-threshold commands?

Aside - one of my bootable USB sticks will ONLY cold boot, and another USB stick will ONLY warm boot. Cold boot is compatible with a power incident as it will be a cold boot when power is restored. Warm boot only is bad. I'll probably have to buy another 2GB USB and hope it cold boots.

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