[Nut-upsuser] Synology NAS is shutting down Ubuntu servers after very brief power outage

Todd Benivegna todd at benivegna.com
Sat Aug 1 21:25:09 BST 2020

I'm hoping that someone can shed some light on this… I have a Synology NAS (DS416) that has a feature where you can enable a “Network UPS Server” which is a NUT server.  I have been trying to get the Synology to shut down three Ubuntu 20.04 servers that I have. While it does work when I test it out manually, sometimes when I am away and the power goes out briefly, the servers shut down when the power has been out for like five seconds (or less sometimes).  When I come home and turn on the servers, they boot up but then immediately shut down again.  This happens until I restart the Synology; then they will boot up and stay up.  I‘d like them to stay up a little longer than that.  Ideally, I’d like them to stay up until battery is low, then shut down, then all come back on when power is restored.

This is what I have done so far:  I have enabled "Enable Network UPS server" on the Synology and have installed NUT on each of my servers running Ubuntu 20.04.  I have added the appropriate IPs to the Permitted DiskStation Devices” list.  I have also tried setting it on the Synology to shut down when battery is low and after a specified amount of time (20 minutes).  Either way, the servers will shut down after like 5 seconds or less.  I have edited upsmon.conf and added my MONITOR line and setup systemctl so that the nut-client service starts automatically at boot.  I have no made any other changes to the file; the rest is still set to defaults.

So I'm not sure where exactly the problem is; if it's the Synology or NUT on Ubuntu.  Strange thing is, when I manually test by shutting off the power briefly (or for a few seconds, or a few minutes - I've tried everything;) every time I do a test, everything works perfect and they will shut down when they are supposed to.  Seems to only happen when there is a passing storm that knocks the power out for a few seconds.

Also, this is what I found in the syslog on one of the machines:
Jul 31 18:33:29 plex upsmon[970]: UPS ups at on battery
Jul 31 18:33:34 plex upsmon[970]: UPS ups at on line power
Jul 31 18:34:04 plex upsmon[970]: Executing automatic power-fail shutdown
Jul 31 18:34:04 plex upsmon[970]: Auto logout and shutdown proceeding
Jul 31 18:34:09 plex systemd[1]: nut-monitor.service: Succeeded.

If I’m not mistaken, it is shutting down after power came back on line….?

Any help would be greatly appreciated!

Details:  Nut version 2.7.4-11ubuntu4, Ubuntu 20.04, NUT installed from package, Synology DS416, UPS is APC Back-UPS NS 650M1

Todd Benivegna // todd at benivegna.com
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