Configuring Eaton 3S UPS with Fedora 30

First off, make sure your UPS is connected. On my system, I had to use a different USB port as it was disconnecting regularly for some reason - probably USB power issues which is funny since this is a power device:

# dmesg
# lsusb

Install and configure nut software:

# dnf -y install nut

# grep ^MODE /etc/ups/nut.conf
MODE=standalone

# grep -v '^#' /etc/ups/ups.conf
[eaton3s]
driver=usbhid-ups
port=auto

# grep -v '^#' /etc/ups/upsmon.conf | egrep -v '^$'
MONITOR eaton3s@localhost 1 monuser pass master
MINSUPPLIES 1
SHUTDOWNCMD "/sbin/shutdown -h +0"
POLLFREQ 5
POLLFREQALERT 5
HOSTSYNC 15
DEADTIME 15
POWERDOWNFLAG /etc/killpower
NOTIFYFLAG ONBATT SYSLOG+WALL+EXEC
NOTIFYFLAG ONLINE SYSLOG+WALL+EXEC
NOTIFYCMD "/etc/ups/shutdown-script"
RBWARNTIME 43200
NOCOMMWARNTIME 300
FINALDELAY 5

# grep -v '^#' /etc/ups/upsd.users | egrep -v '^$'
[monuser]
password=pass
upsmon master

At this point, UPS should respond via USB which you can check with:

# usbhid-ups -DDD -a eaton3s

Make sure to replace “pass” with some password in both files. Now, the power outage script is where you can implement what you want. In my case, I want to see desktop notification every 10 seconds and after 3 minutes I want my system to poweroff:

# cat /etc/ups/shutdown-script
#!/bin/bash
PATH=/sbin:/usr/sbin:/bin:/usr/bin:/usr/local/sbin:/usr/local/bin

trap "exit 0" SIGTERM

notify() {
        notify-send -u $2 "$0: $1"
}

if [ "$NOTIFYTYPE" = "ONLINE" ]; then
        notify "power restored" critical
        killall -s SIGTERM `basename $0`
fi

if [ "$NOTIFYTYPE" = "ONBATT" ]; then
        notify "3 minutes until shutdown" critical
        let "n = 18"
        while [ $n -ne 0 ]
        do
                sleep 10
                let "n--"
                notify "$(( $n * 10 )) seconds until to shutdown" low
        done
        notify "commencing shutdown" critical
        upsmon -c fsd
fi

On server systems, you want to replace notify-send with probably something like echo $0: $1 | wall to notify console users. Make sure the script is executable:

# chmod +x /etc/ups/shutdown-script

Start the services, note that one of the three services (nut-driver) is started automatically as a dependency so do not enable it (systemd would complain anyway):

# systemctl start nut-monitor nut-server
# systemctl enable nut-driver nut-monitor nut-server
# systemctl status nut-driver nut-monitor nut-server

To diplay battery remaining capacity and other details you can use this command line tool:

# upsc eaton3s
Init SSL without certificate database
battery.charge: 96
battery.charge.low: 20
battery.runtime: 672
battery.type: PbAc
device.mfr: EATON
device.model: Eaton 3S 550
device.serial: 000000000
device.type: ups
driver.name: usbhid-ups
driver.parameter.pollfreq: 30
driver.parameter.pollinterval: 2
driver.parameter.port: auto
driver.parameter.synchronous: no
driver.version: 2.7.4
driver.version.data: MGE HID 1.39
driver.version.internal: 0.41
input.transfer.high: 264
input.transfer.low: 184
outlet.1.desc: PowerShare Outlet 1
outlet.1.id: 2
outlet.1.status: on
outlet.1.switchable: yes
outlet.2.desc: PowerShare Outlet 2
outlet.2.id: 3
outlet.2.status: off
outlet.2.switchable: yes
outlet.desc: Main Outlet
outlet.id: 1
outlet.switchable: no
output.frequency.nominal: 50
output.voltage: 230.0
output.voltage.nominal: 230
ups.beeper.status: enabled
ups.delay.shutdown: 20
ups.delay.start: 30
ups.firmware: 02
ups.load: 30
ups.mfr: EATON
ups.model: Eaton 3S 550
ups.power.nominal: 550
ups.productid: ffff
ups.serial: 000000000
ups.status: OL
ups.timer.shutdown: 0
ups.timer.start: 0
ups.vendorid: 0463

Interesting parameters which are worth putting onto my i3status bar are probably battery.* and ups.load. Remember to perform a test! A good one is checking if this command works fine:

# upsmon -c fsd

And then full “integration” test - exit all programs and then pull the wire off the wall and wait :-)

Good luck!