Hi,
You can install a nut on a raspberry pi and connect a UPS through usb to raspberry. Video:
https://www.youtube.com/watch?v=vyBP7wpN72c&t=1645s
If a help is needed with any part, do not hesitate to ask.
I was able to set up Home assistant as the docker container on a raspberry Pi and add my Green Cell UPS there - actually Home Assistant detected it automatically.
I see basic information like load, power etc. I had to do that because I am using AdGuard Home on a raspberry and I was not able to run it together. The Home Assistant is working locally so, I had to create a ssh tunnel to be able to access it from my laptop.
I had to change the driver to nutdrv_qx and modify a little bit the ups.conf to be able to work with the mentioned UPS. Finally I have it working and the Raspberry Pi is shutting down as it should. Early shutdown I set to 180 seconds. Now it is time to write a bash script that will log into Mikrotik router and perform the shutdown command before the raspberry will shut down. I will use a bash script that I tested on my Mikrotik hap ac2.
#!/bin/bash
# The result of the script execution is recorded in the mikrotik.log located in the /root directory.
LOG_FILE=/root/mikrotik.log
exec 3>&1 4>&2
trap 'exec 2>&4 1>&3' 0 1 2 3
exec 1>${LOG_FILE} 2>&1
data=$( date +"%Y-%m-%d %H:%M:%S" )
nutlog=/var/log/nut.log
if [ "`grep "Mikrotik" "$nutlog"`" ]; then
echo "$data -> Mikrotik router will go down."
echo "UPS is down!" | mail -s "UPS ALERT DOWN" admin@example.com -A /root/mikrotik.log
echo "UPS is down!" | mail -s "UPS ALERT DOWN" youremail@gmail.com -A /root/mikrotik.log
rm -f $nutlog
touch $nutlog
chown root:adm $nutlog
chmod 640 $nutlog
systemctl restart rsyslog
sshpass -f /root/creds ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -o CheckHostIP=no -p 2244 nut@192.168.88.1 "/system shutdown; /y; /quit;"
exit
else
echo "$data -> Mikrotik router will remain powered on."
exit
fi
Of course sshpass has to be installed with the below command
-p 2244 is a nonstandard ssh port
I created a nut user on a mikrotik and additionally tested it with RSA keys without a passphrase what in LAN is let's say secure enough. All you have to do is to save private and public key in openSSH format, but not the newest one, but instead the standard format - hope I explained it well, just because Puttygen allow syou to save the RSA key in new openSSH format. Anyway you have to upload the private key into the Files in mikrotik, and then in system - users section im port the key for a user. But you can also just use ordinary password with sshpass as I did in the password. If yopu want use RSA, you have to remove this from bash script: spawn sshpass -f /root/creds
Then you have to add the below line to crontab for root account but it can be also a pi user and it will run every two minutes.
*/2 * * * * root /root/mikrotik.sh
*/2 * * * * pi /home/pi/mikrotik.sh
The default system logger is rsyslog. Add the following to /etc/rsyslog.d/99-nut.conf
:syslogtag,contains,"upsmon" /var/log/nut.log
:syslogtag,contains,"nut" /var/log/nut.log
:syslogtag,contains,"upssched" /var/log/nut.log
Then perform the below commands:
touch /var/log/nut.log
chown root:adm /var/log/nut.log
chmod 640 /var/log/nut.log
systemctl restart rsyslog
All the nut logs will go there.
In the file /etc/nut/upssched.conf I defined below actions
AT ONBATT * START-TIMER onbatt 300
AT ONLINE * CANCEL-TIMER onbatt online
AT ONBATT * START-TIMER earlyshutdown 180
AT ONLINE * CANCEL-TIMER earlyshutdown
AT LOWBATT * START-TIMER shutdowncritical 30
AT ONLINE * CANCEL-TIMER shutdowncritical
AT COMMBAD * START-TIMER commbad 30
AT COMMOK * CANCEL-TIMER commbad commok
AT REPLBATT * EXECUTE replacebatt
And the /bin/upssched-cmd file contains the below:
case $1 in
onbatt)
logger -t upssched-cmd "The UPS is on battery"
;;
online)
logger -t upssched-cmd "The UPS is back on power"
;;
commbad)
logger -t upssched-cmd "The server lost communication with UPS"
;;
commok)
logger -t upssched-cmd "The server re-establish communication with UPS"
;;
earlyshutdown)
logger -t upssched-cmd "UPS on battery too long, forced Mikrotik shutdown"
;;
shutdowncritical)
logger -t upssched-cmd "UPS on battery critical, forced shutdown"
/usr/sbin/upsmon -c fsd
;;
upsgone)
logger -t upssched-cmd "The UPS has been gone for awhile"
;;
replacebatt)
logger -t upssched-cmd "The UPS needs new battery"
;;
*)
logger -t upssched-cmd "Unrecognized command: $1"
;;
esac
My bash script catches the Mikrotik phrase from the log. I had to test it to be sure for 100% it is working as expected.
Sending e-mails
Log as root with the below command
Install th below tools:
apt install ssmtp mailutils
Edit configurtation file, to be able to send e-mails with gmail:
nano /etc/ssmtp/ssmtp.conf
Set as below:
root=postmaster
mailhub=smtp.gmail.com:587
rewriteDomain=
hostname=yourhostname ##for example raspberrypi
UseSTARTTLS=YES
AuthUser=youremailaddress@gmail.com
AuthPass=google_mail_application_password
FromLineOverride=YES
Not the mail password for your gmail. So, you have to generate application password. Guide:
https://support.google.com/mail/answer/185833?hl=en
Create emailnotify.sh in /root
Put into the file the below:
#!/bin/bash
sleep 60
IP=`hostname -i`
# Or you can comment the above and uncomment the below. In my case it presented the localhost IP address instead the IP from eth0 interface
# IP=`echo $(ifconfig eth0 | grep 'inet' | cut -d: -f2 | awk '{ print $2}')`
HOSTNAME=`hostname -f`
echo "$HOSTNAME online. IP address: $IP" > /root/email.txt
echo >> /root/email.txt
date >> /root/email.txt
mail -s "$HOSTNAME online" -r raspberrypi@localhost yourmail@example.com < /root/email.txt
mail -s "$HOSTNAME online" -r raspberrypi@localhost yourmail@gmail.com < /root/email.txt
rm -rf /root/email.txt
Then set it as executable
Then edit crontab
and add the below entry:
@reboot /root/emailnotify.sh
Now if the UPS will go down you will be notified and also when the raspberry pi will boot up.
