This image provides a complete UPS monitoring service (USB driver only).
This is a fork of sudo-bot/nut-upsd.
I added a lot of additional configuration options and implemented email notifications.
I use Debian instead of Alpine as base image to allow shutdown of the host machine using systemctl.

You can mount your own /etc/nut/ups.conf, /etc/nut/upsd.conf, /etc/nut/upsd.users and /etc/nut/upsmon.conf.
If not provided externally by bind mount, the configuration files are generated automatically using the following environment variables.

• UPS_NAME - Name of the UPS (default: ups)

• UPS_DESCRIPTION - Short description of the UPS (default: UPS)

• UPS_DRIVER - The driver to use for the UPS (default: usbhid-ups)

• UPS_PORT - The serial port where the UPS is connected (default: auto)

• LOWBATT_PERCENT - Override the percentage which is reported as low battery (and triggers SHUTDOWNCMD)

• LOWBATT_RUNTIME - Override the remaining runtime (in seconds) which is considered low (and triggers SHUTDOWNCMD)

• API_ADDRESS - The address used by upsd (default: 0.0.0.0)

• API_PORT - The port used by upsd (default: 3493)

• API_USER - The username for upsd (default: upsmon)

• API_PASSWORD - The username for upsd (default: random)

• ADMIN_PASSWORD - The username for the upsd admin user (default: random)

You can set any directive from uspmon.conf as an environment variable (Documentation) e.g. POLLFREQ or SHUTDOWNCMD.

If your host machine uses systemd (most distributions), you can shutdown the host from within the container using systemctl.
In this case, you have to mount /run/systemd from the host to the container and set e.g. SHUTDOWNCMD="systemctl poweroff".
In some cases, you need to mount /run/dbus, too.

You have to configure at least these options to enable email notifications:

• NOTIFICATION_EMAIL - Notification emails are sent to this email adress.

• NOTIFICATION_FROM - Email address from which the emails are sent

• NOTIFICATION_FROM_NAME - The display name of the email sender (default: $UPS_DESCRIPTION)

By default, you get notifications for all upsmon events.
You can disable emails for a certain event type by setting the environment variable NOTIFY_<type> to 0, e.g. NOTIFY_LOWBATT=0 (types under 'NOTIFYMSG' in Documentation).

The file /etc/nut/email_messages.json contains the subjects and messages of the notification emails.
You can provide your own messages by mounting your own file.

You have to set your smtp server by either providing /etc/msmtprc or using the following environment variables:

• SMTP_HOST - Hostname of the SMTP server

• SMTP_PORT - Port of the SMTP server (default: 587)

• SMTP_AUTH - Enable/disable user authentication (on/off, default: on)

• SMTP_USER - Username/email for authentication (default: $NOTIFICATION_FROM)

• SMTP_PASSWORD - Password for authentication

• SMTP_TLS - Enable/disable TLS (on/off, default: on)

• SMTP_STARTTLS - Enable/disable STARTTLS (on/off, default: on)

• SMTP_CERTCHECK - Enable/disable certificate verification (on/off, default: on)

A sample docker run command could look like this:

docker run -d \
    --name nut-upsd \
    --device /dev/bus/usb/xxx/yyy
    -p 3493:3493 \
    -e UPS_DESCRIPTION="My UPS" \
    -e POLLFREQ=10 \
    -e NOTIFY_NOCOMM=0 \
    -e NOTIFICATION_EMAIL="[email protected]" \
    -e NOTIFICATION_FROM="[email protected]" \
    -e SMTP_HOST="smtp.example.com" \
    -e SMTP_PASSWORD="xxxx" \
    schmailzl/nut-upsd

A sample docker-compose.yml could look like this:

version: '3'
services:
  nut:
    image: schmailzl/nut-upsd
    devices:
      - "/dev/bus/usb/xxx/yyy"
    ports:
      - "3493:3493"
    environment:
      UPS_DESCRIPTION: "My UPS"
      POLLFREQ: 10
      NOTIFY_NOCOMM: 0
      NOTIFICATION_EMAIL: [email protected]
      NOTIFICATION_FROM: [email protected]
      SMTP_HOST: smtp.example.com
      SMTP_PASSWORD: xxxx