APCUPSd-Docker

This Docker container connects to the local APC UPS or a remote apcupsd instance. Even if running in a container it can notify the host and trigger shutdown (or other) actions, if needed. All without special privileges.

It can also be used for any other arbitrary commands and every apcupsd trigger action.

See Configuration Example below.

Requirements

• Bash

Usage

With default example settings:

docker run -t -v /tmp/apcupsd-docker:/tmp/apcupsd-docker gersilex/apcupsd

With custom settings:

• Clone or download the content of this repository
• Copy apcupsd.conf and make your changes
• Repeat with doshutdown and/or host-trigger-check.sh
• Run the container and map the files into the container to override the default settings:

docker run -t \
  -v /tmp/apcupsd-docker:/tmp/apcupsd-docker \
  -v /path/to/your/apcupsd.conf:/etc/apcupsd/apcupsd.conf \
  -v /path/to/your/doshutdown:/etc/apcupsd/doshutdown \
  gersilex/apcupsd

You can read the status from the stdout output, as the container starts apcupsd -b and shows INFO loglevel information.

The /etc/apcupsd/doshutdown script will be executed when a condition (Low Battery, Low Lifetime left, Timeout exceeded) is reached while being in battery operation (See /etc/apcupsd/apcupsd.conf for more information and tweaking).

To be able to signal the Docker host on which the container runs, you should either map your local device into the container (if the UPS is connected to this host) or map a folder from your host into the container and use the included doshutdown script. The script will write a 1 into a file with the name trigger in that folder. Monitor it on the host with cron or inotify and gracefully shut down your server, when the content is 1. Don't forget to remove the file before shutdown to omit shutdown-loops after booting again.

The host-trigger-check.sh contains a cron-compatible script that will run an included bash function, if it reads a '1' in the /tmp/apcupsd-docker/trigger file on the host. Read the shell script for instructions on how to use it. It's recommended to run this every minute.

Configuration Example

An example apcupsd.conf file is provided, along with the original comments. Minimal working example:

• UPS connected to a remote apcupsd instance on the host nas. Will execute doshutdown if 5% battery is left or 10 minutes remaining. Docker host has cron running and checks for shutdown flag every minute.

# /etc/apcupsd/apcupsd.conf

UPSTYPE net
DEVICE nas:3551
BATTERYLEVEL 5
MINUTES 10

# /root/apcupsd/host-trigger-check.sh (excerpt)
[...]

TRIGGERFILE="/tmp/apcupsd-docker/trigger"

# Put everything you want to do on a shutdown condition instide this function.
action(){
  echo "Detected '1' in '$TRIGGERFILE'."

  # Plan shutdown in 5 minutes
  shutdown -P +5

  echo "Stopping all Docker containers..."
  docker ps -q | xargs --no-run-if-empty docker stop --time 300

  # Shutdown now, if we finish early with previous command
  shutdown -P now
}

[...]

# /var/spool/cron/gersilex (generated by 'crontab -e')

* * * * * /root/apcupsd/host-trigger-check.sh

FAQ

Q: I can't see any log output. A: Allocate a tty (with docker run -t). Apcupsd only shows output to ttys.

Q: I only see NIS server startup succeeded A: If there is no new log line after 60 seconds, it probably is just fine. apcupsd does not log successful connections. Use apcaccess to be sure:

Q: How to see if it works? A: Run docker exec -it <container-name> apcaccess and watch the output.

License

MIT