Wake On Lan - For those running home assistant in docker

Share your Projects!
14

I wanted to post my reply in this old thread to share my solution to this, mainly because this was my first hit when searching for a solution to wake-on-lan from Docker.

I don’t want to use host network, and I was reluctant to use the ssh solution presented here (good effort and documentation though!).

My solution was to use named pipe, inspired by this answer from Stackoverflow
I also took inspiration from this thread with how to structure the switch on_command.

I had never used named pipes prior to this, so I won’t go into detail how they work. See the Stackoverflow post above for some more explanation, or do a quick google.
For our purposes, they are a way of passing information from docker to the controlling host. We will use the ability of wakeonlan to read the mac-adress from a file, that file will be our named pipe which will just be waiting for us to input the mac-adress to it.

Howto (tested on Ubuntu Server 18.04)
Install wakeonlan if you don’t have it already
sudo apt install wakeonlan

Create a named pipe. You can create it anywhere. If you choose a new location you must expose that location to your home assistant container.
I found it simplest to just create the pipe in home assistants config directory, remember to change the path to your own:
sudo mkfifo /path/to/homeassistant/config/wolpipe

Normally the pipe would be created with correct permission, to set them properly just in case use the command below (probably optional):
sudo chmod 644 /path/to/homeassistant/config/wolpipe

Create a systemd-service to continously listen for WOL-requests from the named pipe.
Remember to change the path to your homeassistant config directory.
Note that the service will be running as user nobody which should severely limit what a potential attacker could do on your docker host even if attacker gains access to your docker container

sudo cat > /etc/systemd/system/docker-wol.service << EOF
[Unit]
Description=Listen for wake-on-lan from docker via pipe

[Service]
Restart=always
User=nobody
Group=nogroup
ExecStart=/usr/bin/wakeonlan -f /path/to/homeassistant/config/wolpipe

[Install]
WantedBy=multi-user.target
EOF

Reload systemd, start the service and set the service to start on boot (if that’s what you want)

sudo systemctl daemon-reload
sudo systemctl start docker-wol
sudo systemctl enable docker-wol

At this point you should be able to send the mac-adress through the pipe and have your appliance turn on, to test:
sudo echo 'ma:ca:dd:re:ss' > /path/to/homeassistant/config/wolpipe

To verify, check your appliance and the logs of the service you created
journalctl -fu docker-wol

If you repeat the above test it should keep working since systemd restarts the command everytime it completes.

Now you can do the same thing from inside the home-assistant docker container.
To test communication from inside docker, get a shell on the container:
docker exec -it homeassistant bash

Run the same echo command there but use the path inside the container:
echo 'ma:ca:dd:re:ss' > /config/wolpipe

It should still work.

Finally some inspiration to what I did to get my LG WebOS TV to work with wake-on-lan from docker, in configuration.yaml (Edited for version 2022.2.0)

#wake_on_lan: # Home assistant wol support not needed anymore

webostv:
  host: !secret tvrum_ip
  name: TV-rum
  customize:
    sources:
      - MySources

shell_command:
  tvrum_wol: !secret tvrum_command_on

# Either put this here or in your automations.yaml
automation:
  - id: 'tvrum_wol'
    trigger:
      - platform: webostv.turn_on
        entity_id: media_player.tv_rum
    action:
      - service: shell_command.tvrum_wol

media_player:

Then in secrets.yaml I put the entire command line (note that we’re using the path inside the docker container here):

tvrum_command_on: "/bin/echo 'ma:ca:dd:re:ss' > /config/wolpipe"
other_secrets: 123456

Good luck, hope this helps anyone.

7 Likes