Power on and off Diskstation with Home Assistant

I use my Synology Diskstation mainly as a backup device. Therefore it does not need to run all the time. In the past I configured a "Power schedule" directly within the Diskstation. It would turn on at a certain time and power off every night. Now I wanted a smarter behaviour e.g. I would like to automatically turn on the Diskstation when I come home, so my Smartphone can backup data. Another example would be to power on the diskstation to store a Home Assistant Backup and afterwards power it off again. Also it would be nice if I could turn it off with my "good night"-Switch next to my bed. I achieved this by controlling the Diskstation via Home Assistant. This article describes the configuration steps, necessary for this.

Turn on Diskstation with Wake On Lan

We can use Wake on Lan to turn of the diskstation by a network message.

Diskstation configuration

First we need to enable Wake on Lan on our diskstation:

• Login into your Diskstation
• Go to Control Panel > Hardware & Power > General
• Under Power Recovery activate Enable WOL on Lan

After that you are able to start your Diskstation over the network. e.g. on a Mac you could run following command in the terminal:

# Install wakeonlan command via brew 
brew install wakeonlan
# Wake up diskstation by using its MAC Address
wakeonlan XX:XX:XX:XX:XX:XX

Note: For sending a magic package via wakeonlan you can specify an ip:

-i ip_address
        set the destination IP address
        default: 255.255.255.255 (the limited broadcast address)

This is NOT the ip-address of your device, this is the broadcast address. Your device is identified by the mac address.

Home Assistant Configuration

Now we need to send this magic package from Home Assistant. This can be done with the Wake on LAN integration. It allows to add a switch which sends the packages when it is turned on. We just need to supply the mac address of our diskstation in the configuration. My configuration looks like this:

switch:
  - platform: wake_on_lan
    mac: XX:XX:XX:XX:XX:XX
    host: "192.168.179.30"
    name: "Diskstation"

The host parameter contains the ip of the diskstation, so it can check if the diskstation is online or not. For more details see the integration documentation.

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Turn off Diskstation via ssh

To turn off the diskstation remotely we need to login via ssh and call the poweroff command. I used following steps:

1. Create HomeAssistant User on diskstation

First we need to create a new user on our diskstation:

• Create a user which can be used from home assistant to login to your diskstation

  • Login to Diskstation
  • Control Panel -> User -> Create -> Enter password, username, ...
  • Make sure to give the user adminstrator rights otherwise he cannot execute the poweroff command

2. Require no password for sudo poweroff

To shutdown the diskstation we use the command sudo poweroff. If you ssh with the new user to your diskstation and run it you would be asked to enter your password before the command is executed. When we run this command later using a script we cannot enter the password. Therefore we add following line to the end of /etc/sudoers:

home_assistant_ssh ALL=NOPASSWD: /sbin/poweroff

This will allow the user home_assistant_ssh to execute the poweroff command without entering a password.

3. Create keys on your Home Assistant device (e.g. Raspi)

Now we want to ssh into the dikstation from Home Assistant.

• Login to Home Assistant via ssh

  • If not already done configure SSH-Server Addon
  • ssh root@hassio.local

• Create keys in ~/.ssh

  • $homeassistant:ssh-keygen -t rsa -b 4096 -C "home_assistant@raspi"
  • do NOT set a password
  • make sure your private (id_rsa) and public key (id_rsa_pub) are generated in ls ~/.ssh

• Copy public key to diskstation

  • $homeassistant:ssh-copy-id -i .ssh/id_rsa.pub home_assistant_ssh@diskstation.local
  • this adds your public key to the authorized_keys file on your dikstation

  • Next we need to set the correct permission for the folder & files on the diskstation

    • $homeassistant:ssh USERNAME@DISKSTATION_IP - enter password
    • $diskstation:chmod 0711 ~
    • $diskstation:chmod 0711 ~/.ssh
    • $diskstation:chmod 0600 ~/.ssh/authorized_keys
    • $diskstation:exit
  • Now you should be able to login to the disktation from the Home Assistant shell without entering a password e.g. ssh USERNAME@DISKSTATION_IP

4. Copy ssh keys to configuration

Our keys created in 3 are not accessible by other integration e.g. the shell_command integration we will use later. Therefore we need to copy the ssh keys to the configuration folder.

cp ~/.ssh/id_rsa /config/.ssh
cp ~/.ssh/id_rsa.pub /config/.ssh

Make sure that you keep your private key (id_rsa) safe. e.g. take care when publishing your configuration online.

5. Call power off command from Home Assistant

After all the preperations in the previous steps we are now ready to shutdown the diskstation from home assisant by executing following command:

ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -i /config/.ssh/id_rsa home_assistant_ssh@192.168.179.30 sudo poweroff

To call this command from inside HomeAssistant we extend the wake_on_lan configuration by the turn_off parameter:

switch:
  - platform: wake_on_lan
    mac: ...
    host: "192.168.179.30"
    name: "Diskstation"
    turn_off:
        service: shell_command.power_off_diskstation
    
shell_command:
    power_off_diskstation: 'ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -i /config/.ssh/id_rsa home_assistant_ssh@192.168.179.30 sudo poweroff'

The switch will now ssh into the diskstation and call poweroff when it is turned off.

Final steps

And that's it. 😀

The switch now controls your diskstation. Of course you can use it as any other switch in the Lovelace UI. If you want to trigger it from code you can call the service homeassistant.turn_off with the entity, in my case entity_id: switch.diskstation.