[SOLVED] Problem running EXEC command to shutdown Synology Diskstation via SSH

Add-ons Bindings
1

Hello community,

after setting up scripts and items to start and shut down my Windows PC, I wanted to do the same with my Synology Diskstation.

As preparation, I made sure that user “Openhabian” can ssh to the Diskstation and login there as root without password using keys (setting up keys, put them in Synology’s authorized_keys file). With the following command, user “Openhabian” can connect to my Synology as root:

[16:12:14] openhabian@openHABianPi:~$ ssh root@192.168.75.10 -i /home/openhabian/.ssh/id_rsa_root
root@DiskStation:~#

Next, I extended the command to shutdown diskstation:

[16:18:36] openhabian@openHABianPi:~$ ssh root@192.168.75.10 -i /home/openhabian/.ssh/id_rsa_root sudo poweroff

After issuing this command, the Diskstation starts to shutdown. Everything ok so far.

Next, I set up a thing with EXEC command, containing the very same ssh-command:

Thing exec:command:synooff [command="ssh root@192.168.75.10 -i /home/openhabian/.ssh/id_rsa_root sudo poweroff", interval=0, autorun=false]

Items:

Switch 			Presence_DiskStation		"DiskStation" 				<network> 	{channel="network:pingdevice:192_168_75_10:online" }
Switch			Synology_ON_OFF				"Synology"					<network>   ["Switchable"]
Switch 			Synology_ON					"Synology ON"				<network>	{wol="192.168.75.255#00:11:32:2D:94:C5" }
Switch 			Synology_OFF 				"Synology OFF" 							{channel="exec:command:synooff:run" }

Rules:

rule "Synology onoff"

when Item Synology_ON_OFF received command
then switch (receivedCommand)
	{
	case ON: { 
	Synology_ON.sendCommand(ON)
	logInfo("default.rules", "Synology_ON.SendCommand(ON) executed")
	}
    case OFF: { 
	Synology_OFF.sendCommand(ON)
	logInfo("default.rules", "Synology_OFF.SendCommand(ON) executed")	}
	}
end

Sitemap:

Switch item=Synology_ON_OFF label="Synology Diskstation"

Log-Output when switching off:

2018-12-16 16:09:33.395 [INFO ] [smarthome.model.script.default.rules] - Synology_OFF.SendCommand(ON) executed

So I can see in the log that the command was running, but the Synology does not shut down. The WOL does work, by the way.

Now I wonder why the command

ssh root@192.168.75.10 -i /home/openhabian/.ssh/id_rsa_root sudo poweroff

is working when issued as user “Openhabian” on the command line, but not when used with the EXEC-Binding. The EXEC-Bindung itself is working, because my command for shutting down Windoes by net rpc shutdown works fine.

Any ideas?

2

No expert here, but did you try to experiment with your interval and timeout settings? Maybe remove the interval and include a timeout of 5000

3

I think this posting led me on the right way:

I think my mistake is:

I mixed users “openhabian” and “openhab”. The user the exec-binding is using is indeed “openhab”, not “openhabian”. So I have to make sure ssh works for user openhab. I will try to change configs and report.

4

My assumption was right. To make things work, I had to to the following:

Make the public key of the destination known to user openhab by

sudo -u openhab /usr/bin/ssh root@192.168.75.10

and answering “yes”.

Copy the private keyfile to /var/lib/openhab2/.ssh/ and change ownership to openhab:

cd /home/openhabian/.ssh
sudo cp id_rsa_root /var/lib/openhab2/.ssh
sudo chown openhab id_rsa_root
sudo chgrp openhab id_rsa_root

Then, change the .things accordingly:

Thing exec:command:synooff [command="ssh root@192.168.75.10 -i /var/lib/openhab2/.ssh/id_rsa_root sudo poweroff", interval=0, timeout=30, autorun=false]

Now everything works fine, and I will never forget that EXEC-commands run under user “openhab” and NOT “openhabian” :wink: