Yunomdns Doesn't Apply on Boot

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1

What type of hardware are you using: Old laptop or computer
What YunoHost version are you running: 12.1.39 (stable)
How are you able to access your server: The webadmin
SSH
Are you in a special context or did you perform specific tweaking on your YunoHost instance ?: Nothing, exept a likely unrelated botched Vaultwarden install around the time this started (it had authenticaion issues so I uninstalled it).

Describe your issue

I had a lot typed up about what I’m trying to do, but it deleted everything because I put a link in this post, and I don’t want to type that all again. Long story short:
yunomdns starts but doesn’t add .local domains to the network.
I have tried everything these forum posts have suggested, including permissions stuff, but nothing has fixed the issue.
I still have to manually run sudo systemctl restart yunomdns every boot in order to get the .local domains to register on the network.

Share relevant logs or error messages

The diagnostics provided by yunopaste say everything is fine. I can’t link to it though since it’ll delete everything I’ve written again.

Systemctl logs show something interesting. When yunomdns is started on boot, it only starts 1 Task, but when it’s restarted (or started) manually, it starts 2 tasks and has logs saying that individual domains were added to the Ethernet interface.

neurodb_admin@neurodb:~$ sudo systemctl status yunomdns
[sudo] password for neurodb_admin: 
● yunomdns.service - YunoHost mDNS service
     Loaded: loaded (/etc/systemd/system/yunomdns.service; enabled; preset: enabled)
     Active: active (running) since Wed 2026-02-11 18:27:12 CST; 1min 18s ago
   Main PID: 673 (python3)
      Tasks: 1 (limit: 18846)
     Memory: 15.9M
        CPU: 115ms
     CGroup: /system.slice/yunomdns.service
             └─673 python3 /usr/bin/yunomdns

Feb 11 18:27:12 neurodb.local systemd[1]: Started yunomdns.service - YunoHost mDNS service.
Feb 11 18:27:14 neurodb.local yunomdns[673]: Registering...
Feb 11 18:27:14 neurodb.local yunomdns[673]: Registered. Press Ctrl+C or stop service to stop.
neurodb_admin@neurodb:~$ sudo systemctl restart yunomdns
neurodb_admin@neurodb:~$ sudo systemctl status yunomdns
● yunomdns.service - YunoHost mDNS service
     Loaded: loaded (/etc/systemd/system/yunomdns.service; enabled; preset: enabled)
     Active: active (running) since Wed 2026-02-11 18:30:02 CST; 51s ago
   Main PID: 1393 (python3)
      Tasks: 2 (limit: 18846)
     Memory: 13.3M
        CPU: 158ms
     CGroup: /system.slice/yunomdns.service
             └─1393 python3 /usr/bin/yunomdns

Feb 11 18:30:02 neurodb.local systemd[1]: Started yunomdns.service - YunoHost mDNS service.
Feb 11 18:30:04 neurodb.local yunomdns[1393]: Adding <redacted>.local with addresses ['<redacted>'] on interface enp1s0
Feb 11 18:30:04 neurodb.local yunomdns[1393]: Adding <redacted>.local with addresses ['<redacted>'] on interface enp1s0
Feb 11 18:30:04 neurodb.local yunomdns[1393]: Adding <redacted>.local with addresses ['<redacted>'] on interface enp1s0
Feb 11 18:30:04 neurodb.local yunomdns[1393]: Registering...
Feb 11 18:30:06 neurodb.local yunomdns[1393]: Registered. Press Ctrl+C or stop service to stop.
neurodb_admin@neurodb:~$
2

Hello !

Got also an issue with yunomdns which happen to bug when I tried to update my clientvpn app.


journalctl: 
  - Jan 25 10:43:41 yunomdns[1306]: Registering...
  - Jan 25 10:43:42 yunomdns[1306]: Registered. Press Ctrl+C or stop service to stop.
  - Feb 16 12:57:15 systemd[1]: Stopping yunomdns.service - YunoHost mDNS service...
  - Feb 16 12:57:15 systemd[1]: yunomdns.service: Deactivated successfully.
  - Feb 16 12:57:15 systemd[1]: Stopped yunomdns.service - YunoHost mDNS service.
  - Feb 16 12:57:15 systemd[1]: yunomdns.service: Consumed 1h 4min 22.915s CPU time.
  - -- Boot 4b4c41e952ed47659c8b6a2e4cb38267 --
  - Feb 16 13:06:03 systemd[1]: Started yunomdns.service - YunoHost mDNS service.
  - Feb 16 13:06:04 yunomdns[1438]: Traceback (most recent call last):
  - Feb 16 13:06:04 yunomdns[1438]:   File "/usr/bin/yunomdns", line 205, in <module>
  - Feb 16 13:06:04 yunomdns[1438]:     sys.exit(0 if main() else 1)
  - Feb 16 13:06:04 yunomdns[1438]:                   ^^^^^^
  - Feb 16 13:06:04 yunomdns[1438]:   File "/usr/bin/yunomdns", line 86, in main
  - Feb 16 13:06:04 yunomdns[1438]:     with open("/etc/yunohost/mdns.yml", "r") as f:
  - Feb 16 13:06:04 yunomdns[1438]:          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  - Feb 16 13:06:04 yunomdns[1438]: PermissionError: [Errno 13] Permission denied: '/etc/yunohost/mdns.yml'
  - Feb 16 13:06:04 systemd[1]: yunomdns.service: Main process exited, code=exited, status=1/FAILURE
  - Feb 16 13:06:04 systemd[1]: yunomdns.service: Failed with result 'exit-code'.
  - Feb 16 14:25:41 systemd[1]: Started yunomdns.service - YunoHost mDNS service.
  - Feb 16 14:25:41 yunomdns[4212]: Traceback (most recent call last):
  - Feb 16 14:25:41 yunomdns[4212]:   File "/usr/bin/yunomdns", line 205, in <module>
  - Feb 16 14:25:41 yunomdns[4212]:     sys.exit(0 if main() else 1)
  - Feb 16 14:25:41 yunomdns[4212]:                   ^^^^^^
  - Feb 16 14:25:41 yunomdns[4212]:   File "/usr/bin/yunomdns", line 86, in main
  - Feb 16 14:25:41 yunomdns[4212]:     with open("/etc/yunohost/mdns.yml", "r") as f:
  - Feb 16 14:25:41 yunomdns[4212]:          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  - Feb 16 14:25:41 yunomdns[4212]: PermissionError: [Errno 13] Permission denied: '/etc/yunohost/mdns.yml'
  - Feb 16 14:25:41 systemd[1]: yunomdns.service: Main process exited, code=exited, status=1/FAILURE
  - Feb 16 14:25:41 systemd[1]: yunomdns.service: Failed with result 'exit-code'.
  - -- Boot c2ee6a40504e4420bdd004fb0757d5e8 --
  - Feb 16 14:33:33 systemd[1]: Started yunomdns.service - YunoHost mDNS service.
  - Feb 16 14:33:36 yunomdns[1323]: Traceback (most recent call last):
  - Feb 16 14:33:36 yunomdns[1323]:   File "/usr/bin/yunomdns", line 205, in <module>
  - Feb 16 14:33:36 yunomdns[1323]:     sys.exit(0 if main() else 1)
  - Feb 16 14:33:36 yunomdns[1323]:                   ^^^^^^
  - Feb 16 14:33:36 yunomdns[1323]:   File "/usr/bin/yunomdns", line 86, in main
  - Feb 16 14:33:36 yunomdns[1323]:     with open("/etc/yunohost/mdns.yml", "r") as f:
  - Feb 16 14:33:36 yunomdns[1323]:          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  - Feb 16 14:33:36 yunomdns[1323]: PermissionError: [Errno 13] Permission denied: '/etc/yunohost/mdns.yml'
  - Feb 16 14:33:36 systemd[1]: yunomdns.service: Main process exited, code=exited, status=1/FAILURE
  - Feb 16 14:33:36 systemd[1]: yunomdns.service: Failed with result 'exit-code'.
  - Feb 16 14:38:14 systemd[1]: Started yunomdns.service - YunoHost mDNS service.
  - Feb 16 14:38:14 yunomdns[2724]: Traceback (most recent call last):
  - Feb 16 14:38:14 yunomdns[2724]:   File "/usr/bin/yunomdns", line 205, in <module>
  - Feb 16 14:38:14 yunomdns[2724]:     sys.exit(0 if main() else 1)
  - Feb 16 14:38:14 yunomdns[2724]:                   ^^^^^^
  - Feb 16 14:38:14 yunomdns[2724]:   File "/usr/bin/yunomdns", line 86, in main
  - Feb 16 14:38:14 yunomdns[2724]:     with open("/etc/yunohost/mdns.yml", "r") as f:
  - Feb 16 14:38:14 yunomdns[2724]:          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  - Feb 16 14:38:14 yunomdns[2724]: PermissionError: [Errno 13] Permission denied: '/etc/yunohost/mdns.yml'
  - Feb 16 14:38:14 systemd[1]: yunomdns.service: Main process exited, code=exited, status=1/FAILURE
  - Feb 16 14:38:14 systemd[1]: yunomdns.service: Failed with result 'exit-code'.

Here’s the log.

The status

 × yunomdns.service - YunoHost mDNS service
Loaded: loaded (/etc/systemd/system/yunomdns.service; enabled; preset: enabled)
Active: failed (Result: exit-code) since Tue 2026-02-17 20:14:19 GMT; 3min 47s ago
Duration: 454ms
Process: 65351 ExecStart=/usr/bin/yunomdns (code=exited, status=1/FAILURE)
Main PID: 65351 (code=exited, status=1/FAILURE)
CPU: 444ms

Feb 17 20:14:19 florentcurk.com yunomdns[65351]: Traceback (most recent call last):
Feb 17 20:14:19 florentcurk.com yunomdns[65351]:   File “/usr/bin/yunomdns”, line 205, in 
Feb 17 20:14:19 florentcurk.com yunomdns[65351]:     sys.exit(0 if main() else 1)
Feb 17 20:14:19 florentcurk.com yunomdns[65351]:                   ^^^^^^
Feb 17 20:14:19 florentcurk.com yunomdns[65351]:   File “/usr/bin/yunomdns”, line 86, in main
Feb 17 20:14:19 florentcurk.com yunomdns[65351]:     with open(“/etc/yunohost/mdns.yml”, “r”) as f:
Feb 17 20:14:19 florentcurk.com yunomdns[65351]:          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Feb 17 20:14:19 florentcurk.com yunomdns[65351]: PermissionError: [Errno 13] Permission denied: ‘/etc/yunohost/mdns.yml’
Feb 17 20:14:19 florentcurk.com systemd[1]: yunomdns.service: Main process exited, code=exited, status=1/FAILURE
Feb 17 20:14:19 florentcurk.com systemd[1]: yunomdns.service: Failed with result ‘exit-code’.
3

I have the same error on one of my servers for a few days, where you able to solve it ?

4

Hey !

nop. I haven’t try much as I don’t understand what the heck. And also it’s not doing anything bad on the server… but I’d like to solve it if I can

5

I made a workaround using cron:

Run sudo crontab -e to open the root crontab file
Add the line @reboot sleep 30 && systemctl restart yunomdns to the end of the file.
Restart your Yunohost instance.

That should avoid the issue, though it’s by no means ideal and I hope for a proper fix to Yunohost.

1 Like
6

That didn’t work for me.
I solved by running ‘sudo chown mdns:mdns /etc/yunohost/mdns.yml’

and then restart the service again.