systemctl, how to unmask

Question

root@gcomputer:~# systemctl status x11-common
● x11-common.service
   Loaded: masked (/dev/null; bad)
   Active: inactive (dead)

I tried systemctl unmask x11-common and systemctl unmask x11-common.service but that did not change anything.

How do I unmask it?

Answer 1

The commands you are using are both correct. See also the manual.

It seems the unmask command fails when there is no existing unit file in the system other than the symlink to /dev/null. If you mask a service, then that creates a new symlink to /dev/null in /etc/systemd/system where systemd looks for unit files to load at boot. In this case, there is no real unit file.

Others seem to have similar issues

x11-common.service was also masked on my system. You can fix it like this:

First check that the unit file is a symlink to /dev/null

file /lib/systemd/system/x11-common.service

it should return:

/lib/systemd/system/x11-common.service: symbolic link to /dev/null

in which case, delete it

sudo rm /lib/systemd/system/x11-common.service

Since you changed a unit file, you need to run this:

sudo systemctl daemon-reload

now check the status:

systemctl status x11-common

if it doesn't say loaded and running (if the circle is still red), reinstall the package:

sudo apt-get install --reinstall x11-common

and reload the daemon again

sudo systemctl daemon-reload

and check status once more

systemctl status x11-common

Now it's green and running :) The service has no systemd unit file, but systemd happily uses the script for it in /etc/init.d instead.

Answer 2

Here I show how I remove the mask using systemctl

$ sudo systemctl status bluetooth.service
● bluetooth.service
     Loaded: masked (Reason: Unit bluetooth.service is masked.)
     Active: inactive (dead)

$ sudo systemctl unmask bluetooth.service
Removed /etc/systemd/system/bluetooth.service.

$ sudo systemctl status bluetooth.service
● bluetooth.service - Bluetooth service
     Loaded: loaded (/lib/systemd/system/bluetooth.service; disabled; vendor preset: e>
     Active: inactive (dead)
       Docs: man:bluetoothd(8)

$ sudo systemctl start bluetooth.service

$ sudo systemctl status bluetooth.service
● bluetooth.service - Bluetooth service
     Loaded: loaded (/lib/systemd/system/bluetooth.service; disabled; vendor preset: e>
     Active: active (running) since Sat 2022-07-30 08:50:04 +06; 2s ago
       Docs: man:bluetoothd(8)
   Main PID: 23191 (bluetoothd)
     Status: "Running"
      Tasks: 1 (limit: 9135)
     Memory: 1.6M
     CGroup: /system.slice/bluetooth.service
             └─23191 /usr/lib/bluetooth/bluetoothd

Answer 3

Follow the steps below:

1. systemctl edit systemd-hostnamed

   Add the 2 lines below then exit the editor (don't forget to save when prompted):

   [Service]
   PrivateNetwork=no
   

2. This will create an override.conf file with the above 2 lines in the directory:

   /etc/systemd/system/systemd-hostnamed.service.d/
   

3. The update systemd:

   systemctl daemon-reload
   

4. Then restart the service:

   systemctl restart systemd-hostnamed
   

You should now be able to run hostnamectl without it hanging.

Answer 4

It could be your service has an empty override file, like this:

● redis-server.service - Advanced key-value store
   Loaded: loaded (/lib/systemd/system/redis-server.service; masked; vendor preset: enabled)
  Drop-In: /etc/systemd/system/redis-server.service.d
           └─limit.conf

Check if limit.conf is an empty file. If it is, please remove it. Then the service should be unmasked.