How to Kill X service permanently in ubuntu server

Question

When I attempt to stop or kill the X service using the PID command on the Ubuntu server, it temporarily stops, but after a few minutes, it automatically appears again. It doesn't seem to work as expected. please suggest any way to resolve it.

Answer

Which process is it that you're trying to kill? If it's launched by a service that's under systemd control, then it may be set to automatically restart on failure.

This Red Hat document explains it in more depth, I know you're running Ubuntu but they both use systemd https://www.redhat.com/sysadmin/systemd-automate-recovery

Answer

X service is associated with graphical desktop environment for GUI. Your Ubuntu probably have GUI installed. 
If you do not need GUI, you can switch from graphical.target to multi-user. target with the command

```
sudo systemctl isolate multi-user.target
```
To set this permanently, 
```
sudo systemctl set-default multi-user.target
```

How to Kill X service permanently in ubuntu server

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