How to disable services from booting on debian

To know wich services is running when debian is booting you can check it into /etc/init.d

root@debian:~# cd /etc/init.d/ && ls -all
total 148
drwxr-xr-x   2 root root  4096 avril 23 19:34 .
drwxr-xr-x 126 root root 12288 avril 23 21:05 ..
-rwxr-xr-x   1 root root  5336 mars  30  2019 alsa-utils
-rwxr-xr-x   1 root root  2055 mai   19  2019 anacron
-rwxr-xr-x   1 root root  3740 mars  30  2019 apparmor
-rwxr-xr-x   1 root root  2948 mars  22  2020 bluetooth
-rwxr-xr-x   1 root root  1232 août  15  2019 console-setup.sh
-rwxr-xr-x   1 root root  3059 oct.  11  2019 cron
-rwxr-xr-x   1 root root  1961 avril 10  2019 cups-browsed
-rwxr-xr-x   1 root root  2813 juil.  5  2020 dbus
-rwxr-xr-x   1 root root  3033 févr.  9  2019 gdm3
-rwxr-xr-x   1 root root  3809 janv. 10  2019 hwclock.sh
-rwxr-xr-x   1 root root  1479 oct.  10  2016 keyboard-setup.sh
-rwxr-xr-x   1 root root  2044 févr.  9  2019 kmod
-rwxr-xr-x   1 root root  4445 août  25  2018 networking
-rwxr-xr-x   1 root root  1942 oct.   4  2019 network-manager
-rwxr-xr-x   1 root root  9138 févr. 20  2019 openvpn
-rwxr-xr-x   1 root root  3720 oct.  12  2018 pcscd
-rwxr-xr-x   1 root root  1366 avril  8  2019 plymouth
-rwxr-xr-x   1 root root   752 avril  8  2019 plymouth-log
-rwxr-xr-x   1 root root   612 févr. 20  2020 pppd-dns
-rwxr-xr-x   1 root root   924 mai   31  2018 procps
-rwxr-xr-x   1 root root  2864 févr. 26  2019 rsyslog
-rwxr-xr-x   1 root root  2224 avril 15  2018 saned
-rwxr-xr-x   1 root root  1960 mai    2  2020 speech-dispatcher
-rwxr-xr-x   1 root root  1030 févr.  2  2020 sudo
-rwxr-xr-x   1 root root  6872 oct.  24 20:44 udev
-rwxr-xr-x   1 root root  2083 août  15  2017 ufw
-rwxr-xr-x   1 root root  1391 juin   8  2019 unattended-upgrades
-rwxr-xr-x   1 root root  2757 nov.  23  2016 x11-common
root@debian:/etc/init.d#

Stop one of them from booting

systemctl disable openvpn.service

This is really simple, now you know how to disable one, you can do it with with others !

List all services

systemctl --type=service

You should see this page

Get the status of a service (openvpn.service is an example)

root@debian:/etc/init.d# systemctl status openvpn.service 
● openvpn.service - OpenVPN service
   Loaded: loaded (/lib/systemd/system/openvpn.service; enabled; vendor preset: enabled)
   Active: active (exited) since Fri 2021-04-23 21:05:06 CEST; 17min ago
  Process: 563 ExecStart=/bin/true (code=exited, status=0/SUCCESS)
 Main PID: 563 (code=exited, status=0/SUCCESS)
avril 23 21:05:05 debian systemd[1]: Starting OpenVPN service...
avril 23 21:05:06 debian systemd[1]: Started OpenVPN service.

This one is active, this how to stop it

Stop a service

root@debian:/etc/init.d# systemctl stop openvpn.service 
root@debian:/etc/init.d#

Signed Alix.