Configure Sudo to separate users’ duty if some people share privileges.

[1] Install Sudo.

root@localhost:~# apt -y install sudo

[2] Grant root privilege to a user all.

root@localhost:~# visudo
# add to the end: user [soncq] can use all root privilege
soncq    ALL=(ALL:ALL) ALL

# how to write ⇒ [user] [host=(owner)] [command]
# push [Ctrl + x] key to quit visudo
# verify with user [soncq]
soncq@localhost:~$ /sbin/reboot
Failed to set wall message, ignoring: Interactive authentication required.
Failed to reboot system via logind: Interactive authentication required.
Failed to open initctl fifo: Permission denied
Failed to talk to init daemon.
# denied normally
soncq@localhost:~$ sudo /sbin/reboot
[sudo] password for soncq:                # password of [soncq]

Session terminated, terminating shell...   # run normally

[3] In addition to the setting of [1], add settings that some commands are not allowed.

root@localhost:~# visudo
# add alias for the kind of shutdown commands
# Cmnd alias specification

Cmnd_Alias SHUTDOWN = /sbin/halt, /sbin/shutdown, \
/sbin/poweroff, /sbin/reboot, /sbin/init, /bin/systemctl 

# add (commands in alias [SHUTDOWN] are not allowed)
soncq    ALL=(ALL:ALL) ALL, !SHUTDOWN

# verify with user [ubuntu]
soncq@localhost:~$ sudo /sbin/shutdown -r now
[sudo] password for soncq:

Sorry, user soncq is not allowed to execute '/sbin/shutdown -r now' as root on ubuntu.
# denied normally

[4] Grant privilege of some commands to users in a group.

root@localhost:~# visudo
# add aliase for the kind of user management comamnds
# Cmnd alias specification
Cmnd_Alias USERMGR = /usr/sbin/adduser, /usr/sbin/useradd, /usr/sbin/newusers, \
/usr/sbin/deluser, /usr/sbin/userdel, /usr/sbin/usermod, /usr/bin/passwd 

# add to the end
%usermgr ALL=(ALL) USERMGR
root@localhost:~# groupadd usermgr
root@localhost:~# vi /etc/group
# add a user in this group
usermgr:x:1002:soncq
# verify with user [soncq]
soncq@localhost:~$ sudo /usr/sbin/useradd testuser
soncq@localhost:~$     # run normally
soncq@localhost:~$ sudo /usr/bin/passwd testuser
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

[5] Grant privilege of some commands to a user.

root@localhost:~# visudo
# add to the end for each user setting
fedora    ALL=(ALL:ALL) /usr/sbin/visudo
centos    ALL=(ALL:ALL) /usr/sbin/adduser, /usr/sbin/useradd, /usr/sbin/newusers, \
                        /usr/sbin/deluser, /usr/sbin/userdel, /usr/sbin/usermod, /usr/bin/passwd
debian    ALL=(ALL:ALL) /usr/bin/vim

# verify with user [fedora]
fedora@localhost:~$ sudo /usr/sbin/visudo
# run normally
## Sudoers allows particular users to run various commands as
## the root user, without needing the root password.
# verify with user [centos]
centos@localhost:~$ sudo /usr/sbin/userdel -r testuser
centos@localhost:~$     # run normally
# verify with user [debian]
debian@localhost:~$ sudo /usr/bin/vim /root/.profile
# run normally
# ~/.profile: executed by Bourne-compatible login shells.

[6] It’s possible to display Sudo logs on Journald ( with [journalctl] command ) or Rsyslogd ( in [/var/log/auth.log] file ), however, if you’d like to keep only Sudo logs in another file, Configure like follows.

root@localhost:~# visudo
# add to the end
Defaults syslog=local1
root@localhost:~# vi /etc/rsyslog.d/50-default.conf
# line 8 : add
local1.*                        /var/log/sudo.log
auth,authpriv.*;local1.none     /var/log/auth.log
*.*;auth,authpriv.none          -/var/log/syslog

root@localhost:~# systemctl restart rsyslog