Create a System Administrator User on CentOS Server

Requirements

A CentOS server installed, if you didn't installed it yet have a look to the CentOS 6.x Server Installation tutorial.

Create a System Administrator user

1. Login as root user and create an administrator user:

   centos-srv login: root
   Password:
   ...
   # useradd administrator
   # passwd administrator
   Changing password for user administrator.
   New password:
   Retype new password:
   passwd: all authentication tokens updated successfully.
   #
   

2. Logout and login as administrator user, then try to switch to root using su command:

   centos-srv login: administrator
   password:
   $ su -
   Password:
   #
   

3. Make administrator user as the only a user who can switch to root by adding it to the wheel group and editing PAM service configuration:

   # usermod -G wheel administrator         # Add administrator to wheel group
   # vi /etc/pam.d/su
   ...
   # Uncomment the following line to require a user to be in the "wheel" group.
   auth            required        pam_wheel.so use_uid
   ...
   

4. Add administrator to the sudoers file:

   # visudo
   ...
   # Add the following last lines
   # System Administrator can use all root privilege
   administrator    ALL=(ALL)       ALL
   

5. Forward emails for root to administrator user by editing the /etc/aliases file, then run newaliases command:

   # vi /etc/aliases
   ...
   # Person who should get root's mail
   root:           administrator
   ...
   # newaliases
   #
   

Danilo