How to disable NetworkManager on systemd systems

Introduction

In order to install cPanel on RHEL 8-based systems, the NetworkManager service must be disabled. If the cPanel installation begins and NetworkManager is running, you will encounter the following error:

(ERROR): ********************* ERROR *********************
(ERROR): NetworkManager is installed and running, or
(ERROR): configured to startup.
(ERROR):
(ERROR): cPanel does not support NetworkManager enabled
(ERROR): systems. The installation cannot proceed.
(ERROR):
(ERROR): See https://go.cpanel.net/disablenm for more
(ERROR): information on disabling Network Manager.
(ERROR): ********************* ERROR *********************

Please Note: The cPanel installer will automatically disable the Network Manager when installing on AlmaLinux and Rocky Linux 8 systems.

Procedure

1. Access the server's command line as the "root" user via SSH or "Terminal" in WHM.
2. Stop the NetworkManager service.

   systemctl stop NetworkManager

3. Disable the NetworkManager service.

   systemctl disable NetworkManager

4. Open each of the files at the following path in your preferred text editor:

   /etc/sysconfig/network-scripts/ifcfg-*

5. Change the NM_CONTROLLED  value to "no".

   NM_CONTROLLED=no

   Please note that if the NM_CONTROLLED entry doesn't exist, do not add it.
6. Change the ONBOOT value to "yes".

   ONBOOT=yes

   Please note that if the ONBOOT entry doesn't exist, do not add it.
7. Save the changes and exit the text editor.
8. Enable the network service.

   systemctl enable network.service

9. Start the network service.

   systemctl start network.service

Additional resources

How to Disable Network Manager