The following steps will disable NetworkManager service and allows the interface to be managed only by network service.
1. To check which are the interfaces managed by NetworkManager
# nmcli device status
This displays a table that lists all network interfaces along with their STATE. If Network Manager is not controlling an interface, its STATE will be listed as unmanaged. Any other value indicates the interface is under Network Manager control.
2. Stop the NetworkManager service:
# systemctl stop NetworkManager
3. Disable the service permanently:
# systemctl disable NetworkManager
4. To confirm the NetworkManager service has been disabled
# systemctl list-unit-files | grep NetworkManager
5. Add the below parameter in /etc/sysconfig/network-scripts/ifcfg-ethX of interfaces that are managed by NetworkManager to make it unmanaged.
Switching to “network” service
When the NetworkManager is disabled, the interface can be configured for use with the network service. Follow the steps below to configure and interface using network services.
1. Set the IP address in the configuration file: /etc/sysconfig/network-scripts/ifcfg-eth0. Set the NM_CONTROLLED value to no and assign a static IP address in the file.
NAME="eth0" HWADDR=... ONBOOT=yes BOOTPROTO=none IPADDR=... NETMASK=... GATEWAY=... TYPE=Ethernet NM_CONTROLLED=no
2. Set the DNS servers to be used by adding into the file: /etc/resolv.conf :
nameserver [server 1] nameserver [server 2]
3. Enable the network service
# systemctl enable network
4. Restart the network service
# systemctl restart network