RHEL 8 New Features for Experienced Linux Administrators
Objectives
After completing this section, students should be able to explain how the NetworkManager service has become an integral and mandatory component in modern network management, and to configure complex, layered network interfaces and components.
Introducing NetworkManager
NetworkManager is the preferred network configuration tool in Red Hat Enterprise Linux 8. It can handle complex configurations, and layered products such as OpenStack, OpenShift, and Red Hat Virtualization now rely on it.
Configuring the Network with NetworkManager
Red Hat recommends using NetworkManager for network configuration.
NetworkManager can now handle complex configurations, such as Open vSwitch or SR-IOV.
Layered products, such as OpenStack, are using NetworkManager.
Multiple front ends are available: the web console, nmcli, nmtui, and the Network RHEL System Role.
The Systemd
networkservice and the network scripts are no longer available.ifup and ifdown are links to NetworkManager scripts.
Configuring System Networks with NetworkManager
NetworkManager provides a uniform way to configure the system network across different Red Hat Enterprise Linux releases. Because the Network Red Hat Enterprise Linux System Role relies on NetworkManager, you can often use a single Playbook for multiple RHEL releases.
In RHEL 8, the system does not install the legacy Systemd network service.
However, NetworkManager still relies on the configuration files in the /etc/sysconfig/network-scripts/ directory.
You can still edit those files, and use the ifup command for NetworkManager to reread the interface configuration.
[user@demo ~]#vim /etc/sysconfig/network-scripts/ifcfg-ens3[user@demo ~]#ifup ens3
The ifup and ifdown commands are now links to scripts that call the nmcli command to reload the configuration from the ifcfg-* file and start or stop the connection.
References
NetworkManager(8), nmcli(1), and nmtui(1) man pages
For more information, refer to the Configuring and managing networking guide at https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html-single/configuring_and_managing_networking/
