NetworkManager and netplan
The default netplan configuration files in Ubuntu Core leave management of networking devices to networkd. But, when network-manager is installed, it creates new netplan configuration files, setting itself as the default network renderer and taking control of all devices.
It is possible to control this behavior with the
defaultrenderer snap option. It is set by default to
true , but if we set it to
false , network-manager reverts the netplan configuration and networkd takes control of the devices again. Note however that networkd will take control only of devices explicitly configured by netplan configuration files, which is usually only ethernet or wifi devices. To do that:
snap set network-manager defaultrenderer=false
In the core16 snap (legacy), the behavior was different: networkd was left as default renderer and the default netplan configuration was unchanged when network-manager was installed. There was instead a setting called
ethernet.enable that was
false by default. When set to
true , NetworkManager was set as the default network renderer similarly as described above.