You need to execute the network manager commands through DBUS, which means you can’t just do nmcli inside the container and expect it to work. You can see here: https://github.com/NetworkManager/NetworkManager/blob/master/examples/shell/disconnect-device.sh for example how the dbus-send command is used to send a command through DBUS to the NetworkManager. I think the code there is a great example on how to achieve what you want to do.